From: Michal Hocko <mhocko@kernel.org>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Rik van Riel <riel@redhat.com>, Mel Gorman <mgorman@suse.de>,
"Huang, Ying" <ying.huang@intel.com>,
Minchan Kim <minchan@kernel.org>,
Vinayak Menon <vinmenon@codeaurora.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 1/2] Revert "mm: make faultaround produce old ptes"
Date: Thu, 16 Jun 2016 17:10:49 +0200 [thread overview]
Message-ID: <20160616151049.GM6836@dhcp22.suse.cz> (raw)
In-Reply-To: <20160616122735.GB108167@black.fi.intel.com>
On Thu 16-06-16 15:27:35, Kirill A. Shutemov wrote:
> On Thu, Jun 16, 2016 at 02:20:02PM +0200, Michal Hocko wrote:
> > On Tue 14-06-16 11:42:29, Kirill A. Shutemov wrote:
> > > This reverts commit 5c0a85fad949212b3e059692deecdeed74ae7ec7.
> > >
> > > The commit causes ~6% regression in unixbench.
> >
> > Is the regression fully explained? My understanding from the email
> > thread is that this is suspiciously too high. It is not like I would
> > be against the revert but having an explanation would be really
> > appreciated.
>
> My understanding is that it's overhead on setting accessed bit:
>
> http://lkml.kernel.org/r/20160613125248.GA30109@black.fi.intel.com
But those numbers cannot explain the regression completely AFAIU. It
smells like something else is going on. Anyway, as I've said I do not
have anything against the revert just more than "unixbench regresses"
would be nice.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2016-06-16 15:11 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-14 8:42 [PATCH 0/2] Reverts to address unixbench regression Kirill A. Shutemov
2016-06-14 8:42 ` [PATCH 1/2] Revert "mm: make faultaround produce old ptes" Kirill A. Shutemov
2016-06-16 12:20 ` Michal Hocko
2016-06-16 12:27 ` Kirill A. Shutemov
2016-06-16 15:10 ` Michal Hocko [this message]
2016-06-14 8:42 ` [PATCH 2/2] Revert "mm: disable fault around on emulated access bit architecture" Kirill A. Shutemov
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