Hi, Tsuruta-san,

Thanks for your test.

quoted text
> 
> Uchida-san said,
> 
> > In the test #2 and #3, did you use direct write?
> > I guess you have used the non-direct write I/O (using cache).
> 
> I answered "Yes," but actually I did not use direct write I/O, because
> I ran these tests on Xen-HVM. Xen-HVM backend driver doesn't use direct
> I/O for actual disk operations even though guest OS uses direct I/O.
> 

Where did you build expanded CFQ schedulers?
I guess that schedulers can be control I/Os if it is built on guest OS,
But not if on Dom0.
I guess you built on Dom0 so that you could not control I/O. (maybe, you say)


quoted text
> So, I retested with the new testing environment and got good results.
> The number of I/Os is proportioned according to the priority levels.
>

Ok.
I'm testing both systems and get similar results.
I will report my test in next week.



quoted text
> Details of the tests are as follows:
> 
> Envirionment:
>   Linux version 2.6.25-rc2-mm1 based.
>   CPU0: Intel(R) Core(TM)2 CPU          6600  @ 2.40GHz stepping 06
>   CPU1: Intel(R) Core(TM)2 CPU          6600  @ 2.40GHz stepping 06
>   Memory: 2063568k/2088576k available (2085k kernel code, 23684k
>   reserved, 911k data, 240k init, 1171072k highmem)
>   scsi 1:0:0:0: Direct-Access     ATA      WDC WD2500JS-55N 10.0 PQ: 0
> ANSI: 5
>   sd 1:0:0:0: [sdb] 488397168 512-byte hardware sectors (250059 MB)
>   sd 1:0:0:0: [sdb] Write Protect is off
>   sd 1:0:0:0: [sdb] Mode Sense: 00 3a 00 00
>   sd 1:0:0:0: [sdb] Write cache: disabled, read cache: enabled,
>   doesn't support DPO or FUA
>   sdb: sdb1 sdb2 sdb3 sdb4 < sdb5 sdb6 sdb7 sdb8 sdb9 sdb10 sdb11
>   sdb12 sdb13 sdb14 sdb15 >
> 
> Procedures:
>   o Prepare 3 partitions sdb5, sdb6 and sdb7.
>   o Run 100 processes issuing random direct I/O with 4KB data on each
>     partitions.
>   o Run 3 tests:
>     #1 issuing read I/O only.
>     #2 issuing write I/O only.
>     #3 sdb5 and sdb6 are read, sdb7 is write.
>   o Count up the number of I/Os which have done in 60 seconds.
> 
> Results:
>                           Vasily's scheduler
>                The number of I/Os (percentage to total I/Os)
> 
> ---------------------------------------------------------------------
>   | partition     |     sdb5     |     sdb6     |     sdb7     | total
> |
>   | priority      |  7(highest)  |      4       |  0(lowest)   |  I/Os
> |
> 
> |---------------+--------------+--------------+--------------|--------
> |
>   | #1 read       |   3383(35%)  |   3164(33%)  |   3142(32%)  |  9689
> |
>   | #2 write      |   3017(42%)  |   2372(33%)  |   1851(26%)  |  7240
> |
>   | #3 read&write |   4300(36%)  |   3127(27%)  |   1521(17%)  |  8948
> |
> 
> ---------------------------------------------------------------------
> 
>                           Satoshi's scheduler
>                The number of I/Os (percentage to total I/O)
> 
> ---------------------------------------------------------------------
>   | partition     |     sdb5     |     sdb6     |     sdb7     | total
> |
>   | priority      |  0(highest)  |      4       |  7(lowest)   |  I/Os
> |
> 
> |---------------+--------------+--------------+--------------|--------
> |
>   | #1 read       |   3907(47%)  |   3126(38%)  |   1260(15%)  |  8293
> |
>   | #2 write      |   3389(41%)  |   3024(36%)  |   1901(23%)  |  8314
> |
>   | #3 read&write |   5028(53%)  |   3961(42%)  |    441( 5%)  |  9430
> |
> 
> ---------------------------------------------------------------------
> 
> Thanks,
> Ryo Tsuruta

Thanks,
Satoshi UCHIDA.


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