On Wed, May 16, 2018 at 06:54:23PM +0200, Maxime Coquelin wrote:
> This patch caches all dirty pages logging until the used ring index
> is updated.
>
> The goal of this optimization is to fix a performance regression
> introduced when the vhost library started to use atomic operations
> to set bits in the shared dirty log map. While the fix was valid
> as previous implementation wasn't safe against concurent accesses,
Typo: concurent
> contention was induced.
>
> With this patch, during migration, we have:
> 1. Less atomic operations as only a single atomic OR operation
> per 32 or 64 (depending on CPU) pages.
> 2. Less atomic operations as during a burst, the same page will
> be marked dirty only once.
> 3. Less write memory barriers.
>
> Fixes: 897f13a1f726 ("vhost: make page logging atomic")
>
> Cc: sta...@dpdk.org
>
> Cc: Tiwei Bie <tiwei....@intel.com>
> Suggested-by: Michael S. Tsirkin <m...@redhat.com>
> Signed-off-by: Maxime Coquelin <maxime.coque...@redhat.com>
Apart from the typo,
Reviewed-by: Tiwei Bie <tiwei....@intel.com>
