All of lore.kernel.org
 help / color / mirror / Atom feed
From: Alex Bligh <alex@alex.org.uk>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Hans de Goede <hdegoede@redhat.com>,
	qemu-devel@nongnu.org, Alex Bligh <alex@alex.org.uk>
Subject: Re: [Qemu-devel] [PATCH] main-loop: Don't lock starve io-threads when main_loop_tlg has pending events
Date: Wed, 9 Oct 2013 17:19:06 +0100	[thread overview]
Message-ID: <65410BFC-E64A-47FD-AC5C-6B70F69E1D06@alex.org.uk> (raw)
In-Reply-To: <52556A35.7060300@redhat.com>


On 9 Oct 2013, at 15:37, Paolo Bonzini wrote:

> 
> I agree.  Do you also agree that the equivalent workaround, before
> Alex's patch, was MIN_REARM_TIMER_NS (and thus 250 microseconds)?

I don't think this was the case, as if it's a timer constantly
expiring we'd have seen select() exit as soon as it was entered
by the fd poked by the signal. That might be far more frequent.
I think the equivalent would be something like: if the 'zero'
timeout comes from the deadline calculation (and not
nonblocking=true) then release the lock anyway. I think
that would be a reasonable approach.

I would however like to get to the bottom of what's causing
this as even pre my changes playing sound was apparently taking
50% CPU, which is not good. I am completely packed until the
weekend but I propose producing a timer debug patch which
will instrument what is expiring constantly (unless the
problem with spice is obvious to someone).

-- 
Alex Bligh

  reply	other threads:[~2013-10-09 16:19 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-08 19:10 [Qemu-devel] [PATCH] main-loop: Don't lock starve io-threads when main_loop_tlg has pending events Hans de Goede
2013-10-08 19:13 ` Paolo Bonzini
2013-10-08 19:21   ` Hans de Goede
2013-10-08 19:33     ` Alex Bligh
2013-10-08 19:41       ` Hans de Goede
2013-10-08 20:01         ` Alex Bligh
2013-10-08 20:07           ` Alex Bligh
2013-10-08 20:16           ` Hans de Goede
2013-10-08 20:32             ` Alex Bligh
2013-10-08 20:50             ` Paolo Bonzini
2013-10-09 12:58               ` Hans de Goede
2013-10-09 13:18                 ` Alex Bligh
2013-10-09 18:03                   ` Hans de Goede
2013-10-09 18:15                     ` Hans de Goede
2013-10-09 18:28                     ` Alex Bligh
2013-10-09 18:36                       ` Alex Bligh
2013-10-09 18:49                         ` Hans de Goede
2013-10-09 19:03                           ` Paolo Bonzini
2013-10-09 19:15                             ` Hans de Goede
2013-10-09 14:37                 ` Paolo Bonzini
2013-10-09 16:19                   ` Alex Bligh [this message]
2013-10-09 16:26                     ` Paolo Bonzini
2013-10-09 16:33                       ` Alex Bligh
2013-10-09 17:53                       ` Hans de Goede
2013-10-09 18:09                   ` Hans de Goede
2013-10-08 19:48 ` Alex Bligh
2013-10-08 20:01   ` Hans de Goede
2013-10-08 21:25     ` Alex Bligh

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=65410BFC-E64A-47FD-AC5C-6B70F69E1D06@alex.org.uk \
    --to=alex@alex.org.uk \
    --cc=hdegoede@redhat.com \
    --cc=pbonzini@redhat.com \
    --cc=qemu-devel@nongnu.org \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.