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Message-ID: <87bob7fyh9.fsf@rustcorp.com.au>
Date: Tue, 26 Feb 2013 15:44:26 +1030
From: Rusty Russell <rusty@...tcorp.com.au>
To: "Michael S. Tsirkin" <mst@...hat.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>, Asias He <asias@...hat.com>,
linux-kernel@...r.kernel.org,
virtualization@...ts.linux-foundation.org
Subject: Re: [PATCH 02/16] virtio_ring: virtqueue_add_sgs, to add multiple sgs.
"Michael S. Tsirkin" <mst@...hat.com> writes:
> On Tue, Feb 19, 2013 at 06:26:20PM +1030, Rusty Russell wrote:
>> virtio_scsi can really use this, to avoid the current hack of copying
>> the whole sg array. Some other things get slightly neater, too.
>>
>> Signed-off-by: Rusty Russell <rusty@...tcorp.com.au>
>
> Hmm, this makes add_buf a bit slower. virtio_test results
> (I'll send a patch to update the test shortly):
>
> Before:
> 0.09user 0.01system 0:00.12elapsed 91%CPU (0avgtext+0avgdata 480maxresident)k
> 0inputs+0outputs (0major+145minor)pagefaults 0swaps
>
> After:
> 0.11user 0.01system 0:00.13elapsed 90%CPU (0avgtext+0avgdata 480maxresident)k
> 0inputs+0outputs (0major+145minor)pagefaults 0swaps
Interesting: how much of this is due to the shim in virtqueue_add_buf()
to clean up the sg arrays?
(Perhaps we should make virtio_test run for longer, too).
BTW, you might be interested in:
https://github.com/rustyrussell/stats.git
Which provides a useful filter for multiple results.
Cheers,
Rusty.
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