I have a machine serving a simple CGI that serve text file to client. The server is pitty busy serving several millions hits per day.

The CGI is served by apache and I have squid setup as accelator in front. Yeterday after upgradding squid from 2.4 STABLE7 to 2.5 STABLE4, I noticed a major performance drop in the server. I have kept the squid config file and complied 2.5 STABLE 4 using the same config directive as I did with 2.4. I have also tried 2.5 STABLE 2 which basically give me the same result

Checking the server-status report from apache, I notice apache behave very differently from 2.4 to 2.5

This is what I get when 2.5 STBALE2/4 is used

Server Version: Apache/1.3.27 (Unix) mod_perl/1.27
Server Built: Nov 6 2002 13:13:57
Current Time: Wednesday, 24-Sep-2003 02:55:55 GMT
Restart Time: Wednesday, 24-Sep-2003 02:52:42 GMT
Parent Server Generation: 0
Server uptime: 3 minutes 13 seconds
Total accesses: 21817 - Total Traffic: 2.7 MB
CPU Usage: u86.52 s40.05 cu0 cs0 - 65.6% CPU load
113 requests/sec - 14.4 kB/second - 130 B/request
100 requests currently being processed, 0 idle servers

RRRRRRRRRRRRRRRRRRRRWRRRRRRRRRRRRWWRRRRRRRRRRRRRRRRRRRRWRRRRWRRR
RRRRRRRRRRRRRRRRRRRRRRRRRWRRRRRRRWRR............................
................................................................
................................................................


and this is what I get when 2.4 STABLE 7 is used


Server Version: Apache/1.3.27 (Unix) mod_perl/1.27
Server Built: Nov 6 2002 13:13:57
Current Time: Wednesday, 24-Sep-2003 03:04:13 GMT
Restart Time: Wednesday, 24-Sep-2003 03:00:18 GMT
Parent Server Generation: 0
Server uptime: 3 minutes 55 seconds
Total accesses: 41708 - Total Traffic: 4.6 MB
CPU Usage: u165.54 s71.51 cu0 cs0 - 101% CPU load
177 requests/sec - 20.1 kB/second - 115 B/request
100 requests currently being processed, 0 idle servers

WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW
WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW............................
................................................................
................................................................

Scoreboard Key:
"_" Waiting for Connection, "S" Starting up, "R" Reading Request,
"W" Sending Reply, "K" Keepalive (read), "D" DNS Lookup,
"L" Logging, "G" Gracefully finishing, "." Open slot with no current process



Somehow it appears that with 2.5, apache are all stuck in 'Reading Request' state while with 2.4 request move smoothly.

Any idea what I can do to fix this?



Here's more info of the server
- Redhat 7.2 box running 2.4.18 kernel

- This is what I used to complie squid (both 2.5.and 2.4)
--enable-async-io --enable-dl-malloc

- Here's some (I think) important setting of squid config I'm using

request_timeout 30 seconds
connect_timeout 30 seconds

httpd_accel_single_host on
httpd_accel_with_proxy on

(using default setting of cache_dir)

client_persistent_connections off
server_persistent_connections off



Many thanks.

Tor.

--
<!---------------------------------------------
                          Victor
                          Development Engineer
                          Outblaze Ltd
---------------------------------------------->




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