Re: [patch 0/7] Add TRIM support for raid linear/0/1/10

[Shaohua Li <shli@kernel.org>]

2012/3/15 Holger Kiehl <Holger.Kiehl@dwd.de>:
> On Wed, 14 Mar 2012, Shaohua Li wrote:
>
>> Maybe the discard runs slow with small size request in the disk.
>> please drop patch "blk: add plug for blkdev_issue_discard" and try again.
>> Since
>> we can't do merge, the plug just introduces latency.
>>
> Tried again without the patch applied, but there is only a very small
> performance increase (520->600 agains 4000 fps without discard).
>
> The benchmark creates lots of small files (2 KiB) and deletes them again.
>
>
>> if it doesn't help, please capture a blktrace when you do the benchmark
>> and
>> send it to me.
>>
> Ok, I will do this tomorrow. Need some sleep :-)
>
> Thanks for your work on supporting discard in MD!
I tried your benchmark, create 2000k 2k files and delete them and
follows a sync.
the discard runs pretty fast for both raid 0/1. So can't reproduce the
issue. I'm using
a fusionio card though. I'm afraid nothing I can do till get you blktrace.

Thanks,
Shaohua