Re: [BENCHMARK] 2.5.63-mm2 + i/o schedulers with contest

[Nick Piggin <piggin@cyberone.com.au>]

Con Kolivas wrote:

>Here are contest (http://contest.kolivas.org) benchmarks using the osdl 
>hardware (http://www.osdl.org) for 2.5.63-mm2 and various i/o schedulers:
>
Thanks :)

>It seems the AS scheduler reliably takes slightly longer to compile the kernel 
>in no load conditions, but only about 1% cpu.
>
It is likely that AS will wait too long for gcc to submit another
read and end up timing out anyway. Hopefully IO history tracking
will fix this up - for some loads the effect can be much worse.

>
>
>CFQ and DL faster to compile the kernel than AS while extracting or creating 
>tars.
>
This is likely to be balancing differences from LCPU% it does
seem like AS is doing a bit more "load" work.

>
>
>AS significantly faster under writing large file to the same disk (io_load) or 
>other disk (io_other) conditions. The CFQ and DL schedulers showed much more 
>variability on io_load during testing but did not drop below 140 seconds.
>
small randomish reads vs large writes _is_ where AS really can
perform better than non a non AS scheduler. Unfortunately gcc
doesn't have the _best_ IO pattern for AS ;)

>
>
>CFQ and DL scheduler were faster compiling the kernel under read_load,  
>list_load and dbench_load.
>
>Mem_load result of AS being slower was just plain weird with the result rising 
>from 100 to 150 during testing.
>
I would like to see if AS helps much with a swap/memory
thrashing load.