Subject: Re: [Xen-devel] [PATCH 0/4] Implement persistent grant in xen-netfront/netback

From: ANNIE LI <[email-masked]>
Date: Thu, 15 Nov 2012 19:14:12 +0800

On 2012-11-15 18:56, Roger Pau Monné wrote:
> On 15/11/12 09:38, ANNIE LI wrote:
>>
>> On 2012-11-15 15:40, Pasi Kärkkäinen wrote:
>>> Hello,
>>>
>>> On Thu, Nov 15, 2012 at 03:03:07PM +0800, Annie Li wrote:
>>>> This patch implements persistent grants for xen-netfront/netback. This
>>>> mechanism maintains page pools in netback/netfront, these page pools is used to
>>>> save grant pages which are mapped. This way improve performance which is wasted
>>>> when doing grant operations.
>>>>
>>>> Current netback/netfront does map/unmap grant operations frequently when
>>>> transmitting/receiving packets, and grant operations costs much cpu clock. In
>>>> this patch, netfront/netback maps grant pages when needed and then saves them
>>>> into a page pool for future use. All these pages will be unmapped when
>>>> removing/releasing the net device.
>>>>
>>> Do you have performance numbers available already? with/without persistent grants?
>> I have some simple netperf/netserver test result with/without persistent
>> grants,
>>
>> Following is result of with persistent grant patch,
>>
>> Guests, Sum,      Avg,     Min,     Max
>>    1,  15106.4,  15106.4, 15106.36, 15106.36
>>    2,  13052.7,  6526.34,  6261.81,  6790.86
>>    3,  12675.1,  6337.53,  6220.24,  6454.83
>>    4,  13194,  6596.98,  6274.70,  6919.25
>>
>>
>> Following are result of without persistent patch
>>
>> Guests, Sum,     Avg,    Min,        Max
>>    1,  10864.1,  10864.1, 10864.10, 10864.10
>>    2,  10898.5,  5449.24,  4862.08,  6036.40
>>    3,  10734.5,  5367.26,  5261.43,  5473.08
>>    4,  10924,    5461.99,  5314.84,  5609.14
> In the block case, performance improvement is seen when using a large
> number of guests, could you perform the same benchmark increasing the
> number of guests to 15?
Sure, but my current local environment does not meet such test 
requirement, let me find an environment and then start such test.

Thanks
Annie