Re: [PATCH v4 2/2] migration/ram: Optimize ram_save_host_page()

[Peter Xu]

On Tue, Mar 16, 2021 at 08:57:16PM +0800, Kunkun Jiang wrote:
> Starting from pss->page, ram_save_host_page() will check every page
> and send the dirty pages up to the end of the current host page or
> the boundary of used_length of the block. If the host page size is
> a huge page, the step "check" will take a lot of time.
> 
> It will improve performance to use migration_bitmap_find_dirty().
> 
> Tested on Kunpeng 920; VM parameters: 1U 4G (page size 1G)
> The time of ram_save_host_page() in the last round of ram saving:
> before optimize: 9250us               after optimize: 34us
> 
> Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
> Signed-off-by: Kunkun Jiang <jiangkunkun@huawei.com>

Reviewed-by: Peter Xu <peterx@redhat.com>

Thanks,

-- 
Peter Xu