Re: Weird trim test results

[Jens Axboe <axboe@kernel.dk>]

Please don't top post...

On 07/25/2013 11:27 AM, Matthew Eaton wrote:
> Hi Jens,
> 
> I'm running Ubuntu 12.04.2, my kernel is:
> 
> Linux matt-work 3.5.0-36-generic #57~precise1-Ubuntu SMP Thu Jun 20
> 18:21:09 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
> 
> Here is the output I got from blktrace / blkparse:
> 
> Total (sdb):
>  Reads Queued:         166,      664KiB     Writes Queued:
> 3001,    12004KiB
>  Read Dispatches:      166,      664KiB     Write Dispatches:
> 3001,    12004KiB
>  Reads Requeued:         0         Writes Requeued:         0
>  Reads Completed:      166,      664KiB     Writes Completed:
> 3001,     1500KiB
>  Read Merges:            0,        0KiB     Write Merges:
> 0,        0KiB
>  PC Reads Queued:        0,        0KiB     PC Writes Queued:
> 0,        0KiB
>  PC Read Disp.:         22,        3KiB     PC Write Disp.:
> 0,        0KiB
>  PC Reads Req.:          0         PC Writes Req.:          0
>  PC Reads Compl.:       10         PC Writes Compl.:        0
>  IO unplugs:           166             Timer unplugs:           0

That looks fine, it might just be coincidence that you are capped at
~100 IOPS. I don't think it's that unlikely that the this is the limit
for you, your device might have a fixed overhead associated with a trim
request. I'd have to look closer at your system to see if that's the
case or not.

-- 
Jens Axboe