On Mon, Feb 26, 2007 at 02:57:36PM +0100, Jens Axboe wrote:
quoted text
> 
> Some more results, using a larger number of processes and io depths. A
> repeat of the tests from friday, with added depth 20000 for syslet and
> libaio:
> 
> Engine          Depth   Processes       Bw (MiB/sec)
> ----------------------------------------------------
> libaio            1         1            602
> syslet            1         1            759
> sync              1         1            776
> libaio           32         1            832
> syslet           32         1            898
> libaio        20000         1            581
> syslet        20000         1            609
> 
> syslet still on top. Measuring O_DIRECT reads (of 4kb size) on ramfs
> with 100 processes each with a depth of 200, reading a per-process
> private file of 10mb (need to fit in my ram...) 10 times each. IOW,
> doing 10,000MiB of IO in total:

But, why ramfs ? Don't we want to exercise the case where O_DIRECT actually
blocks ? Or am I missing something here ?

Regards
Suparna

quoted text
> 
> Engine          Depth   Processes       Bw (MiB/sec)
> ----------------------------------------------------
> libaio           200       100            1488
> syslet           200       100            1714
> 
> Results are stable to within approx +/- 10MiB/sec. The syslet case
> completes a whole second faster than libaio (~6 vs ~7 seconds). Testing
> was done with fio HEAD eb7c8ae27bc301b77490b3586dd5ccab7c95880a, and it
> uses the v4 patch series.
> 
> Engine          Depth   Processes       Bw (MiB/sec)
> ----------------------------------------------------
> libaio            200       100            1488
> syslet            200       100            1714
> sync              200       100            1843
> 
> -- 
> Jens Axboe

-- 
Suparna Bhattacharya (suparna@in.ibm.com)
Linux Technology Center
IBM Software Lab, India

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