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From: Paolo Bonzini <pbonzini@redhat.com>
To: Paul Brook <paul@codesourcery.com>
Cc: avi@redhat.com, xen-devel@lists.xensource.com,
	qemu-devel@nongnu.org,
	Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Subject: Re: [Qemu-devel] [PATCH v3 6/6] qemu_calculate_timeout: increase minimum timeout to 1h
Date: Fri, 10 Feb 2012 09:03:42 +0100	[thread overview]
Message-ID: <4F34CF5E.9080106@redhat.com> (raw)
In-Reply-To: <201202100026.40727.paul@codesourcery.com>

On 02/10/2012 01:26 AM, Paul Brook wrote:
> The reason we have this is because there are bits of code that rely on
> polling.  IIRC slirp and the floppy DMA engine were the main culprits.
> qemu_calculate_timeout is an ugly hack to poll at least once a second,
> allowing the guest to make forward progress when we miss an event.

At least the floppy DMA engine is fine with it, it uses idle bottom 
halves (which are a hack and could be replaced by timers, but that's not 
relevant now).

Slirp's timeouts indeed require polling.

                 if (time_fasttimo && ((curtime - time_fasttimo) >= 2)) {
                         tcp_fasttimo(slirp);
                         time_fasttimo = 0;
                 }
                 if (do_slowtimo && ((curtime - last_slowtimo) >= 499)) {
                         ip_slowtimo(slirp);
                         tcp_slowtimo(slirp);
                         last_slowtimo = curtime;
                 }

Paolo

  reply	other threads:[~2012-02-10  8:04 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-27 18:20 [Qemu-devel] [PATCH v3 0/6] prevent Qemu from waking up needlessly Stefano Stabellini
2012-01-27 18:21 ` [Qemu-devel] [PATCH v3 1/6] xen: do not initialize the interval timer emulator Stefano Stabellini
2012-01-27 19:09   ` Jan Kiszka
2012-01-30 11:39     ` Stefano Stabellini
2012-01-30 15:13       ` Jan Kiszka
2012-01-27 18:21 ` [Qemu-devel] [PATCH v3 2/6] xen: disable rtc_clock Stefano Stabellini
2012-01-27 20:08   ` Paolo Bonzini
2012-01-30 11:58     ` Stefano Stabellini
2012-01-27 18:21 ` [Qemu-devel] [PATCH v3 3/6] xen: introduce an event channel for buffered io event notifications Stefano Stabellini
2012-01-27 18:21 ` [Qemu-devel] [PATCH v3 4/6] timers: the rearm function should be able to handle delta = INT64_MAX Stefano Stabellini
2012-01-27 18:21 ` [Qemu-devel] [PATCH v3 5/6] qemu_next_alarm_deadline: check the expire time of a clock only if it is enabled Stefano Stabellini
2012-01-27 18:21 ` [Qemu-devel] [PATCH v3 6/6] qemu_calculate_timeout: increase minimum timeout to 1h Stefano Stabellini
2012-02-10  0:26   ` Paul Brook
2012-02-10  8:03     ` Paolo Bonzini [this message]
2012-02-10  9:52       ` Paul Brook
2012-02-10 10:45         ` Paolo Bonzini
2012-02-10 11:09           ` Paul Brook
2012-02-10 11:19             ` Stefano Stabellini
2012-02-10 11:18               ` Paolo Bonzini
2012-02-10 11:32                 ` Jan Kiszka
2012-02-10 17:07                   ` Stefano Stabellini
2012-02-10 23:34                     ` Paul Brook
2012-02-13 11:52                       ` Stefano Stabellini
2012-02-14 10:52                         ` Paul Brook
2012-02-14 11:55                           ` Stefano Stabellini

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