From: Avi Kivity <avi@redhat.com>
To: Gregory Haskins <ghaskins@novell.com>
Cc: linux-kernel@vger.kernel.org, agraf@suse.de,
pmullaney@novell.com, pmorreale@novell.com,
anthony@codemonkey.ws, rusty@rustcorp.com.au,
netdev@vger.kernel.org, kvm@vger.kernel.org
Subject: Re: [RFC PATCH 01/17] shm-signal: shared-memory signals
Date: Wed, 01 Apr 2009 15:24:50 +0300 [thread overview]
Message-ID: <49D35D12.6080209@redhat.com> (raw)
In-Reply-To: <49D35A2B.10907@novell.com>
Gregory Haskins wrote:
> Note that this is exactly what I do (though it is device specific).
> venet-tap has a ioq_notifier registered on its "rx" ring (which is the
> tx-ring for the guest) that simply calls ioq_notify_disable() (which
> calls shm_signal_disable() under the covers) and it wakes its
> rx-thread. This all happens in the context of the hypercall, which then
> returns and allows the vcpu to re-enter guest mode immediately.
>
I think this is suboptimal. The ring is likely to be cache hot on the
current cpu, waking a thread will introduce scheduling latency + IPI
+cache-to-cache transfers.
On a benchmark setup, host resources are likely to exceed guest
requirements, so you can throw cpu at the problem and no one notices.
But I think the bits/cycle figure will decrease, even if bits/sec increases.
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
next prev parent reply other threads:[~2009-04-01 12:24 UTC|newest]
Thread overview: 150+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-31 18:42 [RFC PATCH 00/17] virtual-bus Gregory Haskins
2009-03-31 18:42 ` [RFC PATCH 01/17] shm-signal: shared-memory signals Gregory Haskins
2009-03-31 20:44 ` Avi Kivity
2009-03-31 20:58 ` Gregory Haskins
2009-03-31 21:05 ` Avi Kivity
2009-04-01 12:12 ` Gregory Haskins
2009-04-01 12:24 ` Avi Kivity [this message]
2009-04-01 13:57 ` Gregory Haskins
2009-03-31 18:42 ` [RFC PATCH 02/17] vbus: add virtual-bus definitions Gregory Haskins
2009-04-02 16:06 ` Ben Hutchings
2009-04-02 18:13 ` Gregory Haskins
2009-03-31 18:43 ` [RFC PATCH 03/17] vbus: add connection-client helper infrastructure Gregory Haskins
2009-03-31 18:43 ` [RFC PATCH 04/17] vbus: add bus-registration notifiers Gregory Haskins
2009-03-31 18:43 ` [RFC PATCH 05/17] vbus: add a "vbus-proxy" bus model for vbus_driver objects Gregory Haskins
2009-03-31 18:43 ` [RFC PATCH 06/17] ioq: Add basic definitions for a shared-memory, lockless queue Gregory Haskins
2009-03-31 18:43 ` [RFC PATCH 07/17] ioq: add vbus helpers Gregory Haskins
2009-03-31 18:43 ` [RFC PATCH 08/17] venet: add the ABI definitions for an 802.x packet interface Gregory Haskins
2009-03-31 18:43 ` [RFC PATCH 09/17] net: Add vbus_enet driver Gregory Haskins
2009-03-31 20:39 ` Stephen Hemminger
2009-04-02 11:43 ` Gregory Haskins
2009-03-31 18:43 ` [RFC PATCH 10/17] venet-tap: Adds a "venet" compatible "tap" device to VBUS Gregory Haskins
2009-03-31 18:43 ` [RFC PATCH 11/17] venet: add scatter-gather support Gregory Haskins
2009-03-31 18:43 ` [RFC PATCH 12/17] venettap: " Gregory Haskins
2009-03-31 18:43 ` [RFC PATCH 13/17] x86: allow the irq->vector translation to be determined outside of ioapic Gregory Haskins
2009-03-31 19:16 ` Alan Cox
2009-03-31 20:02 ` Gregory Haskins
2009-03-31 18:44 ` [RFC PATCH 14/17] kvm: add a reset capability Gregory Haskins
2009-03-31 19:22 ` Avi Kivity
2009-03-31 20:02 ` Gregory Haskins
2009-03-31 20:18 ` Avi Kivity
2009-03-31 20:37 ` Gregory Haskins
2009-03-31 18:44 ` [RFC PATCH 15/17] kvm: add dynamic IRQ support Gregory Haskins
2009-03-31 19:20 ` Avi Kivity
2009-03-31 19:39 ` Gregory Haskins
2009-03-31 20:13 ` Avi Kivity
2009-03-31 20:32 ` Gregory Haskins
2009-03-31 20:59 ` Avi Kivity
2009-03-31 18:44 ` [RFC PATCH 16/17] kvm: Add VBUS support to the host Gregory Haskins
