From: Andreas Mohr <andi@lisas.de>
To: Andreas Mohr <andi@lisas.de>
Cc: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>,
Corrado Zoccolo <czoccolo@gmail.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-acpi@vger.kernel.org
Subject: Re: Dynamic configure max_cstate
Date: Tue, 28 Jul 2009 16:03:08 +0200 [thread overview]
Message-ID: <20090728140308.GA17543@rhlx01.hs-esslingen.de> (raw)
In-Reply-To: <20090728101135.GA22358@rhlx01.hs-esslingen.de>
On Tue, Jul 28, 2009 at 12:11:35PM +0200, Andreas Mohr wrote:
> As a very quick test, I tried a
> while :; do :; done
> loop in shell and renicing shell to 19 (to keep my CPU out of ACPI idle),
> but bonnie -s 100 results initially looked promising yet turned out to
> be inconsistent. The real way to test this would be idle=poll.
> My test system was Athlon XP with /proc/acpi/processor/CPU0/power
> latencies of 000 and 100 (the maximum allowed value, BTW) for C1/C2.
OK, I just tested it properly.
Rebooted, did 5 bonnie -s 100 with ACPI idle, rebooted and did another 5
bonnie -s 100 with idle=poll, results:
$ cat bonnie_ACPI_* /tmp/line bonnie_poll_*
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
1* 100 20084 95.3 19037 9.5 12286 4.7 18074 99.6 581752 96.6 28792.3 93.6
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
1* 100 19235 93.5 24591 11.8 13916 4.3 17934 99.8 604429 100.3 27993.8 98.0
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
1* 100 17221 86.3 30591 16.1 15404 5.4 18689 99.3 593296 92.7 28146.0 98.5
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
1* 100 20254 99.3 110095 55.9 15722 6.1 17901 99.5 601185 99.8 28675.5 100.4
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
1* 100 18274 88.5 106909 53.2 10614 4.1 18759 99.7 598833 99.4 28461.6 92.5
========
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
1* 100 15274 98.2 20206 9.7 17286 7.3 18055 99.4 608112 101.0 28424.0 99.5
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
1* 100 20545 99.1 25332 12.6 16392 6.1 17957 99.4 606706 100.7 27906.8 90.7
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
1* 100 20482 99.2 30907 13.6 17585 6.2 17867 99.1 608090 101.0 27919.1 97.7
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
1* 100 20863 99.4 138383 66.2 18945 7.6 17938 99.5 581421 96.5 27094.6 94.8
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
1* 100 20821 98.8 156821 70.4 11536 4.4 18747 99.0 603556 100.2 27677.8 96.9
And these values (cumulative) result in:
ACPI poll
Per Char 95068 97985 +3.06%
Block 291223 371649 +27.62%
Rewrite 67942 81744 +20.31%
Per Char 91357 90564 -0.87%
Block 2979495 3007885 +0.95%
RndSeek 142069.2 139022.3 -2.1%
average: +8.16%
Now the question is how much is due to idle state entry/exit latency
and how much is due to ACPI idle/wakeup code path execution.
Still, an average of +8.16% during 5 test runs each should be quite some incentive,
and once there's a proper "idle latency skipping during expected I/O replies"
even with idle/wakeup code path reinstated we should hopefully be able to keep
some 5% improvement in disk access.
Andreas Mohr
next prev parent reply other threads:[~2009-07-28 14:03 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-27 5:30 Dynamic configure max_cstate Zhang, Yanmin
2009-07-27 7:33 ` Andreas Mohr
2009-07-28 2:42 ` Zhang, Yanmin
2009-07-28 7:20 ` Corrado Zoccolo
2009-07-28 9:00 ` Zhang, Yanmin
2009-07-28 10:11 ` Andreas Mohr
2009-07-28 14:03 ` Andreas Mohr [this message]
2009-07-28 17:35 ` ok, now would this be useful? (Re: Dynamic configure max_cstate) Andreas Mohr
2009-07-29 8:20 ` Dynamic configure max_cstate Zhang, Yanmin
2009-07-31 3:43 ` Robert Hancock
2009-07-31 7:06 ` Zhang, Yanmin
2009-07-31 8:07 ` Andreas Mohr
2009-07-31 14:40 ` Andi Kleen
2009-07-31 14:56 ` Michael S. Zick
2009-07-31 17:37 ` Pallipadi, Venkatesh
2009-07-31 15:14 ` Len Brown
2009-07-30 6:28 ` Zhang, Yanmin
2009-07-28 19:25 ` Len Brown
2009-07-29 0:17 ` Len Brown
2009-07-29 8:00 ` Andreas Mohr
2009-07-28 19:47 ` Len Brown
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