From: Pekka Enberg <penberg@kernel.org>
To: Asias He <asias.hejun@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>, Ingo Molnar <mingo@elte.hu>,
Sasha Levin <levinsasha928@gmail.com>,
Prasad Joshi <prasadjoshi124@gmail.com>,
kvm@vger.kernel.org
Subject: Re: [PATCH v2 4/4] kvm tools: Fix virtio console hangs by removing IRQ injection for tx path
Date: Sun, 08 May 2011 20:05:29 +0300 [thread overview]
Message-ID: <1304874329.10621.45.camel@jaguar> (raw)
In-Reply-To: <1304860165-28810-5-git-send-email-asias.hejun@gmail.com>
On Sun, 2011-05-08 at 21:09 +0800, Asias He wrote:
> As virtio spec says:
>
> """
> Because this is high importance and low bandwidth, the current Linux
> implementation polls for the buffer to be used, rather than waiting
> for an interrupt, simplifying the implementation signicantly.
> """
>
> drivers/char/virtio_console.c
> send_buf() {
> ...
> /* Tell Host to go! */
> virtqueue_kick(out_vq);
> ...
> while (!virtqueue_get_buf(out_vq, &len))
> cpu_relax();
> ...
> }
>
> The console hangs can simply be reproduced by yes command which
> gives tremendous console IOs and IRQs.
Sasha, does this fix the hangs you were seeing? We should re-enable
virtio console unconditionally if this does - that increases test
coverage for virtio console.
Pekka
next prev parent reply other threads:[~2011-05-08 17:05 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-08 13:09 [PATCH v2 0/4] Resend this patch series Asias He
2011-05-08 13:09 ` [PATCH v2 1/4] kvm tools: Use virt_queue__trigger_irq() to trigger IRQ for virtio console Asias He
2011-05-08 13:09 ` [PATCH v2 2/4] kvm tools: Use virt_queue__trigger_irq() to trigger IRQ for virtio blk Asias He
2011-05-08 13:09 ` [PATCH v2 3/4] kvm tools: Use virt_queue__trigger_irq() to trigger IRQ for virtio rng Asias He
2011-05-08 13:09 ` [PATCH v2 4/4] kvm tools: Fix virtio console hangs by removing IRQ injection for tx path Asias He
2011-05-08 17:05 ` Pekka Enberg [this message]
2011-05-08 17:21 ` Sasha Levin
2011-05-08 17:28 ` Pekka Enberg
2011-05-08 17:29 ` Sasha Levin
2011-05-08 17:34 ` Pekka Enberg
2011-05-08 17:35 ` Sasha Levin
2011-05-08 17:41 ` Pekka Enberg
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1304874329.10621.45.camel@jaguar \
--to=penberg@kernel.org \
--cc=asias.hejun@gmail.com \
--cc=gorcunov@gmail.com \
--cc=kvm@vger.kernel.org \
--cc=levinsasha928@gmail.com \
--cc=mingo@elte.hu \
--cc=prasadjoshi124@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox