Re: Fine-grained locking for POSIX local sockets (UNIX domain sockets)

From: Sven Petai <hadara_at_bsd.ee>
Date: Sun, 7 May 2006 22:00:41 +0300
> Anyhow, what I'm getting at is this: make sure when you measure MySQL
> performance, you do a series of runs, discard the first few, and then take
> an average of the remainder, and watch out for outliers.

The results in my mail were mean values over 2 runs,
only once did I see really huge (more than 10%) differences between several 
subsequent runs with same settings, this case was clearly mentioned in the results.

graph was drawn from resultset available _at_
http://bsd.ee/~hadara/debug/mysql4/freebsd_current_06.02.2006_uds_patch/smack_results_ULE.txt
as you can see each setting was tested twise and mean value was used, 
there doesnt seem to be any significant outliers in that dataset too.

Tomorrow I'll try to get mutex profile while running with your patch,
profiles for non-patched case are already available _at_
http://bsd.ee/~hadara/debug/mysql4/freebsd_current_06.02.2006/mutex_profile_thr_4bsd_select_smack_100-10000.txt

most contended locks:
   max        total       count   avg     cnt_hold     cnt_lock name
  8143    926138412    36000820    25    111228313     34861067 /usr/src/sys/kern/uipc_usrreq.c:309 (unp)
     9         1359         223     6          167     31657721 /usr/src/sys/kern/uipc_usrreq.c:709 (unp)
  6107    123376889     4000519    30     12373564      3900209 /usr/src/sys/kern/uipc_usrreq.c:364 (unp)
 34045    553265364     7972969    69      3951680      3101074 /usr/src/sys/kern/kern_descrip.c:378 (Giant)
1893100    355809996    44119592     8       602861       927204 /usr/src/sys/kern/kern_descrip.c:2011 (filedesc structure)
807479    389358045    44119592     8      1399635       853369 /usr/src/sys/kern/kern_descrip.c:1990 (filedesc structure)
   146         1629          86    18           28       544914 /usr/src/sys/kern/kern_conf.c:311 (Giant)
991109     37883055     8003082     4       615328       509225 /usr/src/sys/kern/kern_descrip.c:385 (filedesc structure)
 33986     33267790     7972969     4       244622       405542 /usr/src/sys/kern/kern_descrip.c:438 (filedesc structure)
    13        16943        5357     3          475       381640 /usr/src/sys/kern/sys_generic.c:691 (filedesc structure)
Received on Sun May 07 2006 - 17:00:55 UTC

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