Messages in this thread | | | From | Vitaly Kuznetsov <> | Subject | Re: Backport request to stable of two performance related fixes for xen-blkfront (3.13 fixes to earlier trees) | Date | Fri, 06 Jun 2014 12:58:20 +0200 |
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Jiri Slaby <jslaby@suse.cz> writes:
> On 06/04/2014 07:48 AM, Greg KH wrote: >> On Wed, May 14, 2014 at 03:11:22PM -0400, Konrad Rzeszutek Wilk wrote: >>> Hey Greg >>> >>> This email is in regards to backporting two patches to stable that >>> fall under the 'performance' rule: >>> >>> bfe11d6de1c416cea4f3f0f35f864162063ce3fa >>> fbe363c476afe8ec992d3baf682670a4bd1b6ce6 >> >> Now queued up, thanks. > > AFAIU, they introduce a performance regression. > > Vitaly?
I'm aware of a performance regression in a 'very special' case when ramdisks or files on tmpfs are being used as storage, I post my results a while ago: https://lkml.org/lkml/2014/5/22/164 I'm not sure if that 'special' case requires investigation and/or should prevent us from doing stable backport but it would be nice if someone tries to reproduce it at least.
I'm going to make a bunch of tests with FusionIO drives and sequential read to replicate same test Felipe did, I'll report as soon as I have data (beginning of next week hopefuly).
-- Vitaly
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