Re: why is AsyncLoggerContextSelector faster?
Hello Remko, I think I found the difference. AsyncLoggerContextSelector always returns the same instance of AsyncLoggerContext, which in turns always returns instances of AsyncLogger, which uses disruptor to handle concurrency. However, with any other selector, a standard Logger instance is returned and parallelism is achieved through an AsyncAppender. AsyncAppender use a standard blocking queue instead of using disruptor which explains the performance difference (there's also the fact that AsyncLoggerContextSelector always returns the same context instance and does not spend cycles in the lookup, but I think that is not a significant cost once everything was warmed out). http://logging.apache.org/log4j/2.x/manual/async.html says that when using mixed type loggers disruptor is needed on the classpath. That seems to be an error. For what I see disruptor is only used when setting all loggers asynchronous. Does this make sense? Anyway around this? Do you have a disruptor appender somewhere? Thanks! On Sat, Jul 19, 2014 at 11:55 PM, Remko Popma remko.po...@gmail.com wrote: To be honest, I haven't investigated in detail the reason for the difference in throughput in the performance test. Are you measuring the performance of your application container, and can you see an improvement when using Async Loggers? Do you see a large difference in performance _in your application_ between making all loggers Asynchronous and using mixed synchronous and Asynchronous loggers? On Sun, Jul 20, 2014 at 7:45 AM, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Hello Remko, Thanks for the insight. I guess my case falls into the wrong end of the pareto law. My project is a low latency application container, so I need to have: - low latency - log separation (I actually had to implement my own context selector because my logic is more complicated than the standard ClassLoaderContextSelector case) - I want async loggers by default, but deployed apps need to be able to specify sync loggers Right now I'm kinda meeting those requirements using config file, AsyncRoot and my custom selector, but it'd be really great to achieve a performance level like the one that AsyncContextSelector promises. Is there a way of doing that? For what I see on the code, the AsyncLoggerContextSelector's secret sauce is just to always return an AsyncLogger on the newInstance() method. Why is that so much faster than what ClassLoaderLoggerContextSelector does? Thanks! On Fri, Jul 18, 2014 at 1:20 PM, Remko Popma remko.po...@gmail.com wrote: The Async Loggers created with the context selector have a slightly different mechanism. One of the differences is that LogEvent objects are re-used. However, unless your application is in the low-latency space, I would not worry too much about the performance difference. Both flavors of Async Loggers are much faster than the alternative (Async Appenders). Your point is valid though. I've been thinking about an alternative way to configure Async Loggers than via system properties. The work in progress is tracked in Jira ticket LOG4J2-321 https://issues.apache.org/jira/browse/LOG4J2-321. This is still in the concept phase though. Meanwhile your best option is probably to use ClassLoaderContextSelector and configure with AsyncRoot and AsyncLogger. On Fri, Jul 18, 2014 at 10:57 PM, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Hello, According to the performance charts in the documentation, log4j2 has a significantly higher throughput when using AsyncLoggerContextSelector than when using all async loggers with any different selector. Why is that? Is it just because the same context is always reused and there's no lookup like in the ClassLoaderContextSelector case? If I need functionality similar to ClassLoaderContextSelector, is there any way to get a throughput similar to AsyncLoggerContextSelector? Thanks!
Re: why is AsyncLoggerContextSelector faster?
Hi, No that is incorrect. If you do not specify AsyncLoggerContextSelector but instead configure with AsyncRoot and AsyncLogger loggers, you _do_ need the disruptor jar on the classpath and this does _not_ use AsyncAppender. AsyncAppender is completely separate from Async Loggers. Async Loggers (mixed or all async) use the disruptor and both need the disruptor jar. You keep mentioning a performance difference. I was assuming you were talking about the performance test results mentioned on the Async Logger manual page, but perhaps I was wrong? Are you experiencing a performance difference between the two flavors of Async Loggers in your application? On Mon, Jul 21, 2014 at 11:10 PM, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Hello Remko, I think I found the difference. AsyncLoggerContextSelector always returns the same instance of AsyncLoggerContext, which in turns always returns instances of AsyncLogger, which uses disruptor to handle concurrency. However, with any other selector, a standard Logger instance is returned and parallelism is achieved through an AsyncAppender. AsyncAppender use a standard blocking queue instead of using disruptor which explains the performance difference (there's also the fact that AsyncLoggerContextSelector always returns the same context instance and does not spend cycles in the lookup, but I think that is not a significant cost once everything was warmed out). http://logging.apache.org/log4j/2.x/manual/async.html says that when using mixed type loggers disruptor is needed on the classpath. That seems to be an error. For what I see disruptor is only used when setting all loggers asynchronous. Does this make sense? Anyway around this? Do you have a disruptor appender somewhere? Thanks! On Sat, Jul 19, 2014 at 11:55 PM, Remko Popma remko.po...@gmail.com wrote: To be honest, I haven't investigated in detail the reason for the difference in throughput in the performance test. Are you measuring the performance of your application container, and can you see an improvement when using Async Loggers? Do you see a large difference in performance _in your application_ between making all loggers Asynchronous and using mixed synchronous and Asynchronous loggers? On Sun, Jul 20, 2014 at 7:45 AM, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Hello Remko, Thanks for the insight. I guess my case falls into the wrong end of the pareto law. My project is a low latency application container, so I need to have: - low latency - log separation (I actually had to implement my own context selector because my logic is more complicated than the standard ClassLoaderContextSelector case) - I want async loggers by default, but deployed apps need to be able to specify sync loggers Right now I'm kinda meeting those requirements using config file, AsyncRoot and my custom selector, but it'd be really great to achieve a performance level like the one that AsyncContextSelector promises. Is there a way of doing that? For what I see on the code, the AsyncLoggerContextSelector's secret sauce is just to always return an AsyncLogger on the newInstance() method. Why is that so much faster than what ClassLoaderLoggerContextSelector does? Thanks! On Fri, Jul 18, 2014 at 1:20 PM, Remko Popma remko.po...