From: Andi Kleen <andi@firstfloor.org>
To: Alexander Graf <agraf@suse.de>
Cc: Andi Kleen <andi@firstfloor.org>,
"David S. Ahern" <daahern@cisco.com>,
kvm-devel <kvm@vger.kernel.org>,
Marcelo Tosatti <mtosatti@redhat.com>,
Glauber de Oliveira Costa <gcosta@redhat.com>,
Avi Kivity <avi@redhat.com>
Subject: Re: gettimeofday "slow" in RHEL4 guests
Date: Tue, 25 Nov 2008 13:52:59 +0100 [thread overview]
Message-ID: <20081125125259.GH6703@one.firstfloor.org> (raw)
In-Reply-To: <CC19AD88-0576-47B2-AC76-A51F317964BD@suse.de>
> But yeah - the remapping of HPET timers to virtual HPET timers sounds
> pretty tough. I wonder if one could overcome that with a little
> hardware support though ...
For gettimeofday better make TSC work. Even in the best case (no
virtualization) it is much faster than HPET because it sits in the CPU,
while HPET is far away on the external south bridge.
For other HPET usages (interval timer etc.) which are less
performance critical I suppose vmexits are
not a serious problem so a standard software device model should work.
-Andi
next prev parent reply other threads:[~2008-11-25 12:42 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-24 17:47 gettimeofday "slow" in RHEL4 guests David S. Ahern
2008-11-25 4:41 ` David S. Ahern
2008-11-25 10:14 ` Andi Kleen
2008-11-25 11:17 ` Alexander Graf
2008-11-25 11:48 ` Andi Kleen
2008-11-25 12:13 ` Alexander Graf
2008-11-25 12:52 ` Andi Kleen [this message]
2008-12-28 18:38 ` Marcelo Tosatti
2008-12-29 12:37 ` Yang, Sheng
2008-12-29 13:11 ` Avi Kivity
2008-12-29 16:12 ` Dor Laor
2008-12-29 16:27 ` Avi Kivity
2008-12-29 16:29 ` Avi Kivity
2008-11-25 17:20 ` Hollis Blanchard
2008-11-25 19:09 ` David S. Ahern
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