Date: Fri, 24 Oct 2014 09:54:23 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>,
        "Kirill A. Shutemov" <kirill@shutemov.name>,
        torvalds@linux-foundation.org, paulmck@linux.vnet.ibm.com,
        tglx@linutronix.de, akpm@linux-foundation.org, riel@redhat.com,
        mgorman@suse.de, oleg@redhat.com, mingo@redhat.com, minchan@kernel.org,
        kamezawa.hiroyu@jp.fujitsu.com, viro@zeniv.linux.org.uk,
        dave@stgolabs.net, linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [RFC][PATCH 0/6] Another go at speculative page faults
Message-ID: <20141024075423.GA24479@gmail.com>
References: <20141020215633.717315139@infradead.org>
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 <20141021175603.GI3219@twins.programming.kicks-ass.net>
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* Peter Zijlstra <peterz@infradead.org> wrote:

> On Thu, Oct 23, 2014 at 06:40:05PM +0800, Lai Jiangshan wrote:
> > On 10/22/2014 01:56 AM, Peter Zijlstra wrote:
> > > On Tue, Oct 21, 2014 at 08:09:48PM +0300, Kirill A. Shutemov wrote:
> > >> It would be interesting to see if the patchset affects non-condended case.
> > >> Like a one-threaded workload.
> > > 
> > > It does, and not in a good way, I'll have to look at that... :/
> > 
> > Maybe it is blamed to find_vma_srcu() that it doesn't take the advantage of
> > the vmacache_find() and cause more cache-misses.
> 
> Its what I thought initially, I tried doing perf record with and
> without, but then I ran into perf diff not quite working for me and I've
> yet to find time to kick that thing into shape.

Might be the 'perf diff' regression fixed by this:

  9ab1f50876db perf diff: Add missing hists__init() call at tool start

I just pushed it out into tip:master.

Thanks,

	Ingo
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