From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Cc: "Chris Webb" <chris@arachsys.com>,
Jernej@gnu.org, "Avi Kivity" <avi@redhat.com>,
kvm@vger.kernel.org, Simončič <jernej's-kvm@eternallybored.org>
Subject: Re: [Qemu-devel] High CPU use of -usbdevice tablet (was Re: KVM usability)
Date: Sun, 4 Apr 2010 22:03:05 +0100 [thread overview]
Message-ID: <201004042203.06119.paul@codesourcery.com> (raw)
In-Reply-To: <4BB8C51A.6070908@redhat.com>
> > The USB HID devices implement the SET_IDLE command, so the polling
> > interval will have no real effect on performance.
>
> On a Linux guest (F12), I see 125 USB interrupts per second with no
> mouse movement, so something is broken (on the guest or host).
Turns out to be a a bug in the UHCI emulation. It should only raise an
interrupt if the transfer actually completes (i.e. the active bit is set to
zero). Fixed by 5bd2c0d7.
I was testing with an OHCI controller, which does not have this bug.
Paul
next prev parent reply other threads:[~2010-04-04 21:03 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1267068445.1726.25.camel@localhost>
[not found] ` <1267089644.12790.74.camel@laptop>
[not found] ` <1267152599.1726.76.camel@localhost>
[not found] ` <20100226090147.GH15885@elte.hu>
[not found] ` <4B879A2F.50203@redhat.com>
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[not found] ` <4B87A6BF.3090301@redhat.com>
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[not found] ` <4B8813F2.8090208@redhat.com>
[not found] ` <20100227105643.GA17425@elte.hu>
2010-02-27 13:30 ` [Qemu-devel] Re: KVM usability Jan Kiszka
[not found] ` <d9c105ea1003011312s935c3c5haa1ec80aebe14d88@mail.gmail.com>
[not found] ` <4B8C38B8.8010007@codemonkey.ws>
[not found] ` <1267498953.2460.32.camel@x200>
[not found] ` <20100302082118.GT1924@arachsys.com>
[not found] ` <428008581.20100302103400@eternallybored.org>
[not found] ` <4B938F9D.7010207@redhat.com>
2010-04-04 12:31 ` [Qemu-devel] High CPU use of -usbdevice tablet (was Re: KVM usability) Chris Webb
2010-04-04 14:25 ` Paul Brook
2010-04-04 16:58 ` Avi Kivity
2010-04-04 21:03 ` Paul Brook [this message]
2010-04-04 21:53 ` Paul Brook
2010-04-05 8:22 ` Avi Kivity
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