2009-03-31 18:44 ` [RFC PATCH 17/17] kvm: Add guest-side support for VBUS Gregory Haskins
2009-03-31 20:18 ` [RFC PATCH 00/17] virtual-bus Andi Kleen
2009-04-01 12:03 ` Gregory Haskins
2009-04-01 13:23 ` Andi Kleen
2009-04-01 14:19 ` Gregory Haskins
2009-04-01 14:42 ` Gregory Haskins
2009-04-01 17:01 ` Andi Kleen
2009-04-01 18:45 ` Anthony Liguori
2009-04-01 20:40 ` Chris Wright
2009-04-01 21:11 ` Gregory Haskins
2009-04-01 21:28 ` Chris Wright
2009-04-01 22:10 ` Gregory Haskins
2009-04-02 6:00 ` Chris Wright
2009-04-02 3:11 ` Herbert Xu
2009-04-01 21:09 ` Gregory Haskins
2009-04-02 0:29 ` Anthony Liguori
2009-04-02 3:11 ` Gregory Haskins
2009-04-02 6:51 ` Avi Kivity
2009-04-02 8:52 ` Herbert Xu
2009-04-02 9:02 ` Avi Kivity
2009-04-02 9:16 ` Herbert Xu
2009-04-02 9:27 ` Avi Kivity
2009-04-02 9:29 ` Herbert Xu
2009-04-02 9:33 ` Herbert Xu
2009-04-02 9:38 ` Avi Kivity
2009-04-02 9:41 ` Herbert Xu
2009-04-02 9:43 ` Avi Kivity
2009-04-02 9:44 ` Herbert Xu
2009-04-02 11:06 ` Gregory Haskins
2009-04-02 11:59 ` Avi Kivity
2009-04-02 12:30 ` Gregory Haskins
2009-04-02 12:43 ` Avi Kivity
2009-04-02 13:03 ` Gregory Haskins
2009-04-02 12:13 ` Rusty Russell
2009-04-02 12:50 ` Gregory Haskins
2009-04-02 12:52 ` Gregory Haskins
2009-04-02 13:07 ` Avi Kivity
2009-04-02 13:22 ` Gregory Haskins
2009-04-02 13:27 ` Avi Kivity
2009-04-02 14:05 ` Gregory Haskins
2009-04-02 14:50 ` Herbert Xu
2009-04-02 15:00 ` Avi Kivity
2009-04-02 15:40 ` Herbert Xu
2009-04-02 15:57 ` Avi Kivity
2009-04-02 16:09 ` Herbert Xu
2009-04-02 16:54 ` Avi Kivity
2009-04-02 17:06 ` Herbert Xu
2009-04-02 17:17 ` Herbert Xu
2009-04-03 12:25 ` Avi Kivity
2009-04-02 15:10 ` Michael S. Tsirkin
2009-04-03 4:43 ` Jeremy Fitzhardinge
2009-04-02 10:55 ` Gregory Haskins
2009-04-02 11:48 ` Avi Kivity
2009-04-03 10:58 ` Gerd Hoffmann
2009-04-03 11:03 ` Avi Kivity
2009-04-03 11:12 ` Herbert Xu
2009-04-03 11:46 ` Avi Kivity
2009-04-03 11:48 ` Herbert Xu
2009-04-03 11:54 ` Avi Kivity
2009-04-03 11:55 ` Herbert Xu
2009-04-03 12:02 ` Avi Kivity
2009-04-03 13:05 ` Herbert Xu
2009-04-03 11:18 ` Andi Kleen
2009-04-03 11:34 ` Herbert Xu
2009-04-03 11:46 ` Avi Kivity
2009-04-03 11:28 ` Gregory Haskins
2009-04-02 10:46 ` Gregory Haskins
2009-04-02 11:43 ` Avi Kivity
2009-04-02 12:22 ` Gregory Haskins
2009-04-02 12:42 ` Avi Kivity
2009-04-02 12:54 ` Gregory Haskins
2009-04-02 13:08 ` Avi Kivity
2009-04-02 13:36 ` Gregory Haskins
2009-04-02 13:45 ` Avi Kivity
2009-04-02 14:24 ` Gregory Haskins
2009-04-02 14:32 ` Avi Kivity
2009-04-02 14:41 ` Avi Kivity
2009-04-02 14:49 ` Anthony Liguori
2009-04-02 16:09 ` Anthony Liguori
2009-04-02 16:19 ` Avi Kivity
2009-04-02 18:18 ` Anthony Liguori
2009-04-03 1:11 ` Herbert Xu
2009-04-20 18:02 ` [kvm] " Alex Williamson
2009-04-20 18:02 ` Alex Williamson
2009-04-03 12:03 ` Gregory Haskins
2009-04-03 12:15 ` Avi Kivity
2009-04-03 13:13 ` Gregory Haskins
2009-04-03 13:37 ` Avi Kivity
2009-04-03 13:37 ` Avi Kivity
2009-04-03 16:28 ` Gregory Haskins
2009-04-03 16:28 ` Gregory Haskins
2009-04-05 10:00 ` Avi Kivity
2009-04-05 10:00 ` Avi Kivity
2009-04-02 3:09 ` Herbert Xu
2009-04-02 6:46 ` Avi Kivity
2009-04-02 8:54 ` Herbert Xu
2009-04-02 9:03 ` Avi Kivity
2009-04-02 9:05 ` Herbert Xu
2009-04-01 20:29 ` Gregory Haskins
2009-04-01 22:23 ` Andi Kleen
2009-04-01 23:05 ` Gregory Haskins
2009-04-01 6:08 ` Rusty Russell
2009-04-01 11:35 ` Gregory Haskins
2009-04-02 1:24 ` Rusty Russell
2009-04-02 2:27 ` Gregory Haskins
2009-04-01 16:10 ` Anthony Liguori
2009-04-05 3:44 ` Rusty Russell
2009-04-05 8:06 ` Avi Kivity
2009-04-05 14:13 ` Anthony Liguori
2009-04-05 16:10 ` Avi Kivity
2009-04-05 16:45 ` Anthony Liguori
2009-04-02 3:15 ` Herbert Xu
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