Thanks for taking a look. I agree, the site seems to be lasting longer at the moment ... that's a good thing. Startup time is worse than usual (10+ seconds rather than 3 seconds), which isn't good.
I know you guys don't have many resources to actively improve GAE, and I appreciate that you're doing what you can. I look forward to whatever solution you can come up with to improve the situation for everyone: more hardware available, pre-compile Python, pay for warm instance, somehow detect and disable pinging to free up resources for all, whatever. On Dec 14, 9:33 am, Toby Reyelts <to...@google.com> wrote: > I took a few measurements of your app around 9AM PST today (Monday). Your > VMs were timing out at between 90 seconds and two minutes. As you've > noticed, the number of loading requests increases as the amount of traffic > on App Engine increases. This is why we discourage active pinging. > > On Fri, Dec 11, 2009 at 9:16 PM, Devel63 <danstic...@gmail.com> wrote: > > Toby, > > > Here's a site that gets almost no traffic (not yet publicized): > >www.lifehints.com > > > Try it Monday morning at 9am PST and see how quickly it times out. > > I've been seeing it apparently time out in a few seconds during the > > workday. I suppose it's possible that what I'm seeing is Google > > firing up another instance, but that sounds unlikely given that > > there's no one else on the site most of the time. > > > On a Friday evening (now), it's staying warm for quite some time. > > > On Dec 11, 8:57 am, Toby Reyelts <to...@google.com> wrote: > > > On Thu, Dec 10, 2009 at 8:19 AM, bFlood <bflood...@gmail.com> wrote: > > > > hi toby > > > > > you said: "VM timeouts are measured on the order of minutes, not > > > > seconds" - I have not seen this in practice since over a year ago when > > > > GAE will still young. currently, every site I've measured is collected > > > > in seconds (10, maybe 20) > > > > Do you have the appids of specific sites that you believe are timing out > > > every 10 seconds? This is not what we're seeing. Are you sure you aren't > > > seeing loading requests to several different VMs in parallel? > > > > also: "to write a "Hello World" python app that responds from a cold > > > > > start on the order of 100m" - again, I have not seen this in practice > > > > for quite some time. the simplest of python sites, with no imports and > > > > very little code seem to start in the 500ms to 1s range (and > > > > sometimes, much longer). Please note Nick's post here, where he > > > > changed his original cold-start metrics:http://bit.ly/6Fsoxv > > > > Nick's example is not "Hello World". He's cold-starting his blogging app > > in > > > less than 500ms. (I personally believe that is quite acceptably > > responsive). > > > > What I'm driving at is that there's a minimum startup time which you can > > not > > > control as a developer, and that startup time is very low for python (on > > > the order of 100ms). Everything else is under your control: What > > > dependencies you have, what web framework you use, whether you push > > static > > > content and use ajax requests, etc... > > > > > I'm now under the impression that slow VM startups is a GAE issue and > > > > while user imports are critical to keep them reasonable once they are > > > > started, there is a lot of overhead that is completely out of our > > > > control. The only way I've found to keep low traffic sites bearable is > > > > to use polling from the task queue, so IMO, the title of this post is > > > > quite appropriate > > > > > cheers > > > > brian > > > > > On Dec 9, 12:26 pm, Toby Reyelts <to...@google.com> wrote: > > > > > Responses inline. > > > > > > On Sun, Dec 6, 2009 at 7:49 PM, Devel63 <danstic...@gmail.com> > > wrote: > > > > > > Toby, you write that it doesn't usually pay to optimize loading > > > > > > requests. > > > > > > > I agree with this whole-heartedly when you have your own server, > > and > > > > > > only load once per day or month. It's probably true using GAE when > > > > > > you have 100K+ page views per day. > > > > > > I think there's a misunderstanding here. What I said was that it's > > not > > > > worth > > > > > optimizing loading requests in regards to quota. Latency is a > > separate > > > > > concern. > > > > > > > But for lower-volume web sites, GAE performance is atrocious. In > > my > > > > > > personal case, we have optimized in all sorts of ways (js > > > > > > minification, liberal use of memcache, image sprites, sticking with > > > > > > Django 0.96, etc.) ... but the typical user experience is quite > > poor. > > > > > > It takes 3-10 seconds for the first page to load, and then often > > the > > > > > > instance is swapped out while the user reads the current page, so > > that > > > > > > the next request experiences the same thing. If the app is warm, > > > > > > performance is fine. > > > > > > If your VM is timing out while a user is actively visiting the site, > > then > > > > > your site is extremely low traffic. VM timeouts are measured on the > > order > > > > of > > > > > minutes, not seconds. So, for example, that means that you didn't > > receive > > > > > any traffic to your VM at all for several minutes between the time > > the > > > > user > > > > > fetched the first and second pages. > > > > > > > Maybe this gets appreciably better as traffic improves, but of > > course, > > > > > > I can't see that at