@gmail.com wrote: The Async Loggers created with the context selector have a slightly different mechanism. One of the differences is that LogEvent objects are re-used. However, unless your application is in the low-latency space, I would not worry too much about the performance difference. Both flavors of Async Loggers are much faster than the alternative (Async Appenders). Your point is valid though. I've been thinking about an alternative way to configure Async Loggers than via system properties. The work in progress is tracked in Jira ticket LOG4J2-321 https://issues.apache.org/jira/browse/LOG4J2-321. This is still in the concept phase though. Meanwhile your best option is probably to use ClassLoaderContextSelector and configure with AsyncRoot and AsyncLogger. On Fri, Jul 18, 2014 at 10:57 PM, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Hello, According to the performance charts in the documentation, log4j2 has a significantly higher throughput when using AsyncLoggerContextSelector than when using all async loggers with any different selector. Why is that? Is it just because the same context is always reused and there's no lookup like in the ClassLoaderContextSelector case? If I need functionality similar to ClassLoaderContextSelector, is there any way to get a throughput similar to AsyncLoggerContextSelector? Thanks!
Re: why is AsyncLoggerContextSelector faster?
I think he's talking about the ClassLoaderContextSelector which attempts to find the logger context through several different ways. Using the sun.reflect.Reflection class to get the caller class itself is one of those techniques which might slow things down a little. I actually have a change to LogManager that can help speed up LoggerContext resolution when you create a Logger using a Class? instead of a String. The ClassLoader of that Class should be passed to the LoggerContextFactory to help speed up resolution of the appropriate LoggerContext. On 21 July 2014 09:22, Remko Popma remko.po...@gmail.com wrote: Hi, No that is incorrect. If you do not specify AsyncLoggerContextSelector but instead configure with AsyncRoot and AsyncLogger loggers, you _do_ need the disruptor jar on the classpath and this does _not_ use AsyncAppender. AsyncAppender is completely separate from Async Loggers. Async Loggers (mixed or all async) use the disruptor and both need the disruptor jar. You keep mentioning a performance difference. I was assuming you were talking about the performance test results mentioned on the Async Logger manual page, but perhaps I was wrong? Are you experiencing a performance difference between the two flavors of Async Loggers in your application? On Mon, Jul 21, 2014 at 11:10 PM, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Hello Remko, I think I found the difference. AsyncLoggerContextSelector always returns the same instance of AsyncLoggerContext, which in turns always returns instances of AsyncLogger, which uses disruptor to handle concurrency. However, with any other selector, a standard Logger instance is returned and parallelism is achieved through an AsyncAppender. AsyncAppender use a standard blocking queue instead of using disruptor which explains the performance difference (there's also the fact that AsyncLoggerContextSelector always returns the same context instance and does not spend cycles in the lookup, but I think that is not a significant cost once everything was warmed out). http://logging.apache.org/log4j/2.x/manual/async.html says that when using mixed type loggers disruptor is needed on the classpath. That seems to be an error. For what I see disruptor is only used when setting all loggers asynchronous. Does this make sense? Anyway around this? Do you have a disruptor appender somewhere? Thanks! On Sat, Jul 19, 2014 at 11:55 PM, Remko Popma remko.po...@gmail.com wrote: To be honest, I haven't investigated in detail the reason for the difference in throughput in the performance test. Are you measuring the performance of your application container, and can you see an improvement when using Async Loggers? Do you see a large difference in performance _in your application_ between making all loggers Asynchronous and using mixed synchronous and Asynchronous loggers? On Sun, Jul 20, 2014 at 7:45 AM, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Hello Remko, Thanks for the insight. I guess my case falls into the wrong end of the pareto law. My project is a low latency application container, so I need to have: - low latency - log separation (I actually had to implement my own context selector because my logic is more complicated than the standard ClassLoaderContextSelector case) - I want async loggers by default, but deployed apps need to be able to specify sync loggers Right now I'm kinda meeting those requirements using config file, AsyncRoot and my custom selector, but it'd be really great to achieve a performance level like the one that AsyncContextSelector promises. Is there a way of doing that? For what I see on the code, the AsyncLoggerContextSelector's secret sauce is just to always return an AsyncLogger on the newInstance() method. Why is that so much faster than what ClassLoaderLoggerContextSelector does? Thanks! On Fri, Jul 18, 2014 at 1:20 PM, Remko Popma remko.po...@gmail.com wrote: The Async Loggers created with the context selector have a slightly different mechanism. One of the differences is that LogEvent objects are re-used. However, unless your application is in the low-latency space, I would not worry too much about the performance difference. Both flavors of Async Loggers are much faster than the alternative (Async Appenders). Your point is valid though. I've been thinking about an alternative way to configure Async Loggers than via system properties. The work in progress is tracked in Jira ticket LOG4J2-321 https://issues.apache.org/jira/browse/LOG4J2-321. This is still in the concept phase though. Meanwhile your best option is probably to use ClassLoaderContextSelector and
Re: why is AsyncLoggerContextSelector faster?
