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SubjectRe: [PATCH v3 0/5] Rework mtime and ctime updates on mmaped writes
On Wed, Sep 4, 2013 at 8:08 AM, Jan Kara <jack@suse.cz> wrote:
> On Thu 22-08-13 17:03:16, Andy Lutomirski wrote:
>> Writes via mmap currently update mtime and ctime in ->page_mkwrite.
>> This hurts both throughput and latency. In workloads that dirty a
>> large number of mmapped pages, ->page_mkwrite can be hot and
>> file_update_time is slow and scales poorly. Updating timestamps can
>> also sleep, which hurts latency for real-time workloads.
> It would help to make your case if you posted the latency comparison
> before & after the patchset in this introductory email. We can then see
> how significant is the reduction of latency...

Will do, although the data from my workload will be a little strange.

I was hoping that Dave Hansen would re-run his benchmark with these
patches applied. I tried to run it, but it wasn't obvious what the
numbers that spewed out meant.

--Andy

>
> Honza
> --
> Jan Kara <jack@suse.cz>
> SUSE Labs, CR



--
Andy Lutomirski
AMA Capital Management, LLC


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