Re: [Qemu-devel] [PATCH 0/7] migration: Optimization the xbzrle and fix two corruption issues

[Gonglei <arei.gonglei@huawei.com>]

On 2014/2/28 17:19, Dr. David Alan Gilbert wrote:

> * Gonglei (Arei) (arei.gonglei@huawei.com) wrote:
> 
> Hi,
> 
>> a. Optimization the xbzrle remarkable decrease the cache misses.
>>     The efficiency of compress increases more than fifty times.
>>     Before the patch set, the cache almost totally miss when the 
>>     number of cache item less than the dirty page number. Now the
>>     hot pages in the cache will not be replaced by other pages. 
> 
> Nice, what do you use as your performance test case for xbzrle?


The VM we used with 25G memory and 1Gbit nic. We run a test procedure
in the vm, which as this:

#include <stdio.h>
#include <stdlib.h>
#define PAGE_SIZE 4096
void main(void)
{
    char *p,*p1;
    long i,j,z;

    p = (char*)calloc(8*1024,1024*1024);
    if( p == NULL ){
        printf("fail to calloc \n");
        exit(1);
    }
    for(;;){
        p1 = p;
        for( i = 0 ; i < 8*1024 ; i++ ){

            for( j = 0 ; j < 1024*1024 ; j+=PAGE_SIZE ){
               *p1 = 0x55;
               p1+=PAGE_SIZE;
            }
        }
    }
}

finally,
the results of without enable xbzrle: 115MB/sec

using xbzrle without optimization (the size of cache 2G): 116MB/sec

using xbzrle with our optimization (the size of cache 2G): 150MB/sec

> 
> Dave
> --
> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK


Best regards,
-Gonglei