Messages in this thread | | | Date | Sun, 01 Aug 2010 11:18:12 +0300 | From | Avi Kivity <> | Subject | Re: [RFC PATCH v8 00/16] Provide a zero-copy method on KVM virtio-net. |
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On 07/30/2010 06:46 PM, Shirley Ma wrote: > Hello Avi, > > On Fri, 2010-07-30 at 08:02 +0300, Avi Kivity wrote: >> get_user_pages() is indeed slow. But what about >> get_user_pages_fast()? >> >> Note that when the page is first touched, get_user_pages_fast() falls >> back to get_user_pages(), so the latency needs to be measured after >> quite a bit of warm-up. > Yes, I used get_user_pages_fast, however if falled back to > get_user_pages() when the apps doesn't allocate buffer on the same page. > If I run a single ping, the RTT is extremely high, but when running > multiple pings, the RTT time reduce significantly, but still it is not > as fast as copy from my initial test. I am thinking that we might need > to pre-pin memory pool. >
I don't understand. Under what conditions do you use get_user_pages() instead of get_user_pages_fast()? Why?
-- error compiling committee.c: too many arguments to function
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