linux-kernel - Re: [PATCH 2/6] vhost_net: use vhost_add_used_and_signal_n() in vhost_zerocopy_signal

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <5212D564.80200@redhat.com>
Date:	Tue, 20 Aug 2013 10:33:08 +0800
From:	Jason Wang <jasowang@...hat.com>
To:	"Michael S. Tsirkin" <mst@...hat.com>
CC:	kvm@...r.kernel.org, virtualization@...ts.linux-foundation.org,
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/6] vhost_net: use vhost_add_used_and_signal_n() in vhost_zerocopy_signal_used()

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@...hat.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.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/