Hello Remko, I'm still a couple of days away from starting my own performance testing. I'm taking about the difference in the async loggers manual page, more specifically, the charts that compare sync loggers, to mixed async loggers against purely async loggers. Since I need to build my own selector, I'm trying to be clear on how this works internally in order to implement the less latency possible selector and try to minimize the performance testing effort. Thanks for the clarifications! On Mon, Jul 21, 2014 at 11:22 AM, Remko Popma remko.po...@gmail.com wrote: Hi, No that is incorrect. If you do not specify AsyncLoggerContextSelector but instead configure with AsyncRoot and AsyncLogger loggers, you _do_ need the disruptor jar on the classpath and this does _not_ use AsyncAppender. AsyncAppender is completely separate from Async Loggers. Async Loggers (mixed or all async) use the disruptor and both need the disruptor jar. You keep mentioning a performance difference. I was assuming you were talking about the performance test results mentioned on the Async Logger manual page, but perhaps I was wrong? Are you experiencing a performance difference between the two flavors of Async Loggers in your application? On Mon, Jul 21, 2014 at 11:10 PM, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Hello Remko, I think I found the difference. AsyncLoggerContextSelector always returns the same instance of AsyncLoggerContext, which in turns always returns instances of AsyncLogger, which uses disruptor to handle concurrency. However, with any other selector, a standard Logger instance is returned and parallelism is achieved through an AsyncAppender. AsyncAppender use a standard blocking queue instead of using disruptor which explains the performance difference (there's also the fact that AsyncLoggerContextSelector always returns the same context instance and does not spend cycles in the lookup, but I think that is not a significant cost once everything was warmed out). http://logging.apache.org/log4j/2.x/manual/async.html says that when using mixed type loggers disruptor is needed on the classpath. That seems to be an error. For what I see disruptor is only used when setting all loggers asynchronous. Does this make sense? Anyway around this? Do you have a disruptor appender somewhere? Thanks! On Sat, Jul 19, 2014 at 11:55 PM, Remko Popma remko.po...@gmail.com wrote: To be honest, I haven't investigated in detail the reason for the difference in throughput in the performance test. Are you measuring the performance of your application container, and can you see an improvement when using Async Loggers? Do you see a large difference in performance _in your application_ between making all loggers Asynchronous and using mixed synchronous and Asynchronous loggers? On Sun, Jul 20, 2014 at 7:45 AM, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Hello Remko, Thanks for the insight. I guess my case falls into the wrong end of the pareto law. My project is a low latency application container, so I need to have: - low latency - log separation (I actually had to implement my own context selector because my logic is more complicated than the standard ClassLoaderContextSelector case) - I want async loggers by default, but deployed apps need to be able to specify sync loggers Right now I'm kinda meeting those requirements using config file, AsyncRoot and my custom selector, but it'd be really great to achieve a performance level like the one that AsyncContextSelector promises. Is there a way of doing that? For what I see on the code, the AsyncLoggerContextSelector's secret sauce is just to always return an AsyncLogger on the newInstance() method. Why is that so much faster than what ClassLoaderLoggerContextSelector does? Thanks! On Fri, Jul 18, 2014 at 1:20 PM, Remko Popma remko.po...@gmail.com wrote: The Async Loggers created with the context selector have a slightly different mechanism. One of the differences is that LogEvent objects are re-used. However, unless your application is in the low-latency space, I would not worry too much about the performance difference. Both flavors of Async Loggers are much faster than the alternative (Async Appenders). Your point is valid though. I've been thinking about an alternative way to configure Async Loggers than via system properties. The work in progress is tracked in Jira ticket LOG4J2-321 https://issues.apache.org/jira/browse/LOG4J2-321. This is still in the concept phase though. Meanwhile your best option is probably to use ClassLoaderContextSelector and configure with AsyncRoot and AsyncLogger.
