From: Jason Wang <jasowang@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, virtualization@lists.linux-foundation.org
Subject: Re: [PATCH 2/6] vhost_net: use vhost_add_used_and_signal_n() in vhost_zerocopy_signal_used()
Date: Tue, 20 Aug 2013 10:33:08 +0800 [thread overview]
Message-ID: <5212D564.80200@redhat.com> (raw)
In-Reply-To: <20130816095426.GA21821@redhat.com>
On 08/16/2013 05:54 PM, Michael S. Tsirkin wrote:
> On Fri, Aug 16, 2013 at 01:16:26PM +0800, Jason Wang wrote:
>> > Switch to use vhost_add_used_and_signal_n() to avoid multiple calls to
>> > vhost_add_used_and_signal(). With the patch we will call at most 2 times
>> > (consider done_idx warp around) compared to N times w/o this patch.
>> >
>> > Signed-off-by: Jason Wang <jasowang@redhat.com>
> So? Does this help performance then?
>
Looks like it can especially when guest does support event index. When
guest enable tx interrupt, this can saves us some unnecessary signal to
guest. I will do some test.
WARNING: multiple messages have this Message-ID (diff)
From: Jason Wang <jasowang@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: kvm@vger.kernel.org, virtualization@lists.linux-foundation.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/6] vhost_net: use vhost_add_used_and_signal_n() in vhost_zerocopy_signal_used()
Date: Tue, 20 Aug 2013 10:33:08 +0800 [thread overview]
Message-ID: <5212D564.80200@redhat.com> (raw)
In-Reply-To: <20130816095426.GA21821@redhat.com>
On 08/16/2013 05:54 PM, Michael S. Tsirkin wrote:
> On Fri, Aug 16, 2013 at 01:16:26PM +0800, Jason Wang wrote:
>> > Switch to use vhost_add_used_and_signal_n() to avoid multiple calls to
>> > vhost_add_used_and_signal(). With the patch we will call at most 2 times
>> > (consider done_idx warp around) compared to N times w/o this patch.
>> >
>> > Signed-off-by: Jason Wang <jasowang@redhat.com>
> So? Does this help performance then?
>
Looks like it can especially when guest does support event index. When
guest enable tx interrupt, this can saves us some unnecessary signal to
guest. I will do some test.
next prev parent reply other threads:[~2013-08-20 2:33 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-16 5:16 [PATCH 0/6] vhost code cleanup and minor enhancement Jason Wang
2013-08-16 5:16 ` Jason Wang
2013-08-16 5:16 ` [PATCH 1/6] vhost_net: make vhost_zerocopy_signal_used() returns void Jason Wang
2013-08-16 5:16 ` Jason Wang
2013-08-16 5:16 ` [PATCH 2/6] vhost_net: use vhost_add_used_and_signal_n() in vhost_zerocopy_signal_used() Jason Wang
2013-08-16 5:16 ` Jason Wang
2013-08-16 9:54 ` Michael S. Tsirkin
2013-08-16 9:54 ` Michael S. Tsirkin
2013-08-20 2:33 ` Jason Wang [this message]
2013-08-20 2:33 ` Jason Wang
2013-08-23 8:50 ` Jason Wang
2013-08-23 8:50 ` Jason Wang
2013-08-25 11:48 ` Michael S. Tsirkin
2013-08-25 11:48 ` Michael S. Tsirkin
2013-08-16 5:16 ` [PATCH 3/6] vhost: switch to use vhost_add_used_n() Jason Wang
2013-08-16 5:16 ` Jason Wang
2013-08-16 9:56 ` Michael S. Tsirkin
2013-08-16 9:56 ` Michael S. Tsirkin
2013-08-20 2:36 ` Jason Wang
2013-08-20 2:36 ` Jason Wang
2013-08-16 5:16 ` [PATCH 4/6] vhost_net: determine whether or not to use zerocopy at one time Jason Wang
2013-08-16 5:16 ` Jason Wang
2013-08-16 5:16 ` [PATCH 5/6] vhost_net: poll vhost queue after marking DMA is done Jason Wang
2013-08-16 5:16 ` Jason Wang
2013-08-16 10:00 ` Michael S. Tsirkin
2013-08-16 10:00 ` Michael S. Tsirkin
2013-08-20 2:44 ` Jason Wang
2013-08-20 2:44 ` Jason Wang
2013-08-16 5:16 ` [PATCH 6/6] vhost_net: remove the max pending check Jason Wang
2013-08-16 5:16 ` Jason Wang
2013-08-16 10:02 ` Michael S. Tsirkin
2013-08-16 10:02 ` Michael S. Tsirkin
2013-08-20 2:48 ` Jason Wang
2013-08-20 2:48 ` Jason Wang
2013-08-23 8:55 ` Jason Wang
2013-08-23 8:55 ` Jason Wang
2013-08-25 11:53 ` Michael S. Tsirkin
2013-08-25 11:53 ` Michael S. Tsirkin
2013-08-26 7:00 ` Jason Wang
2013-08-26 7:00 ` Jason Wang
2013-08-30 3:23 ` Jason Wang
2013-08-30 3:23 ` Jason Wang
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