From: Stefan Hajnoczi <stefanha@gmail.com>
To: Fam Zheng <famz@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
qemu-devel@nongnu.org, qemu-block@nongnu.org
Subject: Re: [Qemu-devel] [Qemu-block] [PATCH 0/3] mirror: Fix guest responsiveness during bitmap scan
Date: Thu, 9 Jul 2015 14:02:08 +0100 [thread overview]
Message-ID: <20150709130208.GD11166@stefanha-thinkpad.redhat.com> (raw)
In-Reply-To: <1436413678-7114-1-git-send-email-famz@redhat.com>
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On Thu, Jul 09, 2015 at 11:47:55AM +0800, Fam Zheng wrote:
> This supersedes:
>
> http://patchwork.ozlabs.org/patch/491415/
>
> and [1] which is currently in Jeff's tree.
>
> Although [1] fixed the QMP responsiveness, Alexandre DERUMIER reported that
> guest responsiveness still suffers when we are busy in the initial dirty bitmap
> scanning loop of mirror job. That is because 1) we issue too many lseeks; 2) we
> only sleep for 0 ns which turns out quite ineffective in yielding BQL to vcpu
> threads. Both are fixed.
>
> To reproduce: start a guest, attach a 10G raw image, then mirror it. Your
> guest will immediately start to stutter (with patch [1] testing on a local ext4
> raw image, and "while echo -n .; do sleep 0.05; done" in guest console).
>
> This series adds block_job_relax_cpu as suggested by Stefan Hajnoczi and uses
> it in mirror job; and lets bdrv_is_allocated_above return a larger p_num as
> suggested by Paolo Bonzini (although it's done without changing the API).
>
> [1]: http://patchwork.ozlabs.org/patch/471656/ "block/mirror: Sleep
> periodically during bitmap scanning"
>
> Fam Zheng (3):
> blockjob: Introduce block_job_relax_cpu
> mirror: Use block_job_relax_cpu during bitmap scanning
> mirror: Speed up bitmap initial scanning
>
> block/mirror.c | 17 +++++++----------
> include/block/blockjob.h | 16 ++++++++++++++++
> 2 files changed, 23 insertions(+), 10 deletions(-)
This patch only converts the mirror block job to use the new relax
function. The other block jobs (stream, backup, commit) are still using
a 0 ns delay and are therefore broken. They should probably be
converted in the same series.
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next prev parent reply other threads:[~2015-07-09 13:02 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-09 3:47 [Qemu-devel] [PATCH 0/3] mirror: Fix guest responsiveness during bitmap scan Fam Zheng
2015-07-09 3:47 ` [Qemu-devel] [PATCH 1/3] blockjob: Introduce block_job_relax_cpu Fam Zheng
2015-07-09 12:54 ` [Qemu-devel] [Qemu-block] " Stefan Hajnoczi
2015-07-10 3:42 ` Alexandre DERUMIER
2015-07-14 12:31 ` Stefan Hajnoczi
2015-07-15 10:32 ` Fam Zheng
2015-07-16 13:21 ` Stefan Hajnoczi
2015-07-09 3:47 ` [Qemu-devel] [PATCH 2/3] mirror: Use block_job_relax_cpu during bitmap scanning Fam Zheng
2015-07-09 13:00 ` [Qemu-devel] [Qemu-block] " Stefan Hajnoczi
2015-07-09 3:47 ` [Qemu-devel] [PATCH 3/3] mirror: Speed up bitmap initial scanning Fam Zheng
2015-07-09 13:00 ` Stefan Hajnoczi
2015-07-14 13:21 ` Stefan Hajnoczi
2015-07-09 11:51 ` [Qemu-devel] [PATCH 0/3] mirror: Fix guest responsiveness during bitmap scan Alexandre DERUMIER
2015-07-09 13:02 ` Stefan Hajnoczi [this message]
2015-07-09 13:18 ` [Qemu-devel] [Qemu-block] " Alexandre DERUMIER
2015-07-10 6:43 ` Fam Zheng
2015-07-10 6:54 ` Alexandre DERUMIER
2015-07-10 7:13 ` Fam Zheng
2015-07-10 10:36 ` Alexandre DERUMIER
2015-07-10 12:16 ` Alexandre DERUMIER
2015-07-13 5:08 ` Fam Zheng
2015-07-14 12:40 ` Stefan Hajnoczi
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