Re: why is AsyncLoggerContextSelector faster?
Well, the way to go that's similar to the async version is to use the BasicContextSelector which contains a singleton LoggerContext. Otherwise, you'll have to keep your own registry that can be looked up dynamically such as through reflection of the caller stack and other fun design problems. :) On 21 July 2014 09:35, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Hello Remko, I'm still a couple of days away from starting my own performance testing. I'm taking about the difference in the async loggers manual page, more specifically, the charts that compare sync loggers, to mixed async loggers against purely async loggers. Since I need to build my own selector, I'm trying to be clear on how this works internally in order to implement the less latency possible selector and try to minimize the performance testing effort. Thanks for the clarifications! On Mon, Jul 21, 2014 at 11:22 AM, Remko Popma remko.po...@gmail.com wrote: Hi, No that is incorrect. If you do not specify AsyncLoggerContextSelector but instead configure with AsyncRoot and AsyncLogger loggers, you _do_ need the disruptor jar on the classpath and this does _not_ use AsyncAppender. AsyncAppender is completely separate from Async Loggers. Async Loggers (mixed or all async) use the disruptor and both need the disruptor jar. You keep mentioning a performance difference. I was assuming you were talking about the performance test results mentioned on the Async Logger manual page, but perhaps I was wrong? Are you experiencing a performance difference between the two flavors of Async Loggers in your application? On Mon, Jul 21, 2014 at 11:10 PM, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Hello Remko, I think I found the difference. AsyncLoggerContextSelector always returns the same instance of AsyncLoggerContext, which in turns always returns instances of AsyncLogger, which uses disruptor to handle concurrency. However, with any other selector, a standard Logger instance is returned and parallelism is achieved through an AsyncAppender. AsyncAppender use a standard blocking queue instead of using disruptor which explains the performance difference (there's also the fact that AsyncLoggerContextSelector always returns the same context instance and does not spend cycles in the lookup, but I think that is not a significant cost once everything was warmed out). http://logging.apache.org/log4j/2.x/manual/async.html says that when using mixed type loggers disruptor is needed on the classpath. That seems to be an error. For what I see disruptor is only used when setting all loggers asynchronous. Does this make sense? Anyway around this? Do you have a disruptor appender somewhere? Thanks! On Sat, Jul 19, 2014 at 11:55 PM, Remko Popma remko.po...@gmail.com wrote: To be honest, I haven't investigated in detail the reason for the difference in throughput in the performance test. Are you measuring the performance of your application container, and can you see an improvement when using Async Loggers? Do you see a large difference in performance _in your application_ between making all loggers Asynchronous and using mixed synchronous and Asynchronous loggers? On Sun, Jul 20, 2014 at 7:45 AM, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Hello Remko, Thanks for the insight. I guess my case falls into the wrong end of the pareto law. My project is a low latency application container, so I need to have: - low latency - log separation (I actually had to implement my own context selector because my logic is more complicated than the standard ClassLoaderContextSelector case) - I want async loggers by default, but deployed apps need to be able to specify sync loggers Right now I'm kinda meeting those requirements using config file, AsyncRoot and my custom selector, but it'd be really great to achieve a performance level like the one that AsyncContextSelector promises. Is there a way of doing that? For what I see on the code, the AsyncLoggerContextSelector's secret sauce is just to always return an AsyncLogger on the newInstance() method. Why is that so much faster than what ClassLoaderLoggerContextSelector does? Thanks! On Fri, Jul 18, 2014 at 1:20 PM, Remko Popma remko.po...@gmail.com wrote: The Async Loggers created with the context selector have a slightly different mechanism. One of the differences is that LogEvent objects are re-used. However, unless your application is in the low-latency space, I would not worry too much about the performance difference. Both flavors of Async Loggers
Re: why is AsyncLoggerContextSelector faster?
