From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com,
x86@kernel.org, linux-kernel@vger.kernel.org,
xen-devel@lists.xensource.com
Subject: Re: [PATCH] x86 fixes for 3.3 impacting distros (v1).
Date: Mon, 20 Feb 2012 22:32:31 -0500 [thread overview]
Message-ID: <20120221033231.GA3776@phenom.dumpdata.com> (raw)
In-Reply-To: <1329786103.25686.48.camel@gandalf.stny.rr.com>
On Mon, Feb 20, 2012 at 08:01:43PM -0500, Steven Rostedt wrote:
> On Fri, 2012-02-10 at 10:34 -0500, Konrad Rzeszutek Wilk wrote:
> > 66 66 66 90 data32 data32 xchg %ax,%ax
> >
> > [the 66 66 .. is 'nop']. Looks good right? Well, it does work very well on Intel
> > (used an i3 2100), but on AMD A8-3850 it hits a performance wall - that I found out
> > is a result of CONFIG_FUNCTION_TRACER (too many nops??) being compiled in (but the tracer
> > is set to the default 'nop'). If I disable that specific config option the numbers
> > are the same as the baseline (with CONFIG_FUNCTION_TRACER disabled) on the AMD box.
> > Interestingly enough I only see these on AMD machines - not on the Intel ones.
>
> All paravirt ops should be labeled with "notrace" so that function
> tracer does not trace those functions. Have you annotated your new
> paravirt ops with notrace?
No. I hadn't realized that flag existed until your email a couple of days ago - I hadn't
had a chance to see if the notrace would solve this. But let me do that and get
back on this.
next prev parent reply other threads:[~2012-02-21 3:32 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-10 15:34 [PATCH] x86 fixes for 3.3 impacting distros (v1) Konrad Rzeszutek Wilk
2012-02-10 15:34 ` [PATCH] x86/cpa: Use pte_attrs instead of pte_flags on CPA/set_p.._wb/wc operations Konrad Rzeszutek Wilk
2012-02-21 1:01 ` [PATCH] x86 fixes for 3.3 impacting distros (v1) Steven Rostedt
2012-02-21 1:38 ` H. Peter Anvin
2012-02-21 3:32 ` Konrad Rzeszutek Wilk [this message]
2012-02-22 2:53 ` Jason Garrett-Glaser
2012-05-10 15:34 ` [Xen-devel] " Konrad Rzeszutek Wilk
2012-06-27 23:17 ` Cyclonus J
2012-06-28 14:28 ` Konrad Rzeszutek Wilk
2012-06-28 14:42 ` H. Peter Anvin
2012-06-28 15:38 ` Jan Beulich
2012-06-29 21:52 ` Cyclonus J
2012-06-29 22:29 ` H. Peter Anvin
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