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RE: (ITS#4308) poor performance under load

To: openldap-its@OpenLDAP.org
Subject: RE: (ITS#4308) poor performance under load
From: KevinS@bmrb.co.uk
Date: Fri, 6 Jan 2006 01:00:04 GMT
-----Original Message-----
From: Howard Chu [mailto:hyc@symas.com] 

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

I have to confess I don't know very much about using gdb, and have never
done it with threads before - so I hope you'll excuse me and point me in
the right direction if this isn't what you want...

######
First... output of prstat -L 
######

   PID USERNAME  SIZE   RSS STATE  PRI NICE      TIME  CPU PROCESS/LWPID
 22870 ldap      258M   33M stop    30    0   0:00:26  17% slapd/2
 22870 ldap      258M   33M stop    49    0   0:00:01 0.9% slapd/7
 22870 ldap      258M   33M stop    49    0   0:00:01 0.7% slapd/5
 22870 ldap      258M   33M stop    49    0   0:00:01 0.7% slapd/4
 22870 ldap      258M   33M stop    49    0   0:00:00 0.7% slapd/8
 22870 ldap      258M   33M stop    49    0   0:00:01 0.6% slapd/6
 22870 ldap      258M   33M stop    49    0   0:00:01 0.6% slapd/3
 22870 ldap      258M   33M stop    49    0   0:00:00 0.5% slapd/13
 22870 ldap      258M   33M stop    49    0   0:00:00 0.4% slapd/10
 22870 ldap      258M   33M stop    49    0   0:00:00 0.4% slapd/9
 22870 ldap      258M   33M stop    49    0   0:00:00 0.4% slapd/17
 22870 ldap      258M   33M stop    49    0   0:00:00 0.4% slapd/11
 22870 ldap      258M   33M stop    49    0   0:00:00 0.4% slapd/12
 22870 ldap      258M   33M stop    49    0   0:00:00 0.4% slapd/18
 22870 ldap      258M   33M stop    49    0   0:00:00 0.4% slapd/15
 22870 ldap      258M   33M stop    49    0   0:00:00 0.4% slapd/14
 22870 ldap      258M   33M stop    49    0   0:00:00 0.3% slapd/16
 22870 ldap      258M   33M stop    59    0   0:00:00 0.0% slapd/1