Matt, not sure what you mean. Mariano needs to develop his own ContextSelector to achieve log separation. So he cannot use the AsyncLoggerContextSelector. Mariano, I would not be overly concerned with the performance results mentioned on the async logger manual page. Bear in mind that in that performance test, _all_ that the program does is logging. In the real world (your application) that will obviously not be true: your application will do many other things. Also, mixed async loggers performed much, much better than AsyncAppenders. So, unless you have actual measurement numbers for _your_ application, not the theoretical numbers from the async logger manual page, I would keep it simple at first, just get your custom selector to work well, and then start measuring performance. If you are getting strange results, like AsyncAppenders performing better than AsyncLoggers, then let us know and we'll try to help figure out what the problem is. On Mon, Jul 21, 2014 at 11:38 PM, Matt Sicker boa...@gmail.com wrote: Well, the way to go that's similar to the async version is to use the BasicContextSelector which contains a singleton LoggerContext. Otherwise, you'll have to keep your own registry that can be looked up dynamically such as through reflection of the caller stack and other fun design problems. :) On 21 July 2014 09:35, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Hello Remko, I'm still a couple of days away from starting my own performance testing. I'm taking about the difference in the async loggers manual page, more specifically, the charts that compare sync loggers, to mixed async loggers against purely async loggers. Since I need to build my own selector, I'm trying to be clear on how this works internally in order to implement the less latency possible selector and try to minimize the performance testing effort. Thanks for the clarifications! On Mon, Jul 21, 2014 at 11:22 AM, Remko Popma remko.po...@gmail.com wrote: Hi, No that is incorrect. If you do not specify AsyncLoggerContextSelector but instead configure with AsyncRoot and AsyncLogger loggers, you _do_ need the disruptor jar on the classpath and this does _not_ use AsyncAppender. AsyncAppender is completely separate from Async Loggers. Async Loggers (mixed or all async) use the disruptor and both need the disruptor jar. You keep mentioning a performance difference. I was assuming you were talking about the performance test results mentioned on the Async Logger manual page, but perhaps I was wrong? Are you experiencing a performance difference between the two flavors of Async Loggers in your application? On Mon, Jul 21, 2014 at 11:10 PM, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Hello Remko, I think I found the difference. AsyncLoggerContextSelector always returns the same instance of AsyncLoggerContext, which in turns always returns instances of AsyncLogger, which uses disruptor to handle concurrency. However, with any other selector, a standard Logger instance is returned and parallelism is achieved through an AsyncAppender. AsyncAppender use a standard blocking queue instead of using disruptor which explains the performance difference (there's also the fact that AsyncLoggerContextSelector always returns the same context instance and does not spend cycles in the lookup, but I think that is not a significant cost once everything was warmed out). http://logging.apache.org/log4j/2.x/manual/async.html says that when using mixed type loggers disruptor is needed on the classpath. That seems to be an error. For what I see disruptor is only used when setting all loggers asynchronous. Does this make sense? Anyway around this? Do you have a disruptor appender somewhere? Thanks! On Sat, Jul 19, 2014 at 11:55 PM, Remko Popma remko.po...@gmail.com wrote: To be honest, I haven't investigated in detail the reason for the difference in throughput in the performance test. Are you measuring the performance of your application container, and can you see an improvement when using Async Loggers? Do you see a large difference in performance _in your application_ between making all loggers Asynchronous and using mixed synchronous and Asynchronous loggers? On Sun, Jul 20, 2014 at 7:45 AM, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Hello Remko, Thanks for the insight. I guess my case falls into the wrong end of the pareto law. My project is a low latency application container, so I need to have: - low latency - log separation (I actually had to implement my own context selector because my logic is more complicated than the
Re: why is AsyncLoggerContextSelector faster?
Mariano, to clarify, I would recommend that you keep your custom context selector simple and only use it for the log separation that you mentioned. I would not recommend that you also somehow try to merge the functionality of AsyncLoggerContextSelector in your context selector. From a performance perspective that should not be necessary. If you use AsyncRoot and AsyncLogger in your configuration then I doubt that logging will be a performance bottleneck. On Mon, Jul 21, 2014 at 11:47 PM, Remko Popma remko.po...@gmail.com wrote: Matt, not sure what you mean. Mariano needs to develop his own ContextSelector to achieve log separation. So he cannot use the AsyncLoggerContextSelector. Mariano, I would not be overly concerned with the performance results mentioned on the async logger manual page. Bear in mind that in that performance test, _all_ that the program does is logging. In the real world (your application) that will obviously not be true: your application will do many other things. Also, mixed async loggers performed much, much better than AsyncAppenders. So, unless you have actual measurement numbers for _your_ application, not the theoretical numbers from the async logger manual page, I would keep it simple at first, just get your custom selector to work well, and then start measuring performance. If you are getting strange results, like AsyncAppenders performing better than AsyncLoggers, then let us know and we'll try to help figure out what the problem is. On Mon, Jul 21, 2014 at 11:38 PM, Matt Sicker boa...@gmail.com wrote: Well, the way to go that's similar to the async version is to use the BasicContextSelector which contains a singleton LoggerContext. Otherwise, you'll have to keep your own registry that can be looked up dynamically such as through reflection of the caller stack and other fun design problems. :) On 21 July 2014 09:35, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Hello Remko, I'm still a couple of days away from starting my own performance testing. I'm taking about the difference in the async loggers manual page, more specifically, the charts that compare sync loggers, to mixed async loggers against purely async loggers. Since I need to build my own selector, I'm trying to be clear on how this works internally in order to implement the less latency possible selector and try to minimize the performance testing effort. Thanks for the clarifications! On Mon, Jul 21, 2014 at 11:22 AM, Remko Popma remko.po...