Poor web serving performance

[Brad Fitzpatrick]

And the IO::AIO test suite passes?  (I assume, since you said the
Linux::AIO one failed...)

Definitely looks like it's not working.  I wonder if the tests aren't
aggressive enough... can you tell if they exercise the set_minimum()
function at all and verify somehow that it works?  (counting
threads/processes, or testing max outstanding AIOs... though the latter
seems hard without being able to fake and slow down the filesystem...)


On Thu, 25 Jan 2007, Cal Henderson wrote:

> Brad Fitzpatrick <brad at danga.com> wrote:
> : Sure doesn't look like it's working!  Unless it's using NPTL?  What
> : arch/kernel you using?
>
> [calh at pc12 Perlbal-1.53]$ cat /etc/redhat-release
> Red Hat Enterprise Linux AS release 4 (Nahant Update 2)
>
> [calh at pc12 Perlbal-1.53]$ uname -a
> Linux pc12.xxxxxxx.com 2.6.9-22.ELsmp #1 SMP Mon Sep 19 18:32:14 EDT
> 2005 i686 i686 i386 GNU/Linux
>
> [calh at pc12 Perlbal-1.53]$ perl -V | grep archname
>     osname=linux, osvers=linux, archname=i686-linux-64int
>
> [calh at pc12 Perlbal-1.53]$ getconf GNU_LIBPTHREAD_VERSION
> NPTL 2.3.4
>
>
> so it /is/ using NPTL threads. if i switch to linuxthreads:
>
> [calh at pc12 Perlbal-1.53]$ export LD_ASSUME_KERNEL=2.4.19
> [calh at pc12 Perlbal-1.53]$ getconf GNU_LIBPTHREAD_VERSION
> linuxthreads-0.10
>
> then i can see the additional processes spawning. however, on startup,
> i only see 2 processes:
>
> [calh at pc12 Perlbal-1.53]$ pstree -aclp | grep perlbal
>   |                   --perl,25351 ./perlbal --config=my.conf
>   |                       --perl,25352 ./perlbal --config=my.conf
>
> and then when i throw some load at it, more processes get created:
>
> [calh at pc12 Perlbal-1.53]$ pstree -aclp | grep perlbal
>   |                   --perl,25351 ./perlbal --config=my.conf
>   |                       --perl,25352 ./perlbal --config=my.conf
>   |                       --perl,25362 ./perlbal --config=my.conf
>   |                           --perl,25363 ./perlbal --config=my.conf
>   |                           --perl,25364 ./perlbal --config=my.conf
>   |                           --perl,25365 ./perlbal --config=my.conf
>   |                           --perl,25366 ./perlbal --config=my.conf
>
> but never the amount i specified using SERVER aio_threads = 40 (and i
> don't get better performance).
>
> any ideas?
>
>
> thanks,
>
> --cal
>
>