######
now gdb (I've included the full output so you can see if I'm doing
anything wrong!)
######

GNU gdb 6.0
Copyright 2003 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you
are
welcome to change it and/or distribute copies of it under certain
conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for
details.
This GDB was configured as "sparc-sun-solaris2.9".
(gdb) attach 22870
Attaching to process 22870
Reading symbols from /usr/local/libexec/slapd...(no debugging symbols
found)...
done.
Reading symbols from /usr/local/ssl/lib/libssl.so.0.9.7...
(no debugging symbols found)...done.
Loaded symbols for /usr/local/ssl/lib/libssl.so.0.9.7
Reading symbols from /usr/local/ssl/lib/libcrypto.so.0.9.7...
(no debugging symbols found)...done.
Loaded symbols for /usr/local/ssl/lib/libcrypto.so.0.9.7
Reading symbols from /usr/lib/libresolv.so.2...(no debugging symbols
found)...
done.
Loaded symbols for /usr/lib/libresolv.so.2
Reading symbols from /usr/lib/libgen.so.1...(no debugging symbols
found)...
done.
Loaded symbols for /usr/lib/libgen.so.1
Reading symbols from /usr/lib/libnsl.so.1...(no debugging symbols
found)...
done.
Loaded symbols for /usr/lib/libnsl.so.1
Reading symbols from /usr/lib/libsocket.so.1...(no debugging symbols
found)...
done.
Loaded symbols for /usr/lib/libsocket.so.1
Reading symbols from /usr/lib/libdl.so.1...(no debugging symbols
found)...done.
Loaded symbols for /usr/lib/libdl.so.1
Reading symbols from /usr/sfw/lib/libwrap.so.1...
(no debugging symbols found)...done.
Loaded symbols for /usr/sfw/lib/libwrap.so.1
Reading symbols from /usr/lib/libpthread.so.1...(no debugging symbols
found)...
done.
Loaded symbols for /usr/lib/libpthread.so.1
Reading symbols from /usr/lib/libc.so.1...(no debugging symbols
found)...done.
Loaded symbols for /usr/lib/libc.so.1
Reading symbols from /usr/local/lib/libgcc_s.so.1...done.
Loaded symbols for /usr/local/lib/libgcc_s.so.1
Reading symbols from /usr/lib/libmp.so.2...done.
Loaded symbols for /usr/lib/libmp.so.2
---Type <return> to continue, or q <return> to quit---
Reading symbols from
/usr/platform/SUNW,Sun-Fire-V240/lib/libc_psr.so.1...done.
Loaded symbols for /usr/platform/SUNW,Sun-Fire-V240/lib/libc_psr.so.1
Reading symbols from /usr/lib/libthread.so.1...done.
warning: sol_thread_new_objfile: td_ta_new: Debugger service failed
Loaded symbols for /usr/lib/libthread.so.1
Reading symbols from /usr/lib/libldap.so.5...done.
warning: sol_thread_new_objfile: td_ta_new: Debugger service failed
Loaded symbols for /usr/lib/libldap.so.5
Reading symbols from /usr/lib/librt.so.1...done.
warning: sol_thread_new_objfile: td_ta_new: Debugger service failed
Loaded symbols for /usr/lib/librt.so.1
Reading symbols from /usr/lib/libmd5.so.1...done.
warning: sol_thread_new_objfile: td_ta_new: Debugger service failed
Loaded symbols for /usr/lib/libmd5.so.1
Reading symbols from /usr/lib/libaio.so.1...done.
warning: sol_thread_new_objfile: td_ta_new: Debugger service failed
Loaded symbols for /usr/lib/libaio.so.1
Reading symbols from
/usr/local/libexec/openldap/ppolicy-2.3.so.0...done.
warning: sol_thread_new_objfile: td_ta_new: Debugger service failed
Loaded symbols for /usr/local/libexec/openldap/ppolicy-2.3.so.0
Reading symbols from /usr/local/lib/libltdl.so.3...done.
warning: sol_thread_new_objfile: td_ta_new: Debugger service failed
Loaded symbols for /usr/local/lib/libltdl.so.3
Retry #1:
Retry #2:
Retry #3:
Retry #4:
[New LWP 1]
Symbols already loaded for /usr/local/ssl/lib/libssl.so.0.9.7
Symbols already loaded for /usr/local/ssl/lib/libcrypto.so.0.9.7
Symbols already loaded for /usr/lib/libresolv.so.2
Symbols already loaded for /usr/lib/libgen.so.1
Symbols already loaded for /usr/lib/libnsl.so.1
Symbols already loaded for /usr/lib/libsocket.so.1
Symbols already loaded for /usr/lib/libdl.so.1
Symbols already loaded for /usr/sfw/lib/libwrap.so.1
Symbols already loaded for /usr/lib/libpthread.so.1
Symbols already loaded for /usr/lib/libc.so.1
Symbols already loaded for /usr/local/lib/libgcc_s.so.1
Symbols already loaded for /usr/lib/libmp.so.2
Symbols already loaded for
/usr/platform/SUNW,Sun-Fire-V240/lib/libc_psr.so.1
Symbols already loaded for /usr/lib/libthread.so.1
Symbols already loaded for /usr/lib/libldap.so.5
Symbols already loaded for /usr/lib/librt.so.1
Symbols already loaded for /usr/lib/libmd5.so.1
Symbols already loaded for /usr/lib/libaio.so.1
Symbols already loaded for /usr/local/libexec/openldap/ppolicy-2.3.so.0
Symbols already loaded for /usr/local/lib/libltdl.so.3
0xff01f870 in _lwp_wait () from /usr/lib/libc.so.1
(gdb) info threads
  18 LWP 2  0xff01fb74 in time () from /usr/lib/libc.so.1
  17 LWP 3  0xfef158f4 in __lwp_park () from /usr/lib/libthread.so.1
  16 LWP 4  0xfef158f4 in __lwp_park () from /usr/lib/libthread.so.1
  15 LWP 5  0xfef158f4 in __lwp_park () from /usr/lib/libthread.so.1
  14 LWP 6  0xfef158f4 in __lwp_park () from /usr/lib/libthread.so.1
  13 LWP 7  0xfef158f4 in __lwp_park () from /usr/lib/libthread.so.1
  12 LWP 8  0xfef158f4 in __lwp_park () from /usr/lib/libthread.so.1
  11 LWP 9  0xfef158f4 in __lwp_park () from /usr/lib/libthread.so.1
  10 LWP 10  0xfef158f4 in __lwp_park () from /usr/lib/libthread.so.1
  9 LWP 11  0xfef158f4 in __lwp_park () from /usr/lib/libthread.so.1
  8 LWP 12  0xfef158f4 in __lwp_park () from /usr/lib/libthread.so.1
  7 LWP 13  0xfef158f4 in __lwp_park () from /usr/lib/libthread.so.1
  6 LWP 14  0xfef158f4 in __lwp_park () from /usr/lib/libthread.so.1
  5 LWP 15  0xfef158f4 in __lwp_park () from /usr/lib/libthread.so.1
  4 LWP 16  0xfef158f4 in __lwp_park () from /usr/lib/libthread.so.1
  3 LWP 17  0xfef158f4 in __lwp_park () from /usr/lib/libthread.so.1
  2 LWP 18  0xfef158f4 in __lwp_park () from /usr/lib/libthread.so.1
* 1 LWP 1  0xff01f870 in _lwp_wait () from /usr/lib/libc.so.1
(gdb) thread 18
[Switching to thread 18 (LWP 2)]#0  0xff01fb74 in time ()
   from /usr/lib/libc.so.1
(gdb) bt
#0  0xff01fb74 in time () from /usr/lib/libc.so.1
#1  0x000e6d14 in ldap_pvt_runqueue_resched ()
#2  0x0003b660 in slapd_daemon_destroy ()
#3  0xfef157bc in _lwp_start () from /usr/lib/libthread.so.1
(gdb) detach
Detaching from program:  LWP 2
(gdb) quit

=================================================================

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