@gmail.com wrote: Hi, No that is incorrect. If you do not specify AsyncLoggerContextSelector but instead configure with AsyncRoot and AsyncLogger loggers, you _do_ need the disruptor jar on the classpath and this does _not_ use AsyncAppender. AsyncAppender is completely separate from Async Loggers. Async Loggers (mixed or all async) use the disruptor and both need the disruptor jar. You keep mentioning a performance difference. I was assuming you were talking about the performance test results mentioned on the Async Logger manual page, but perhaps I was wrong? Are you experiencing a performance difference between the two flavors of Async Loggers in your application? On Mon, Jul 21, 2014 at 11:10 PM, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Hello Remko, I think I found the difference. AsyncLoggerContextSelector always returns the same instance of AsyncLoggerContext, which in turns always returns instances of AsyncLogger, which uses disruptor to handle concurrency. However, with any other selector, a standard Logger instance is returned and parallelism is achieved through an AsyncAppender. AsyncAppender use a standard blocking queue instead of using disruptor which explains the performance difference (there's also the fact that AsyncLoggerContextSelector always returns the same context instance and does not spend cycles in the lookup, but I think that is not a significant cost once everything was warmed out). http://logging.apache.org/log4j/2.x/manual/async.html says that when using mixed type loggers disruptor is needed on the classpath. That seems to be an error. For what I see disruptor is only used when setting all loggers asynchronous. Does this make sense? Anyway around this? Do you have a disruptor appender somewhere? Thanks! On Sat, Jul 19, 2014 at 11:55 PM, Remko Popma remko.po...@gmail.com wrote: To be honest, I haven't investigated in detail the reason for the difference in throughput in the performance test. Are you measuring the performance of your application container, and can you see an improvement when using Async Loggers? Do you see a large difference in performance _in your application_ between making all loggers Asynchronous
Re: why is AsyncLoggerContextSelector faster?
Thanks Remko and Matt for your comments. I will take your suggestions and let you know how it goes. Just out of curiosity (I don't like to use libraries blindly and way too curious), where are the loggers instantiated/configured?? I followed the code of XmlConfiguration but it seems to only parse configuration items, I couldn't find where it parses and configures the loggers. I admit I didn't look that hard, but if you could provide a pointer to better understand how this all works that'd be great. Thanks! On Mon, Jul 21, 2014 at 12:12 PM, Remko Popma remko.po...@gmail.com wrote: Mariano, to clarify, I would recommend that you keep your custom context selector simple and only use it for the log separation that you mentioned. I would not recommend that you also somehow try to merge the functionality of AsyncLoggerContextSelector in your context selector. From a performance perspective that should not be necessary. If you use AsyncRoot and AsyncLogger in your configuration then I doubt that logging will be a performance bottleneck. On Mon, Jul 21, 2014 at 11:47 PM, Remko Popma remko.po...@gmail.com wrote: Matt, not sure what you mean. Mariano needs to develop his own ContextSelector to achieve log separation. So he cannot use the AsyncLoggerContextSelector. Mariano, I would not be overly concerned with the performance results mentioned on the async logger manual page. Bear in mind that in that performance test, _all_ that the program does is logging. In the real world (your application) that will obviously not be true: your application will do many other things. Also, mixed async loggers performed much, much better than AsyncAppenders. So, unless you have actual measurement numbers for _your_ application, not the theoretical numbers from the async logger manual page, I would keep it simple at first, just get your custom selector to work well, and then start measuring performance. If you are getting strange results, like AsyncAppenders performing better than AsyncLoggers, then let us know and we'll try to help figure out what the problem is. On Mon, Jul 21, 2014 at 11:38 PM, Matt Sicker boa...@gmail.com wrote: Well, the way to go that's similar to the async version is to use the BasicContextSelector which contains a singleton LoggerContext. Otherwise, you'll have to keep your own registry that can be looked up dynamically such as through reflection of the caller stack and other fun design problems. :) On 21 July 2014 09:35, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Hello Remko, I'm still a couple of days away from starting my own performance testing. I'm taking about the difference in the async loggers manual page, more specifically, the charts that compare sync loggers, to mixed async loggers against purely async loggers. Since I need to build my own selector, I'm trying to be clear on how this works internally in order to implement the less latency possible selector and try to minimize the performance testing effort. Thanks for the clarifications! On Mon, Jul 21, 2014 at 11:22 AM, Remko Popma remko.po...@gmail.com wrote: Hi, No that is incorrect. If you do not specify AsyncLoggerContextSelector but instead configure with AsyncRoot and AsyncLogger loggers, you _do_ need the disruptor jar on the classpath and this does _not_ use AsyncAppender. AsyncAppender is completely separate from Async Loggers. Async Loggers (mixed or all async) use the disruptor and both need the disruptor jar. You keep mentioning a performance difference. I was assuming you were talking about the performance test results mentioned on the Async Logger manual page, but perhaps I was wrong? Are you experiencing a performance difference between the two flavors of Async Loggers in your application? On Mon, Jul 21, 2014 at 11:10 PM, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Hello Remko, I think I found the difference. AsyncLoggerContextSelector always returns the same instance of AsyncLoggerContext, which in turns always returns instances of AsyncLogger, which uses disruptor to handle concurrency. However, with any other selector, a standard Logger instance is returned and parallelism is achieved through an AsyncAppender. AsyncAppender use a standard blocking queue instead of using disruptor which explains the performance difference (there's also the fact that AsyncLoggerContextSelector always returns the same context instance and does not spend cycles in the lookup, but I think that is not a significant cost once everything was warmed out). http://logging.apache.org/log4j/2.x/manual/async.html says that when using mixed type loggers disruptor is needed on the
Re: why is AsyncLoggerContextSelector faster?
