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From: Maxime Coquelin <maxime.coquelin@redhat.com>
To: dev@dpdk.org, jianfeng.tan@intel.com, tiwei.bie@intel.com,
	jfreimann@redhat.com
Cc: stable@dpdk.org
Subject: Re: [dpdk-dev] [PATCH] vhost: avoid concurrency when logging dirty pages
Date: Fri, 30 Mar 2018 09:42:39 +0200	[thread overview]
Message-ID: <efab884b-0322-13f4-c842-65ee5cddec21@redhat.com> (raw)
In-Reply-To: <20180321154413.1120-1-maxime.coquelin@redhat.com>



On 03/21/2018 04:44 PM, Maxime Coquelin wrote:
> This patch aims at fixing a migration performance regression
> faced since atomic operation is used to log pages as dirty when
> doing live migration.
> 
> Instead of setting a single bit by doing an atomic read-modify-write
> operation to log a page as dirty, this patch write 0xFF to the
> corresponding byte, and so logs 8 page as dirty.
> 
> The advantage is that it avoids concurrent atomic operations by
> multiple PMD threads, the drawback is that some clean pages are
> marked as dirty and so are transferred twice.
> 
> Fixes: 897f13a1f726 ("vhost: make page logging atomic")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>   lib/librte_vhost/vhost.h | 12 ++++--------
>   1 file changed, 4 insertions(+), 8 deletions(-)

Applied to dpdk-next-virtio/master.

      parent reply	other threads:[~2018-03-30  7:42 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-21 15:44 Maxime Coquelin
2018-03-27  1:15 ` Tan, Jianfeng
2018-03-27 11:24   ` Maxime Coquelin
2018-03-30  7:42 ` Maxime Coquelin [this message]

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