From: Andi Kleen <andi@firstfloor.org>
To: Alok Kataria <akataria@vmware.com>
Cc: Andi Kleen <andi@firstfloor.org>, Ingo Molnar <mingo@elte.hu>,
"H. Peter Anvin" <hpa@zytor.com>,
LKML <linux-kernel@vger.kernel.org>,
the arch/x86 maintainers <x86@kernel.org>,
Daniel Hecht <dhecht@vmware.com>
Subject: Re: [PATCH] Skip tsc synchronization checks if CONSTANT_TSC bit is set.
Date: Thu, 23 Oct 2008 00:54:09 +0200 [thread overview]
Message-ID: <20081022225409.GB27492@one.firstfloor.org> (raw)
In-Reply-To: <1224713518.13953.46.camel@alok-dev1>
> Not really, there are problems with the pm timer too, the one about
> missing the counter wrap and time dropping in chunks of 4 seconds.
> Tried to explain it over here, http://lkml.org/lkml/2008/10/22/525
Well then pit. Or are you saying time is always broken on VMware & Linux?
> So TSC is the ideal clocksource from performance and correctness point
> of view for VMware.
But you don't seem to emulate it "ideal"ly otherwise you wouldn't
need all these hacks you're adding?
I think you should either implement a TSC that matches what
real hardware does (including CPUID semantics) or implement
a real vmware PV timer and just say it's PV and not fully virtualized.
But doesn't the vmware paravirt ops have that already anyways?
But I personally think it wouldn't really scale to add detection for
more and more "nearly PV" hypervisors to the standard native kernel.
-Andi
next prev parent reply other threads:[~2008-10-22 22:46 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-21 1:35 [PATCH 0/3] Improve TSC as a clocksource under VMware Alok Kataria
2008-10-21 5:55 ` Chris Snook
2008-10-21 19:11 ` Alok Kataria
2008-10-22 19:26 ` Alok Kataria
2008-10-22 19:29 ` Jeff Hansen
2008-10-21 9:43 ` Andi Kleen
2008-10-21 16:41 ` Alok Kataria
2008-10-21 17:40 ` Andi Kleen
2008-10-21 18:04 ` Alok Kataria
2008-10-21 18:15 ` Andi Kleen
2008-10-21 19:10 ` Alok Kataria
2008-10-21 19:27 ` Andi Kleen
2008-10-21 19:47 ` Alok Kataria
2008-10-21 21:41 ` Alok Kataria
2008-10-22 19:23 ` [PATCH] Skip tsc synchronization checks if CONSTANT_TSC bit is set Alok Kataria
2008-10-22 19:26 ` Ingo Molnar
2008-10-22 19:30 ` Alok Kataria
2008-10-22 20:17 ` Andi Kleen
2008-10-22 22:04 ` Alok Kataria
2008-10-22 19:58 ` Andi Kleen
2008-10-22 22:00 ` Alok Kataria
2008-10-22 22:13 ` Andi Kleen
2008-10-22 22:11 ` Alok Kataria
2008-10-22 22:54 ` Andi Kleen [this message]
2008-10-23 2:21 ` Alok Kataria
2008-10-23 8:10 ` Andi Kleen
2008-10-23 23:39 ` Alok Kataria
2008-10-23 23:47 ` H. Peter Anvin
2008-10-24 0:25 ` Andi Kleen
2008-10-24 0:46 ` H. Peter Anvin
2008-10-24 7:23 ` Andi Kleen
2008-10-24 15:30 ` H. Peter Anvin
2008-10-24 19:25 ` Andi Kleen
2008-10-24 19:19 ` H. Peter Anvin
2008-10-24 19:34 ` Andi Kleen
2008-10-24 19:50 ` Alok Kataria
2008-10-24 20:18 ` Dan Hecht
2008-10-24 1:12 ` Alok Kataria
2008-10-24 1:18 ` H. Peter Anvin
2008-10-22 22:15 ` Alan Cox
2008-10-22 22:17 ` Alok Kataria
2008-10-21 9:50 ` [PATCH 0/3] Improve TSC as a clocksource under VMware Pavel Machek
2008-10-21 16:48 ` Alok Kataria
2008-10-21 18:36 ` Pavel Machek
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