From: Ingo Molnar <mingo@elte.hu>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
Andrew Morton <akpm@linux-foundation.org>,
the arch/x86 maintainers <x86@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Xen-devel <xen-devel@lists.xensource.com>
Subject: Re: [PATCH] xen: core dom0 support
Date: Tue, 10 Mar 2009 13:44:00 +0100 [thread overview]
Message-ID: <20090310124400.GG5794@elte.hu> (raw)
In-Reply-To: <49B55AB0.1070605@goop.org>
* Jeremy Fitzhardinge <jeremy@goop.org> wrote:
>> Yeah - it was Jeremy expressed doubt in the numbers, not me.
>
> Mainly because I was seeing the instruction and cycle counts
> completely unchanged from run to run, which is implausible.
> They're not zero, so they're clearly measurements of
> *something*, but not cycles and instructions, since we know
> that they're changing. So what are they measurements of? And
> if they're not what they claim, are the other numbers more
> meaningful?
cycle count not changing in a macro-workload is not plausible.
Instruction count not changing can happen sometimes - if the
workload is deterministic (which this one is) and we happen to
get exactly the same number of timer irqs during the test. But
it's more common that it varies slightly - especially on SMP
where task balancing can be timing-dependent and hence is noise.
Ingo
next prev parent reply other threads:[~2009-03-10 12:44 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-28 1:59 Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen dom0: Make hvc_xen console work for dom0 Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen dom0: Initialize xenbus " Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen dom0: Set up basic IO permissions " Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen-dom0: only selectively disable cpu features Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen dom0: Add support for the platform_ops hypercall Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen mtrr: Add mtrr_ops support for Xen mtrr Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen: disable PAT Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen/dom0: use _PAGE_IOMAP in ioremap to do machine mappings Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] paravirt/xen: add pvop for page_is_ram Jeremy Fitzhardinge
2009-03-10 1:07 ` H. Peter Anvin
2009-03-10 21:19 ` Jeremy Fitzhardinge
2009-03-10 22:21 ` H. Peter Anvin
2009-03-10 22:44 ` Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen/dom0: Use host E820 map Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen: implement XENMEM_machphys_mapping Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen: clear reserved bits in l3 entries given in the initial pagetables Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen/dom0: add XEN_DOM0 config option Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen: allow enable use of VGA console on dom0 Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen mtrr: Use specific cpu_has_foo macros instead of generic cpu_has() Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen mtrr: Kill some unneccessary includes Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen mtrr: Use generic_validate_add_page() Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen mtrr: Implement xen_get_free_region() Jeremy Fitzhardinge
2009-02-28 1:59 ` [PATCH] xen mtrr: Add xen_{get,set}_mtrr() implementations Jeremy Fitzhardinge
2009-02-28 5:28 ` [PATCH] xen: core dom0 support Andrew Morton
2009-02-28 6:52 ` Jeremy Fitzhardinge
2009-02-28 7:20 ` Ingo Molnar
2009-02-28 8:05 ` Jeremy Fitzhardinge
2009-02-28 8:36 ` Ingo Molnar
2009-02-28 9:57 ` Jeremy Fitzhardinge
2009-03-02 9:26 ` Gerd Hoffmann
2009-03-02 12:04 ` Ingo Molnar
2009-03-02 12:26 ` Gerd Hoffmann
2009-02-28 12:09 ` Nick Piggin
2009-02-28 18:11 ` [Xen-devel] " Jody Belka
2009-02-28 18:15 ` Andi Kleen
2009-03-01 23:38 ` Jeremy Fitzhardinge
2009-03-02 0:14 ` Andi Kleen
2009-03-01 23:27 ` Jeremy Fitzhardinge
2009-03-02 6:37 ` Nick Piggin
2009-03-02 8:05 ` Jeremy Fitzhardinge
2009-03-02 8:19 ` Nick Piggin
2009-03-02 9:05 ` Jeremy Fitzhardinge
2009-03-04 17:34 ` Anthony Liguori
2009-03-04 17:38 ` Jeremy Fitzhardinge
2009-03-05 10:59 ` [Xen-devel] " George Dunlap
2009-03-05 14:37 ` Anthony Liguori
2009-03-04 17:31 ` Anthony Liguori
2009-03-04 19:03 ` Anthony Liguori
2009-03-04 19:16 ` H. Peter Anvin
2009-03-04 19:33 ` Anthony Liguori
2009-02-28 16:14 ` Andi Kleen
2009-03-01 23:34 ` Jeremy Fitzhardinge
2009-03-01 23:52 ` H. Peter Anvin
2009-03-02 0:08 ` Jeremy Fitzhardinge
2009-03-02 0:14 ` H. Peter Anvin
2009-03-02 0:42 ` Jeremy Fitzhardinge
2009-03-02 0:46 ` H. Peter Anvin
2009-03-02 0:10 ` Andi Kleen
2009-02-28 8:42 ` Ingo Molnar
2009-02-28 9:46 ` Jeremy Fitzhardinge
2009-03-02 12:08 ` Ingo Molnar
2009-03-07 9:06 ` Jeremy Fitzhardinge
2009-03-08 11:01 ` Ingo Molnar
2009-03-08 21:56 ` H. Peter Anvin
2009-03-08 22:06 ` Ingo Molnar
2009-03-08 22:08 ` H. Peter Anvin
2009-03-08 22:12 ` Ingo Molnar
2009-03-09 18:06 ` Jeremy Fitzhardinge
2009-03-10 12:44 ` Ingo Molnar [this message]
2009-03-10 12:49 ` Nick Piggin
2009-03-05 13:52 ` Morten P.D. Stevens
2009-03-08 14:25 ` Manfred Knick
2009-03-09 19:51 ` Morten P.D. Stevens
2009-03-09 20:00 ` Morten P.D. Stevens
2009-03-11 19:58 devzero
2009-03-14 1:08 ` Morten P.D. Stevens
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