Take a look at http://logging.apache.org/log4j/2.x/manual/architecture.html. The configuration creates the LoggerConfig objects, not the Loggers. Loggers are created by applications and associated with LoggerConfigs. XMLConfiguration and JSONConfiguration are responsible for parsing their respective configuration files and then turning them into a tree of Node objects. AbstractConfiguration then converts the tree into the actual objects using the Plugin mechanism. Ralph On Jul 21, 2014, at 8:41 AM, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Thanks Remko and Matt for your comments. I will take your suggestions and let you know how it goes. Just out of curiosity (I don't like to use libraries blindly and way too curious), where are the loggers instantiated/configured?? I followed the code of XmlConfiguration but it seems to only parse configuration items, I couldn't find where it parses and configures the loggers. I admit I didn't look that hard, but if you could provide a pointer to better understand how this all works that'd be great. Thanks! On Mon, Jul 21, 2014 at 12:12 PM, Remko Popma remko.po...@gmail.com wrote: Mariano, to clarify, I would recommend that you keep your custom context selector simple and only use it for the log separation that you mentioned. I would not recommend that you also somehow try to merge the functionality of AsyncLoggerContextSelector in your context selector. From a performance perspective that should not be necessary. If you use AsyncRoot and AsyncLogger in your configuration then I doubt that logging will be a performance bottleneck. On Mon, Jul 21, 2014 at 11:47 PM, Remko Popma remko.po...@gmail.com wrote: Matt, not sure what you mean. Mariano needs to develop his own ContextSelector to achieve log separation. So he cannot use the AsyncLoggerContextSelector. Mariano, I would not be overly concerned with the performance results mentioned on the async logger manual page. Bear in mind that in that performance test, _all_ that the program does is logging. In the real world (your application) that will obviously not be true: your application will do many other things. Also, mixed async loggers performed much, much better than AsyncAppenders. So, unless you have actual measurement numbers for _your_ application, not the theoretical numbers from the async logger manual page, I would keep it simple at first, just get your custom selector to work well, and then start measuring performance. If you are getting strange results, like AsyncAppenders performing better than AsyncLoggers, then let us know and we'll try to help figure out what the problem is. On Mon, Jul 21, 2014 at 11:38 PM, Matt Sicker boa...@gmail.com wrote: Well, the way to go that's similar to the async version is to use the BasicContextSelector which contains a singleton LoggerContext. Otherwise, you'll have to keep your own registry that can be looked up dynamically such as through reflection of the caller stack and other fun design problems. :) On 21 July 2014 09:35, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Hello Remko, I'm still a couple of days away from starting my own performance testing. I'm taking about the difference in the async loggers manual page, more specifically, the charts that compare sync loggers, to mixed async loggers against purely async loggers. Since I need to build my own selector, I'm trying to be clear on how this works internally in order to implement the less latency possible selector and try to minimize the performance testing effort. Thanks for the clarifications! On Mon, Jul 21, 2014 at 11:22 AM, Remko Popma remko.po...@gmail.com wrote: Hi, No that is incorrect. If you do not specify AsyncLoggerContextSelector but instead configure with AsyncRoot and AsyncLogger loggers, you _do_ need the disruptor jar on the classpath and this does _not_ use AsyncAppender. AsyncAppender is completely separate from Async Loggers. Async Loggers (mixed or all async) use the disruptor and both need the disruptor jar. You keep mentioning a performance difference. I was assuming you were talking about the performance test results mentioned on the Async Logger manual page, but perhaps I was wrong? Are you experiencing a performance difference between the two flavors of Async Loggers in your application? On Mon, Jul 21, 2014 at 11:10 PM, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Hello Remko, I think I found the difference. AsyncLoggerContextSelector always returns the same instance of AsyncLoggerContext, which in turns always returns instances of AsyncLogger, which uses disruptor to handle concurrency. However, with any other selector, a standard Logger instance is returned and parallelism is achieved through an AsyncAppender. AsyncAppender use a standard blocking queue instead of using disruptor
Re: why is AsyncLoggerContextSelector faster?
