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From:Yusuf Goolamabbas Date:January 19 2005 7:42am
Subject:Re: Comparing Linux 2.6/2.4 with read-only sysbench workload with complex point selects on myisam table
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> Could you please send me the log in separate Email I'll let our
> production team know.  It is not that common version nowadays but
> anyway.

I'll try to compile 4.1.9 and send the error messages if any

> > The anticipatory scheduler was used on 2.6 kernels and the tag depth of
> > the aic7xxx controller was clamped at 4 via the following modprobe.conf
> > command line
> > 
> > options aic7xxx aic7xxx=global_tag_depth:4
> 
> Why did you reduce TCQ Depth ? 

Nick Piggin has mentioned it on lkml that AS with high TCQ doesn't work
well. For Database servers, it's recommended to use deadline. See
Documentation/block/as-iosched.txt in the linux-kernel source tree. I
got similar numbers with deadline and default tag depth of 32

I'll try to setup a RAID 10 disk mirror and then re-run the same tests
with deadline/cfq/as. 

> Yes.  2.6 kernel seems to do much better. It is however barely depending
> on IO subsystem as default table size is just 10000 rows so it will well
> fit in memory. 

I changed the table size to 100000 rows. If/When I get a faster i/o
system on the boxes. I'll try with even larger table sizes. 

> Very interesting.   2.6 kernel runs very fast but it allows some threads
> to starve - so you can see higher average response time as well as much
> higher 95% percentile response time.   Also  Thread fairness is pretty
> poor - this parameters measure what is the difference between number of
> requests threads was able to get. In perfect case it should be close 100
> meaning all threads processed about same number of requests. 

Thread
Comparing Linux 2.6/2.4 with read-only sysbench workload with complex point selects on myisam tableYusuf Goolamabbas19 Jan
  • Re: Comparing Linux 2.6/2.4 with read-only sysbench workload withcomplex point selects on myisam tablePeter Zaitsev19 Jan
    • Re: Comparing Linux 2.6/2.4 with read-only sysbench workload with complex point selects on myisam tableYusuf Goolamabbas19 Jan
      • Re: Comparing Linux 2.6/2.4 with read-only sysbench workload withcomplex point selects on myisam tablePeter Zaitsev19 Jan