linux-kernel - [PATCH 3/3] optimize get_cycles

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Message-ID: <20070219191139.GD6083@amd.com>
Date:	Mon, 19 Feb 2007 20:11:39 +0100
From:	"Joerg Roedel" <joerg.roedel@....com>
To:	discuss@...-64.org
cc:	linux-kernel@...r.kernel.org, "Andi Kleen" <ak@...e.de>
Subject: [PATCH 3/3] optimize get_cycles_sync for Linux as KVM guest

From: Joerg Roedel <joerg.roedel@....com>

This patch modifies the get_cycles_sync() function on i386 and x86_64 to
use the RDTSCP (if it is available) instruction to synchronize with the
CPU core and not CPUID. This is especially usefull when running Linux as
a KVM guest because CPUID is intercepted and will cause a VMEXIT there.

Signed-off-by: Joerg Roedel <joerg.roedel@....com>

-- 
Joerg Roedel
Operating System Research Center
AMD Saxony LLC & Co. KG

View attachment "get_cycles_sync-optimization.patch" of type "text/plain" (1869 bytes)