Hello Remko, Thanks for the insight. I guess my case falls into the wrong end of the pareto law. My project is a low latency application container, so I need to have: - low latency - log separation (I actually had to implement my own context selector because my logic is more complicated than the standard ClassLoaderContextSelector case) - I want async loggers by default, but deployed apps need to be able to specify sync loggers Right now I'm kinda meeting those requirements using config file, AsyncRoot and my custom selector, but it'd be really great to achieve a performance level like the one that AsyncContextSelector promises. Is there a way of doing that? For what I see on the code, the AsyncLoggerContextSelector's secret sauce is just to always return an AsyncLogger on the newInstance() method. Why is that so much faster than what ClassLoaderLoggerContextSelector does? Thanks! On Fri, Jul 18, 2014 at 1:20 PM, Remko Popma remko.po...@gmail.com wrote: The Async Loggers created with the context selector have a slightly different mechanism. One of the differences is that LogEvent objects are re-used. However, unless your application is in the low-latency space, I would not worry too much about the performance difference. Both flavors of Async Loggers are much faster than the alternative (Async Appenders). Your point is valid though. I've been thinking about an alternative way to configure Async Loggers than via system properties. The work in progress is tracked in Jira ticket LOG4J2-321 https://issues.apache.org/jira/browse/LOG4J2-321. This is still in the concept phase though. Meanwhile your best option is probably to use ClassLoaderContextSelector and configure with AsyncRoot and AsyncLogger. On Fri, Jul 18, 2014 at 10:57 PM, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Hello, According to the performance charts in the documentation, log4j2 has a significantly higher throughput when using AsyncLoggerContextSelector than when using all async loggers with any different selector. Why is that? Is it just because the same context is always reused and there's no lookup like in the ClassLoaderContextSelector case? If I need functionality similar to ClassLoaderContextSelector, is there any way to get a throughput similar to AsyncLoggerContextSelector? Thanks!
Re: why is AsyncLoggerContextSelector faster?
To be honest, I haven't investigated in detail the reason for the difference in throughput in the performance test. Are you measuring the performance of your application container, and can you see an improvement when using Async Loggers? Do you see a large difference in performance _in your application_ between making all loggers Asynchronous and using mixed synchronous and Asynchronous loggers? On Sun, Jul 20, 2014 at 7:45 AM, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Hello Remko, Thanks for the insight. I guess my case falls into the wrong end of the pareto law. My project is a low latency application container, so I need to have: - low latency - log separation (I actually had to implement my own context selector because my logic is more complicated than the standard ClassLoaderContextSelector case) - I want async loggers by default, but deployed apps need to be able to specify sync loggers Right now I'm kinda meeting those requirements using config file, AsyncRoot and my custom selector, but it'd be really great to achieve a performance level like the one that AsyncContextSelector promises. Is there a way of doing that? For what I see on the code, the AsyncLoggerContextSelector's secret sauce is just to always return an AsyncLogger on the newInstance() method. Why is that so much faster than what ClassLoaderLoggerContextSelector does? Thanks! On Fri, Jul 18, 2014 at 1:20 PM, Remko Popma remko.po...@gmail.com wrote: The Async Loggers created with the context selector have a slightly different mechanism. One of the differences is that LogEvent objects are re-used. However, unless your application is in the low-latency space, I would not worry too much about the performance difference. Both flavors of Async Loggers are much faster than the alternative (Async Appenders). Your point is valid though. I've been thinking about an alternative way to configure Async Loggers than via system properties. The work in progress is tracked in Jira ticket LOG4J2-321 https://issues.apache.org/jira/browse/LOG4J2-321. This is still in the concept phase though. Meanwhile your best option is probably to use ClassLoaderContextSelector and configure with AsyncRoot and AsyncLogger. On Fri, Jul 18, 2014 at 10:57 PM, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Hello, According to the performance charts in the documentation, log4j2 has a significantly higher throughput when using AsyncLoggerContextSelector than when using all async loggers with any different selector. Why is that? Is it just because the same context is always reused and there's no lookup like in the ClassLoaderContextSelector case? If I need functionality similar to ClassLoaderContextSelector, is there any way to get a throughput similar to AsyncLoggerContextSelector? Thanks!
Re: why is AsyncLoggerContextSelector faster?
The Async Loggers created with the context selector have a slightly different mechanism. One of the differences is that LogEvent objects are re-used. However, unless your application is in the low-latency space, I would not worry too much about the performance difference. Both flavors of Async Loggers are much faster than the alternative (Async Appenders). Your point is valid though. I've been thinking about an alternative way to configure Async Loggers than via system properties. The work in progress is tracked in Jira ticket LOG4J2-321 https://issues.apache.org/jira/browse/LOG4J2-321. This is still in the concept phase though. Meanwhile your best option is probably to use ClassLoaderContextSelector and configure with AsyncRoot and AsyncLogger. On Fri, Jul 18, 2014 at 10:57 PM, Mariano Gonzalez mariano.l.gonza...@gmail.com wrote: Hello, According to the performance charts in the documentation, log4j2 has a significantly higher throughput when using AsyncLoggerContextSelector than when using all async loggers with any different selector. Why is that? Is it just because the same context is always reused and there's no lookup like in the ClassLoaderContextSelector case? If I need functionality similar to ClassLoaderContextSelector, is there any way to get a throughput similar to AsyncLoggerContextSelector? Thanks!
