From: Rusty Russell <rusty@rustcorp.com.au>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: virtualization@lists.linux-foundation.org,
sjur.brandeland@stericsson.com
Subject: Re: [PATCH 3/6] virtio_ring: inline internal vring functions more aggressively.
Date: Thu, 07 Mar 2013 10:02:17 +1100 [thread overview]
Message-ID: <87ehfs9lom.fsf@rustcorp.com.au> (raw)
In-Reply-To: <20130306102412.GC16921@redhat.com>
"Michael S. Tsirkin" <mst@redhat.com> writes:
> On Wed, Mar 06, 2013 at 04:22:09PM +1100, Rusty Russell wrote:
>> We use inline and get gcc to do the right thing inlining the
>> "indirect" traversal functions. This also means we don't need to
>> clean the sgs.
>>
>> for i in `seq 50`; do /usr/bin/time -f 'Wall time:%e' ./vringh_test --indirect --eventidx --parallel --fast-vringh; done 2>&1 | stats --trim-outliers:
>>
>> Before:
>> Using CPUS 0 and 3
>> Guest: notified 0, pinged 39014-39063(39062)
>> Host: notified 39014-39063(39062), pinged 0
>> Wall time:1.900000-2.350000(1.921875)
>>
>> After:
>> Using CPUS 0 and 3
>> Guest: notified 0, pinged 39062-39063(39063)
>> Host: notified 39062-39063(39063), pinged 0
>> Wall time:1.760000-2.220000(1.789167)
>>
>> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
>
> It's pretty cool that gcc is able to optimize it like this.
> Which gcc version did you use here?
Gcc has done this for quite a while now... I reported a bug about it in
2008: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35728
This was i686-linux-gnu-gcc-4.7 (Ubuntu/Linaro 4.7.2-2ubuntu1) 4.7.2.
Cheers,
Rusty.
next prev parent reply other threads:[~2013-03-06 23:02 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-06 5:15 [PATCH 0/6] virtio_add_buf replacement Rusty Russell
2013-03-06 5:19 ` [PATCH 1/6] virtio_ring: virtqueue_add_sgs, to add multiple sgs Rusty Russell
2013-03-06 5:19 ` Rusty Russell
2013-03-06 5:20 ` [PATCH 2/6] virtio_ring: don't count elements twice for add_buf path Rusty Russell
2013-03-06 5:22 ` [PATCH 3/6] virtio_ring: inline internal vring functions more aggressively Rusty Russell
2013-03-06 10:24 ` Michael S. Tsirkin
2013-03-06 23:02 ` Rusty Russell [this message]
2013-03-06 5:23 ` [PATCH 4/6] virtio_ring: virtqueue_add_outbuf / virtqueue_add_inbuf Rusty Russell
2013-03-06 8:37 ` Asias He
2013-03-07 0:33 ` Rusty Russell
2013-03-07 8:15 ` Asias He
2013-03-06 5:24 ` [PATCH 5/6] tools/virtio: make vringh_test use inbuf/outbuf Rusty Russell
2013-03-06 5:24 ` [PATCH 6/6] virtio_scsi: use virtqueue_add_inbuf() for virtscsi_kick_event Rusty Russell
2013-03-06 8:09 ` [PATCH 0/6] virtio_add_buf replacement Asias He
2013-03-07 0:35 ` Rusty Russell
2013-03-07 8:22 ` Asias He
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