Date: Wed, 4 Sep 2002 12:52:17 -0700 (PDT) From: Poul-Henning Kamp <phk@FreeBSD.org> To: cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: cvs commit: src/sys/i386/i386 elan-mmcr.c Message-ID: <200209041952.g84JqHZG022386@freefall.freebsd.org>
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phk 2002/09/04 12:52:17 PDT
Modified files:
sys/i386/i386 elan-mmcr.c
Log:
On the ElanSC520 CPU use general purpose timer#2 as timecounter.
This is a vast improvement over the i8254, since it is a simple
memory load rather than a comples sequence of interrupt blocking,
multiple input/output instructions, and wrap-around detection.
I have not bothered to time the fundamental timecounter get routine,
but gettimeofday(2) is 10% faster with the ELAN timecounte.
The downside is that HZ=100 is not enough, 150 or more recommended,
I use 250 myself.
Revision Changes Path
1.4 +19 -0 src/sys/i386/i386/elan-mmcr.c
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