[users@httpd] Apache delays assigning a message to a thread

[Nayman Felix-QA5535 <Fe...@motorola.com>]

We've been running some tests with Apache 2.2.4  and Linux 2.6.21.  When
sending 20 simultaneous HTTP GETs (one process with 20 threads sending
simultaneously), we're seeing that sometimes there is a 3, 4  or even
more second delay for some of the HTTP GETs appearing in the apache_log.
I've captured a wireshark trace and in some cases we see retransmissions
occurring, but in other cases we don't.  Here is a sample of the apache
logs. Note that all of the gets were originally sent out in the same
second at 19:32:09.  We've run these tests a number of times and seen
similar results.  Anyone have any idea why this could be occurring.  Is
this some kind of Denial of Service issue or something else?
 
Thanks,
Felix
 
- 10.16.65.31 - - [04/Apr/2008:19:32:09 +0000] 112000 3627 "GET
/mmsc/MMS?uid=007044A0637500003540001402 HTTP/1.0" 200 590
- 10.16.65.31 - - [04/Apr/2008:19:32:09 +0000] 148000 3694 "GET
/mmsc/MMS?uid=007044A0637500003540001401 HTTP/1.0" 200 590
- 10.16.65.31 - - [04/Apr/2008:19:32:09 +0000] 112000 3828 "GET
/mmsc/MMS?uid=007044A0637500003540001404 HTTP/1.0" 200 590
- 10.16.65.31 - - [04/Apr/2008:19:32:09 +0000] 112000 3761 "GET
/mmsc/MMS?uid=007044A0637500003540001403 HTTP/1.0" 200 590
- 10.16.65.31 - - [04/Apr/2008:19:32:09 +0000] 100000 3962 "GET
/mmsc/MMS?uid=007044A0637500003540001412 HTTP/1.0" 200 590
- 10.16.65.31 - - [04/Apr/2008:19:32:09 +0000] 108000 3962 "GET
/mmsc/MMS?uid=007044A063750000354000140B HTTP/1.0" 200 590
- 10.16.65.31 - - [04/Apr/2008:19:32:09 +0000] 120000 3895 "GET
/mmsc/MMS?uid=007044A063750000354000140D HTTP/1.0" 200 590
- 10.16.65.31 - - [04/Apr/2008:19:32:09 +0000] 116000 4029 "GET
/mmsc/MMS?uid=007044A063750000354000140F HTTP/1.0" 200 590
- 10.16.65.31 - - [04/Apr/2008:19:32:09 +0000] 116000 4029 "GET
/mmsc/MMS?uid=007044A0637500003540001413 HTTP/1.0" 200 590
- 10.16.65.31 - - [04/Apr/2008:19:32:12 +0000] 112000 4230 "GET
/mmsc/MMS?uid=007044A0637500003540001408 HTTP/1.0" 200 590
- 10.16.65.31 - - [04/Apr/2008:19:32:12 +0000] 112000 4364 "GET
/mmsc/MMS?uid=007044A0637500003540001409 HTTP/1.0" 200 590
- 10.16.65.31 - - [04/Apr/2008:19:32:12 +0000] 116000 4297 "GET
/mmsc/MMS?uid=007044A0637500003540001411 HTTP/1.0" 200 590
- 10.16.65.31 - - [04/Apr/2008:19:32:12 +0000] 112000 4364 "GET
/mmsc/MMS?uid=007044A063750000354000140C HTTP/1.0" 200 590
- 10.16.65.31 - - [04/Apr/2008:19:32:18 +0000] 132000 4767 "GET
/mmsc/MMS?uid=007044A0637500003540001407 HTTP/1.0" 200 590
- 10.16.65.31 - - [04/Apr/2008:19:32:18 +0000] 132000 5108 "GET
/mmsc/MMS?uid=007044A063750000354000140A HTTP/1.0" 200 590
- 10.16.65.31 - - [04/Apr/2008:19:32:18 +0000] 152000 5108 "GET
/mmsc/MMS?uid=007044A0637500003540001405 HTTP/1.0" 200 590
- 10.16.65.31 - - [04/Apr/2008:19:32:18 +0000] 184000 4632 "GET
/mmsc/MMS?uid=007044A063750000354000140E HTTP/1.0" 200 590
- 10.16.65.31 - - [04/Apr/2008:19:32:18 +0000] 184000 4699 "GET
/mmsc/MMS?uid=007044A0637500003540001406 HTTP/1.0" 200 590
- 10.16.65.31 - - [04/Apr/2008:19:32:18 +0000] 184000 4498 "GET
/mmsc/MMS?uid=007044A0637500003540001410 HTTP/1.0" 200 590
- 10.16.65.31 - - [04/Apr/2008:19:32:18 +0000] 192000 4565 "GET
/mmsc/MMS?uid=007044A0637500003540001414 HTTP/1.0" 200 590