On 1:59 PM, Christopher Schultz wrote:
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Andy,
On 5/8/12 6:41 PM, Andy Wang wrote:
Initial benchmarks seem to show that the behavior between tomcats
is not an issue.
Do you mean that Tomcat performance appears to be the same regardless
of version? That's both good and bad... I thought there were some
performance improvements to the connectors from 5.5-> 6.0. Maybe that
was 4.x->5.5.
Tomcat7 is using JDK 1.7 and this is interesting. The benchmarks
with tomcat7+jdk1.7 vary widely across the board (both through ajp
and direct http to tomcat) from 30s-40sMB/s. Java 1.6 seems alot
more consistent. Not sure why yet.
That is interesting. On the other hand, the server /is/ on a virtual
machine, and you never know what other processes are stealing focus.
Many VMs are notorious for bad IO throughput (I'm looking at you, OpenVZ).
I've also moved off the crappy Windows XP VM I was provided to a
more recent Windows 2008 VM as well as a fresh Windows XP SP3 VM.
In past experience it seems windows XP and windows 2003 were the
worst of the bunch with the ajp downloads dropping as low as
4-5MB/s over time.
Have you tried bare hardware?
How much control do you have over the VM server? Seems to me that
resources/performance could be not only affected by other VMs but also
intentionally throttled.
-Terence Bandoian
I'm going to run a barrage of tests and provide the numbers. Do
you think ab -n 5 and allowing ab to average the values of 5 hits
for the ~440MB iso is a sound average?
Some tips for this kind of testing:
1. Don't run ab on localhost: all the numbers will be worthless
2. Run ab with a range of concurrencies, including c=1
3. Make /lots/ of requests. IMO, 5 requests is really a pinhole
analysis. I would make as many requests as you can over 10 minutes and
see what the throughput ends up being.
I'll compare Windows XP performance and Windows 2008 performance
and after that I'll do the same on a Linux VM to get a better
comparison.
It will be good to see.
If you want some really crappy scripts to get you going, feel free to
start with mine from a while back (look in the "scripts" subdir):
http://people.apache.org/~schultz/ApacheCon%20NA%202010/
Those scripts can run a ... lot of ab tests with lots of different
concurrencies against a series of URLs -- that allows you to set up
everything with, say, a different path or port number to get the
various setups (bare httpd, httpd+mod_jk, httpd+mod_proxy, etc.) and
then let it run all night. It will also produce some tables for you
that can then easily be graphed.
I also did bump up the ajpPacket size to 64K with no noticeable
change to the benchmark numbers. So while 8k seems crappy it
doesn't seem to be an issue. Given that apache and tomcat are both
local I wouldn't expect that to be a big problem with 8k chunks
given the near non-existent latency of local connections.
It's good to know that the packet size didn't affect performance, but
I agree that localhost communication is always magically-fast no mater
what.
I plan on doing both local ab requests as well as remote. The
problem with remote is that our network is busy, so it may account
for some variations but I don't think I can get our IT to segment
me anything for this purpose :(.
Just get a crossover cable and use static IP addresses.
I'm not so concerned about a 25% hit. I'm really more concerned
with the drop to 4-5MB/s over time that seems to happen.
Does this happen locally or only remotely? I wonder if you're hitting
some kind of traffic-shaping or QOS rules on your own internal network.
- -chris
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org
For additional commands, e-mail: users-h...@tomcat.apache.org
