Perrin Harkins wrote:
> On Thu, 2004-04-08 at 11:48, Pascal Felber wrote:
> > The server is a [EMAIL PROTECTED]
> > 512MB, running linux 2.4.18-3, Apache 2.0.48, and mod_perl 1.99_08.
>
> That came out more than a year ago. You should be running
> the latest (1.99_13 at the moment) if you're going to do this
> kind of stress testing.
I have tried with the latest release but did not see noticable changes.
> You haven't given us much to go on here. Can you post the
> relevant sections of your conf file(s) (i.e. not the
> boilerplate stuff) and some of your code?
It is mostly the default apache 2.0.48 configuration. I am using prefork
MPM, with the following parameters:
StartServers 5
MinSpareServers 5
MaxSpareServers 10
MaxClients 150
MaxRequestsPerChild 0
I have installed a PerlResponseHandler on a directory of my Web servers.
To track down the problem, I have used a module that simply redirects
the client to another server, as shown in the following code:
sub handler {
my $r = shift;
$r->content_type('text/html');
$r->headers_out->set(Location => "http://www.eurecom.fr";);
return Apache::REDIRECT;
}
My client test program does not follow the redirection, so any URL would
do.
Stas Bekman wrote:
> Neither you are giving us a proper problem report :( We can't even
tell
> whether you are using the prefork or the worker MPM. If you are using
the
> worker mpm that will explain your observation. Starting a new
interpreter
> under server with many loaded modules at run time is *very* slow, due
to perl
> (not mod_perl). If you are using prefork then you may get new
processes
> spawned, but usually forks are very fast. So my guess is that you are
using
> the worker mpm.
I am using the prefork MPM, and I also tried to change the configuration
values so that no new process is ever started during the tests. I made
sure that memory does not fill and the swap is never used during the
tests.
David Hodgkinson wrote:
> What else is running on the machine? what does vmstat show?
There is nothing exotic running on the machine. In fact, it is a
standard RedHat 7.3 distribution with several network services disabled.
Here is the output of vmstat every 10 seconds during a stress test. Do
you notice anything abnormal that would explain the spikes I observe
every 30 seconds? It looks like the 'bo' value is quite irregular.
procs memory swap io system
cpu
r b w swpd free buff cache si so bi bo in cs us
sy id
0 0 1 0 68964 80692 195016 0 0 0 7 58 60 1
0 17
0 0 0 0 68964 80692 195016 0 0 0 5 116 16 0
0 100
0 0 0 0 68964 80692 195016 0 0 0 2 151 38 0
0 100
0 0 0 0 60952 80692 195020 0 0 0 5 392 167 6
1 93
0 0 0 0 60952 80692 195020 0 0 0 25 458 293 1
1 98
1 0 0 0 60940 80696 195020 0 0 0 4 613 407 1
1 98
0 0 0 0 60948 80696 195020 0 0 0 4 750 518 3
2 95
2 0 0 0 60932 80696 195020 0 0 0 4 863 582 4
3 93
2 0 0 0 60932 80696 195020 0 0 0 4 1042 696 3
2 94
1 0 0 0 60940 80696 195020 0 0 0 4 1221 840 4
4 92
1 0 0 0 60940 80700 195016 0 0 0 14 1329 888 3
3 93
2 0 0 0 60932 80700 195016 0 0 0 4 1508 1000 4
5 91
0 0 0 0 60948 80700 195016 0 0 0 4 1688 1091 6
5 90
2 0 0 0 60932 80700 195016 0 0 0 4 1794 1143 8
6 86
1 0 0 0 60940 80700 195016 0 0 0 4 2014 1268 10
7 82
3 0 0 0 60924 80700 195016 0 0 0 4 2145 1340 13
5 82
1 0 0 0 60940 80700 195016 0 0 0 14 2271 1398 13
10 78
3 0 0 0 60924 80700 195016 0 0 0 4 2455 1512 18
15 67
1 0 0 0 60940 80704 195012 0 0 0 4 2529 1525 19
11 70
5 0 0 0 60900 80704 195012 0 0 0 4 2487 1487 18
10 72
0 0 0 0 60948 80704 195012 0 0 0 4 2468 1503 15
12 73
3 0 0 0 60892 80704 195012 0 0 0 4 2424 1486 15
11 74
1 0 0 0 60940 80704 195012 0 0 0 14 2430 1496 14
10 75
1 0 0 0 60940 80704 195012 0 0 0 4 2363 1442 15
9 76
1 0 0 0 60940 80704 195012 0 0 0 4 2211 1366 15
7 78
2 0 0 0 60932 80704 195012 0 0 0 4 1966 1228 8
7 85
1 0 0 0 60940 80704 195012 0 0 0 4 1887 1195 9
4 88
0 0 0 0 60948 80704 195012 0 0 0 4 1790 1161 7
12 81
0 0 0 0 60936 80708 195012 0 0 0 47 1591 1031 13
10 77
0 0 0 0 60936 80708 195012 0 0 0 4 1435 975 11
14 75
1 0 0 0 60928 80708 195012 0 0 0 4 1289 877 12
16 72
1 0 0 0 60928 80708 195012 0 0 0 4 1144 789 11
14 75
0 0 0 0 60936 80708 195012 0 0 0 4 958 668 11
14 75
0 0 0 0 60936 80708 195012 0 0 0 4 913 620 10
15 75
1 0 0 0 60928 80708 195012 0 0 0 13 677 461 8
11 81
0 0 0 0 60936 80708 195012 0 0 0 4 511 335 3
8 88
0 0 0 0 60936 80708 195012 0 0 0 4 380 237 2
8 90
0 0 0 0 60936 80708 195012 0 0 0 4 240 124 1
3 96
0 0 0 0 60936 80708 195012 0 0 0 4 115 15 0
0 100
0 0 0 0 60936 80708 195012 0 0 0 0 104 7 0
0 100
Now, the interesting thing is that I ran the same test on a machine with
a slower CPU but running kernel 2.6.3 (Mandrake 10), and there are
almost no spikes (they do not exceed 100ms). Maybe this is due to the
scheduler (?)
Thanks again for your help,
Pascal Felber
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