From: Andi Kleen <ak@linux.intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Andi Kleen <andi@firstfloor.org>,
x86@kernel.org, linux-kernel@vger.kernel.org, eranian@google.com
Subject: Re: [PATCH 2/4] x86: Track minimum microcode revision globally v2
Date: Wed, 13 Jun 2012 14:51:22 -0700 [thread overview]
Message-ID: <20120613215122.GF32604@tassilo.jf.intel.com> (raw)
In-Reply-To: <1339623321.8980.66.camel@twins>
> This would really much better live in common code where it can be
> preemptible in some sites. There really is no need for this to be
> non-preemptible.
Okay I can look. But you're really optimizing the wrong things here.
Even on a 4096 CPU system such a loop is miniscule compared to the
actual cost of the microcode update, which stops the complete CPU
for quite some time.
Basically microcode updates and low latency are incompatible
Don't do it when it hurts.
Unfortunately i'm changing all the callers two patches further,
so it'll be messy too.
-Andi
--
ak@linux.intel.com -- Speaking for myself only
next prev parent reply other threads:[~2012-06-13 21:51 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-13 20:20 Updated microcode tracking and PEBS workaround patchkit Andi Kleen
2012-06-13 20:20 ` [PATCH 1/4] x86: Do microcode updates at CPU_STARTING, not CPU_ONLINE Andi Kleen
2012-06-14 11:00 ` Borislav Petkov
2012-06-14 13:54 ` Henrique de Moraes Holschuh
2012-06-13 20:20 ` [PATCH 2/4] x86: Track minimum microcode revision globally v2 Andi Kleen
2012-06-13 21:34 ` Peter Zijlstra
2012-06-13 21:39 ` Andi Kleen
2012-06-14 8:56 ` Ingo Molnar
2012-06-13 21:35 ` Peter Zijlstra
2012-06-13 21:51 ` Andi Kleen [this message]
2012-06-14 9:10 ` Borislav Petkov
2012-06-14 13:36 ` Andi Kleen
2012-06-14 12:20 ` Borislav Petkov
2012-06-14 12:37 ` Borislav Petkov
2012-06-13 20:20 ` [PATCH 3/4] perf, x86: check ucode before disabling PEBS on SandyBridge v3 Andi Kleen
2012-06-13 21:30 ` Peter Zijlstra
2012-06-13 21:34 ` Andi Kleen
2012-06-13 21:36 ` Peter Zijlstra
2012-06-13 22:34 ` Andi Kleen
2012-06-13 20:20 ` [PATCH 4/4] x86: Detect model/family mismatches for common microcode revision Andi Kleen
2012-06-14 18:02 ` Borislav Petkov
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