From: Mel Gorman <mgorman@suse.de>
To: Richard Davies <richard@arachsys.com>
Cc: KVM <kvm@vger.kernel.org>, QEMU-devel <qemu-devel@nongnu.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>, Avi Kivity <avi@redhat.com>,
Shaohua Li <shli@kernel.org>
Subject: Re: [Qemu-devel] [PATCH 0/6] Reduce compaction scanning and lock contention
Date: Fri, 21 Sep 2012 10:35:30 +0100 [thread overview]
Message-ID: <20120921093530.GS11266@suse.de> (raw)
In-Reply-To: <20120921091333.GA32081@alpha.arachsys.com>
On Fri, Sep 21, 2012 at 10:13:33AM +0100, Richard Davies wrote:
> Hi Mel,
>
> Thank you for this series. I have applied on clean 3.6-rc5 and tested, and
> it works well for me - the lock contention is (still) gone and
> isolate_freepages_block is much reduced.
>
Excellent!
> Here is a typical test with these patches:
>
> # grep -F '[k]' report | head -8
> 65.20% qemu-kvm [kernel.kallsyms] [k] clear_page_c
> 2.18% qemu-kvm [kernel.kallsyms] [k] isolate_freepages_block
> 1.56% qemu-kvm [kernel.kallsyms] [k] _raw_spin_lock
> 1.40% qemu-kvm [kernel.kallsyms] [k] svm_vcpu_run
> 1.38% swapper [kernel.kallsyms] [k] default_idle
> 1.35% qemu-kvm [kernel.kallsyms] [k] get_page_from_freelist
> 0.74% ksmd [kernel.kallsyms] [k] memcmp
> 0.72% qemu-kvm [kernel.kallsyms] [k] free_pages_prepare
>
Ok, so that is more or less acceptable. I would like to reduce the scanning
even further but I'll take this as a start -- largely because I do not have
any new good ideas on how it could be reduced further without incurring
a large cost in the page allocator :)
> I did manage to get a couple which were slightly worse, but nothing like as
> bad as before. Here are the results:
>
> # grep -F '[k]' report | head -8
> 45.60% qemu-kvm [kernel.kallsyms] [k] clear_page_c
> 11.26% qemu-kvm [kernel.kallsyms] [k] isolate_freepages_block
> 3.21% qemu-kvm [kernel.kallsyms] [k] _raw_spin_lock
> 2.27% ksmd [kernel.kallsyms] [k] memcmp
> 2.02% swapper [kernel.kallsyms] [k] default_idle
> 1.58% qemu-kvm [kernel.kallsyms] [k] svm_vcpu_run
> 1.30% qemu-kvm [kernel.kallsyms] [k] _raw_spin_lock_irqsave
> 1.09% qemu-kvm [kernel.kallsyms] [k] get_page_from_freelist
>
> # grep -F '[k]' report | head -8
> 61.29% qemu-kvm [kernel.kallsyms] [k] clear_page_c
> 4.52% qemu-kvm [kernel.kallsyms] [k] _raw_spin_lock_irqsave
> 2.64% qemu-kvm [kernel.kallsyms] [k] copy_page_c
> 1.61% swapper [kernel.kallsyms] [k] default_idle
> 1.57% qemu-kvm [kernel.kallsyms] [k] _raw_spin_lock
> 1.18% qemu-kvm [kernel.kallsyms] [k] get_page_from_freelist
> 1.18% qemu-kvm [kernel.kallsyms] [k] isolate_freepages_block
> 1.11% qemu-kvm [kernel.kallsyms] [k] svm_vcpu_run
>
>
Were the boot times acceptable even when these slightly worse figures
were recorded?
> I will follow up with the detailed traces for these three tests.
>
> Thank you!
>
Thank you for the detailed reporting and the testing, it's much
appreciated. I've already rebased the patches to Andrew's tree and tested
them overnight and the figures look good on my side. I'll update the
changelog and push them shortly.
--
Mel Gorman
SUSE Labs
next prev parent reply other threads:[~2012-09-21 9:35 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-20 14:04 [Qemu-devel] [PATCH 0/6] Reduce compaction scanning and lock contention Mel Gorman
2012-09-20 14:04 ` [Qemu-devel] [PATCH 1/6] mm: compaction: Abort compaction loop if lock is contended or run too long Mel Gorman
2012-09-20 18:53 ` Rik van Riel
2012-09-20 14:04 ` [Qemu-devel] [PATCH 2/6] mm: compaction: Acquire the zone->lru_lock as late as possible Mel Gorman
2012-09-20 18:54 ` Rik van Riel
2012-09-20 14:04 ` [Qemu-devel] [PATCH 3/6] mm: compaction: Acquire the zone->lock " Mel Gorman
2012-09-20 18:54 ` Rik van Riel
2012-09-20 14:04 ` [Qemu-devel] [PATCH 4/6] Revert "mm: have order > 0 compaction start off where it left" Mel Gorman
2012-09-20 18:54 ` Rik van Riel
2012-09-20 14:04 ` [Qemu-devel] [PATCH 5/6] mm: compaction: Cache if a pageblock was scanned and no pages were isolated Mel Gorman
2012-09-20 18:55 ` Rik van Riel
2012-09-20 14:04 ` [Qemu-devel] [PATCH 6/6] mm: compaction: Restart compaction from near where it left off Mel Gorman
2012-09-20 18:57 ` Rik van Riel
2012-09-21 9:13 ` [Qemu-devel] [PATCH 0/6] Reduce compaction scanning and lock contention Richard Davies
2012-09-21 9:15 ` Richard Davies
2012-09-21 9:17 ` Richard Davies
2012-09-21 9:55 ` Mel Gorman
2012-09-21 9:18 ` Richard Davies
2012-09-21 9:35 ` Mel Gorman [this message]
2012-09-21 9:49 ` Richard Davies
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20120921093530.GS11266@suse.de \
--to=mgorman@suse.de \
--cc=avi@redhat.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=qemu-devel@nongnu.org \
--cc=richard@arachsys.com \
--cc=shli@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).