From: Avi Kivity <avi@qumranet.com>
To: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Cc: Rusty Russell <rusty@rustcorp.com.au>,
Ingo Molnar <mingo@elte.hu>,
kvm-devel@lists.sourceforge.net, netdev <netdev@vger.kernel.org>
Subject: Re: [kvm-devel] QEMU PIC indirection patch for in-kernel APIC work
Date: Tue, 10 Apr 2007 15:17:45 +0300 [thread overview]
Message-ID: <461B8069.6070007@qumranet.com> (raw)
In-Reply-To: <20070410115035.GA2247@2ka.mipt.ru>
Evgeniy Polyakov wrote:
>> This is what Xen does. It is actually less performant than copying, IIRC.
>>
>> The problem with flipping pages around is that physical addresses are
>> cached both in the kvm mmu and in the on-chip tlbs, necessitating
>> expensive page table walks and tlb invalidation IPIs.
>>
>
> Hmm, I'm not familiar with Xen driver, but similar technique was used
> with zero-copy network sniffer some time ago, substituting userspace
> pages with pages containing skb data was about 25-50% faster than
> copying 1500 bytes in general, and in order of 10 times faster in some
> cases.
>
> Check a link please in case we are talking about different ideas:
> http://marc.info/?l=linux-netdev&m=112262743505711&w=2
>
>
I don't really understand what you're testing there. in particular, how
can the copying time change so dramatically depending on whether you've
just rebooted or not?
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2007-04-10 12:17 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <4613B438.60107@codemonkey.ws>
[not found] ` <4613B89F.8090806@qumranet.com>
[not found] ` <4613BC6B.1070708@codemonkey.ws>
[not found] ` <4613BF07.50606@qumranet.com>
[not found] ` <4613C993.9020405@codemonkey.ws>
[not found] ` <4613CC01.1090500@qumranet.com>
[not found] ` <4613CDB2.4000903@codemonkey.ws>
[not found] ` <4613D001.3040606@qumranet.com>
[not found] ` <20070404200112.GA6070@elte.hu>
[not found] ` <4614098F.2030307@us.ibm.com>
[not found] ` <20070404212103.GA19026@elte.hu>
2007-04-04 23:19 ` [kvm-devel] QEMU PIC indirection patch for in-kernel APIC work Rusty Russell
2007-04-05 7:17 ` Avi Kivity
2007-04-06 1:02 ` Rusty Russell
2007-04-08 5:36 ` Avi Kivity
[not found] ` <46187F4E.1080807-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-04-08 9:04 ` Muli Ben-Yehuda
2007-04-09 2:50 ` Rusty Russell
[not found] ` <1176087018.11664.65.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2007-04-09 7:10 ` Avi Kivity
[not found] ` <4619E6DC.3010804-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-04-09 9:46 ` Rusty Russell
[not found] ` <1176111984.11664.90.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2007-04-09 13:38 ` Avi Kivity
[not found] ` <461A41CA.9080201-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-04-10 8:07 ` Evgeniy Polyakov
2007-04-10 8:19 ` [kvm-devel] " Avi Kivity
[not found] ` <461B48A8.1060904-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-04-10 8:58 ` Evgeniy Polyakov
2007-04-10 11:21 ` [kvm-devel] " Avi Kivity
[not found] ` <461B7334.8090807-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-04-10 11:50 ` Evgeniy Polyakov
2007-04-10 12:17 ` Avi Kivity [this message]
[not found] ` <461B8069.6070007-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-04-10 12:30 ` Evgeniy Polyakov
[not found] ` <20070410123034.GA11493-9fLWQ3dKdXwox3rIn2DAYQ@public.gmane.org>
2007-04-10 12:49 ` Avi Kivity
2007-04-11 3:53 ` [kvm-devel] " Rusty Russell
[not found] ` <1176263593.26372.84.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2007-04-11 4:26 ` Avi Kivity
[not found] ` <461C6360.1060908-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-04-11 13:23 ` Rusty Russell
[not found] ` <1176297794.14322.72.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2007-04-11 14:28 ` Avi Kivity
[not found] ` <461CF098.3090003-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-04-11 23:30 ` Rusty Russell
[not found] ` <1176334200.14322.133.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2007-04-12 3:32 ` Avi Kivity
2007-04-16 0:22 ` [kvm-devel] " Rusty Russell
2007-04-16 5:13 ` Avi Kivity
[not found] ` <1175728768.12230.593.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2007-04-05 9:30 ` Ingo Molnar
[not found] ` <20070405093033.GC25448-X9Un+BFzKDI@public.gmane.org>
2007-04-05 9:58 ` Avi Kivity
2007-04-05 10:26 ` [kvm-devel] " Ingo Molnar
2007-04-05 11:26 ` Avi Kivity
[not found] ` <4614DCE1.70905-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-04-05 11:36 ` Ingo Molnar
2007-04-06 1:16 ` [kvm-devel] " Rusty Russell
2007-04-06 18:59 ` Ingo Molnar
2007-04-05 10:55 ` Ingo Molnar
2007-04-05 14:32 ` [kvm-devel] " Anthony Liguori
2007-04-06 10:37 ` Ingo Molnar
2007-04-06 11:07 ` Ingo Molnar
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