present. > > > > > > Yes, as stated above, VMs are not aggressively collected. In the > > normal > > > > > case, if you have an active user of your website, you shouldn't see a > > > > > cold-start per request. Maybe in your particular case you can > > > > asynchronously > > > > > ping your backend (for example, with an AJAX request) a few seconds > > > > before > > > > > they continue onto the next page? > > > > > > I love GAE in theory, but it's getting > > > > > > > harder to ignore the reality of low-volume performance. > > > > > > As stated above, I think you're falling into a particularly bad > > extreme > > > > > (continuous cold requests for an "active" user). This might require > > some > > > > > creativity (for example, as above) to work around. > > > > > > In terms of speeding up the loading request itself, the good news > > that > > > > the > > > > > bulk of of that time is directly under your control. As an existence > > > > proof > > > > > of this, you should be able to write a "Hello World" python app that > > > > > responds from a cold start on the order of 100ms. This means you > > might > > > > try > > > > > doing things like paring down the dependencies that you load on cold > > > > > requests. You can also take advantage of the fact that requests for > > > > static > > > > > content bypass your VM and are never "cold". So, for example, you can > > > > serve > > > > > a page that is comprised mostly of static content almost instantly, > > and > > > > let > > > > > it make AJAX requests to asynchronously fill in its dynamic content > > as > > > > your > > > > > VM warms up. > > > > > > If you'd rather just pay to have us maintain a warm VM for you, you > > can > > > > vote > > > > > on that issue. > > > > > > > On Dec 4, 3:38 pm, Toby Reyelts <to...@google.com> wrote: > > > > > > > On Oct 23, 3:02 pm, bugaco <ice...@gmail.com> wrote: > > > > > > > > > I had a bit weird experience with this... > > > > > > > > > So I wrote app (http://analytics.bugaco.com) that runs on App > > > > Engine. > > > > > > > > Than I looked at the request logs to see how it is running. > > > > > > > > Request logs suggested that I'm using a lot of CPU time on > > hitting > > > > the > > > > > > > > home page, but after that CPU time significantly decreases. It > > also > > > > > > > > had annoying red flag suggesting that servlet is using > > excessive > > > > > > > > resources and that I need to optimize it. > > > > > > > > Testing a bit, I noticed that pinging lets app be warm, and I > > had > > > > cron > > > > > > > > doing the pings for a few days; while also noticing that it > > does > > > > not > > > > > > > > do anything useful > > > > > > > > > Conclusion: > > > > > > > > 1. If log files don't suggest that you are better off pinging > > > > people > > > > > > > > would not ping > > > > > > > > I'm not sure what you mean here, but we have plans to change the > > > > admin > > > > > > > console to explicitly call out loading requests, so you can take > > that > > > > > > > into account when profiling your application. Until that becomes > > > > > > > available, it's pretty easy for you to detect and log loading > > > > requests > > > > > > > yourself. > > > > > > > > > 2. It is stupid that google counts warming up your app toward > > CPU > > > > time > > > > > > > > (leading to profiling, that leads to pinging) > > > > > > > > A couple of things: > > > > > > > > 1) CPU time doesn't grow on trees, it comes out of your free or > > paid > > > > > > > quota. Why should we hide this from you? > > > > > > > > 2) The number of loading requests your application receives are > > > > > > > inversely proportional to its traffic. If you get more traffic, > > > > you'll > > > > > > > receive fewer loading requests. This means it usually doesn't pay > > to > > > > > > > optimize loading requests, unless you're just trying to reduce > > user > > > > > > > latency. > > > > > > > > > 3. It is very stupid that applications can not denote 'keep > > this > > > > code > > > > > > > > path warm/cache it/or something' that will allow new users not > > to > > > > give > > > > > > > > up on the up until they get first response. > > > > > > > > Unfortunately, it takes an inordinate amount of physical hardware > > to > > > > > > > keep on the order of millions of applications in memory, which is > > > > > > > somewhat counter to free. If our startup optimizations plus your > > own > > > > > > > optimizations don't satisfy you, then maybe you can voice your > > > > opinion > > > > > > > on paying for a warm VM ( > >http://code.google.com/p/googleappengine/ > > > > > > > issues/detail?id=2456)? > > > > > > > > > So, as a conclusion, I think AppEngine is AWESOME. And I also > > think > > > > it > > > > > > > > SUCKS. > > > > > > > > I love SDK, ability to deploy and test and use all the cool > > things. > > > > > > > > I don't like the idea that it can not serve a (entry)page in > > 3-5 > > > > > > > > seconds as I think that it leaves bad taste in users mouth, and > > > > > > > > consequently bad taste in developers mouth. > > > > > > > > > Finally, I am not sure I'll use AppEngine for developing other > > > > > > > > applications as I'd rather go with paid hosting that provides > > some > > > > > > > > level of > > ... > > read more » -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appeng...@googlegroups.com. To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
