From: "David S. Ahern" <daahern@cisco.com>
To: Michael Tokarev <mjt@tls.msk.ru>
Cc: Avi Kivity <avi@redhat.com>, KVM list <kvm@vger.kernel.org>
Subject: Re: high load with usb device
Date: Tue, 14 Sep 2010 10:09:18 -0600 [thread overview]
Message-ID: <4C8F9E2E.5060003@cisco.com> (raw)
In-Reply-To: <4C8F9C14.9070509@msgid.tls.msk.ru>
On 09/14/10 10:00, Michael Tokarev wrote:
> 14.09.2010 19:51, David S. Ahern пишет:
>> cat /sys/devices/system/clocksource/clocksource0/current_clocksource
>
> It's tsc (AthlonII CPU). Also available are hpet and acpi_pm.
> Switching to hpet or acpi_pm does not have visible effect, at
> least not while the guest is running.
acpi_pm takes more cycles to read. On my laptop switching from hpet to
acpi_pm caused the winxp VM to jump up in CPU usage. For both time
sources 'perf top -p <pid of main thread>' shows timer reads as the top
function for qemu-kvm (e.g., read_hpet).
On a Nehalem box the clock source is TSC. 'perf top -p <pid>' for a
winxp VM does not show clock reads at all.
David
>
> Thanks!
>
> /mjt
next prev parent reply other threads:[~2010-09-14 16:09 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-03 12:21 high load with win7 & usb tablet Michael Tokarev
2010-09-10 11:47 ` Jes Sorensen
2010-09-10 12:16 ` Michael Tokarev
2010-09-10 16:17 ` high load with usb device Michael Tokarev
2010-09-12 9:26 ` Avi Kivity
2010-09-14 6:51 ` Michael Tokarev
2010-09-14 9:06 ` Avi Kivity
2010-09-14 9:08 ` Avi Kivity
2010-09-14 10:00 ` Michael Tokarev
2010-09-14 10:07 ` Avi Kivity
2010-09-14 10:25 ` Michael Tokarev
2010-09-14 10:39 ` Avi Kivity
2010-09-14 11:02 ` Michael Tokarev
2010-09-14 13:15 ` Michael Tokarev
2010-09-14 13:25 ` Avi Kivity
2010-09-14 13:29 ` Michael Tokarev
2010-09-14 13:38 ` Michael Tokarev
2010-09-14 14:45 ` Avi Kivity
2010-09-14 14:53 ` Michael Tokarev
2010-09-14 16:00 ` Avi Kivity
2010-09-14 16:29 ` Michael Tokarev
2010-09-14 16:37 ` Avi Kivity
2010-09-14 16:50 ` Michael Tokarev
2010-09-14 16:45 ` David S. Ahern
2010-09-14 15:51 ` David S. Ahern
2010-09-14 16:00 ` Michael Tokarev
2010-09-14 16:09 ` David S. Ahern [this message]
2010-09-10 12:19 ` high load with win7 & usb tablet Avi Kivity
2010-09-10 12:44 ` Michael Tokarev
2010-09-10 12:50 ` Avi Kivity
[not found] ` <4C8A44E6.2060008@msgid.tls.msk.ru>
2010-09-10 14:56 ` Avi Kivity
2010-09-10 15:03 ` Michael Tokarev
2010-09-10 16:03 ` Avi Kivity
2010-09-14 8:26 ` Brad Campbell
2010-09-14 8:33 ` Michael Tokarev
2010-09-14 8:46 ` Brad Campbell
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