Re: [Qemu-devel] [PATCH 06/10] migraion: optimiztion xbzrle by reducing data copy

[Eric Blake <eblake@redhat.com>]

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On 03/11/2014 06:53 AM, arei.gonglei@huawei.com wrote:
> From: ChenLiang <chenliang88@huawei.com>

s/migraion/migration/ in the subject (here and in 7/10)

s/optimiztion/optimize/ in the subject

> +++ b/arch_init.c
> @@ -381,11 +381,8 @@ static int save_xbzrle_page(QEMUFile *f, uint8_t **current_data,
>  
>      prev_cached_page = get_cached_data(XBZRLE.cache, current_addr);
>  
> -    /* save current buffer into memory */
> -    memcpy(XBZRLE.current_buf, *current_data, TARGET_PAGE_SIZE);
> -
>      /* XBZRLE encoding (if there is no overflow) */
> -    encoded_len = xbzrle_encode_buffer(prev_cached_page, XBZRLE.current_buf,
> +    encoded_len = xbzrle_encode_buffer(prev_cached_page, *current_data,
>                                         TARGET_PAGE_SIZE, XBZRLE.encoded_buf,
>                                         TARGET_PAGE_SIZE);
>      if (encoded_len == 0) {
> @@ -404,7 +401,8 @@ static int save_xbzrle_page(QEMUFile *f, uint8_t **current_data,
>  
>      /* we need to update the data in the cache, in order to get the same data */
>      if (!last_stage) {
> -        memcpy(prev_cached_page, XBZRLE.current_buf, TARGET_PAGE_SIZE);
> +        xbzrle_decode_buffer(XBZRLE.encoded_buf, encoded_len, prev_cached_page,
> +                             TARGET_PAGE_SIZE);

So, is XBZRLE.current_buf even needed after this patch?  Oh, patch 7
kills it.  I guess splitting in two patches is okay, although I
personally would have squashed them into one.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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