Re: 2.6.4-mm2

[Andrew Morton]

Mary Edie Meredith <maryedie@xxxxxxxx> wrote:
>
> [was "Poor DBT-3 pgsql 8way numbers on recent 2.6 mm kernels" on
> linux-mm]
> 
> Andrew,
> 
> This same patch (02) applied in STP (plm 2780) when run against
> dbt3-pgsql DSS workload displays the performance problem with the
> throughput numbers that I reported on linux-mm on our 8way systems,
> where the previous patch (plm 2777 -01) does not.  
> 
> Here is the data (patches applied to 2.6.5-rc1)
> 
> PLM.....CPUs.Runid..Thruput Metric (bigger is better)
> 2777(01)  8  290298  138.22  (base  )
> 2779(02)  8  290304  88.57   (-35.9%)

36% regression due to the CPU scheduler changes?  ow.

And that machine is a PIII, so presumably the setting of CONFIG_SCHED_SMT
makes no difference.

>From a quick look at the material you have there it appears that this
workload also is very I/O bound.  It's a little surprising that the CPU
scheduler could make so much difference.

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