RE: (ITS#4308) poor performance under load

[KevinS@bmrb.co.uk]

In addition to the trace I just sent I'm also seeing the following when
I don't have ldapsearch running (but CPU for that thread is still high)
#0  0xff01db44 in _poll () from /usr/lib/libc.so.1
#1  0xfefd2a08 in select_large_fdset () from /usr/lib/libc.so.1
#2  0x0003bdac in slapd_daemon_destroy ()
#3  0xfef157bc in _lwp_start () from /usr/lib/libthread.so.1

-----Original Message-----
From: Howard Chu [mailto:hyc@symas.com] 
Sent: 05 January 2006 23:23
To: Spicer, Kevin (MBLEA it)
Cc: openldap-its@OpenLDAP.org
Subject: Re: (ITS#4308) poor performance under load

Attach to the slapd process with gdb and get a stack trace. We need to 
see what that CPU hogging thread is doing.

kevins@bmrb.co.uk wrote:
>
> Following some advice I took a look at the output of prstat -L, it
seems that
> one thread is using lots of CPU (2.3.14 16 threads)
> prstat -L -p `cat /var/run/slapd/slapd.pid`
>    PID USERNAME  SIZE   RSS STATE  PRI NICE      TIME  CPU
PROCESS/LWPID
>  11383 ldap      245M   28M cpu0     0    0   0:00:17  28% slapd/2
>  11383 ldap      245M   28M sleep   59    0   0:00:00 1.0% slapd/17
>  11383 ldap      245M   28M sleep   59    0   0:00:00 0.7% slapd/15
>  11383 ldap      245M   28M sleep   59    0   0:00:00 0.6% slapd/16
>  11383 ldap      245M   28M sleep   59    0   0:00:00 0.6% slapd/10
>  11383 ldap      245M   28M sleep   59    0   0:00:00 0.6% slapd/14
>  11383 ldap      245M   28M sleep   59    0   0:00:00 0.6% slapd/13
>  11383 ldap      245M   28M sleep   59    0   0:00:00 0.6% slapd/4
>  11383 ldap      245M   28M sleep   59    0   0:00:00 0.6% slapd/7
>  11383 ldap      245M   28M sleep   59    0   0:00:00 0.6% slapd/11
>  11383 ldap      245M   28M sleep   59    0   0:00:00 0.5% slapd/3
>  11383 ldap      245M   28M sleep   59    0   0:00:00 0.5% slapd/5
>  11383 ldap      245M   28M sleep   59    0   0:00:00 0.5% slapd/6
>  11383 ldap      245M   28M sleep   59    0   0:00:00 0.4% slapd/9
>  11383 ldap      245M   28M sleep   59    0   0:00:00 0.4% slapd/8
>  11383 ldap      245M   28M sleep   59    0   0:00:00 0.4% slapd/12
>  11383 ldap      245M   28M sleep   59    0   0:00:00 0.1% slapd/1
>  11383 ldap      245M   28M sleep   59    0   0:00:00 0.0% slapd/18
>
> After the test completes that one thread continues to eat cpu for up
to several
> minutes. 
>
>
>   


-- 
  -- Howard Chu
  Chief Architect, Symas Corp.  http://www.symas.com
  Director, Highland Sun        http://highlandsun.com/hyc
  OpenLDAP Core Team            http://www.openldap.org/project/


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