Date: Sun, 23 Sep 2001 21:19:30 +0200 From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: Matt Dillon <dillon@earth.backplane.com> Cc: David Greenman <dg@root.com>, Seigo Tanimura <tanimura@r.dl.itc.u-tokyo.ac.jp>, bright@wintelcom.net, hackers@FreeBSD.ORG Subject: Re: Conclusions on... was Re: More on the cache_purgeleafdirs() routine Message-ID: <1620.1001272770@critter> In-Reply-To: Your message of "Sat, 22 Sep 2001 23:42:25 PDT." <200109230642.f8N6gPj84955@earth.backplane.com>
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I ran one of my trivial benchmarks here: "make -j 12 buildworld"
on a dual 866MHz P3 with 640M RAM.
Most of the stuff reported by "/usr/bin/time -l" here is useless:
almost all the numbers are all inside the standard deviation I have
recorded for them on this box.
Block input operations is the one notable exception and it tells a
very interesting story: Matts patch results in a 4% increase, but
combined with vmdirioenable it results in a 21.5% decrease.
That's pretty darn significant: one out of every five I/O have
been saved.
The reason it has not manifested itself in the "real" number is
probably the high degree of parallelism in the task which practically
ensures that the CPU will not go idle.
I suggest we let Matt's patch depend on the vmiodirenable sysctl
and change the default for that.
If there are no bad side effects found in the next couple of months,
then kill the sysctl and lets be done with it.
Poul-Henning
-current | Matts patch | Matts patch
| | vmiodirenable=1
-------------+-------------+-------------------------------------------
2206.27| 2277.97| 2190.35|real
2118.62| 2119.07| 2128.68|user
828.77| 825.03| 835.24|system
15220 | 15220 | 15216 |maximum resident set size
1006 | 1006 | 1005 |average shared memory size
1036 | 1035 | 1034 |average unshared data size
128 | 128 | 128 |average unshared stack size
10800112 | 10812895 | 10799144 |page reclaims
2530 | 3002 | 2686 |page faults
0 | 0 | 0 |swaps
36971 | 38462 | 29030 |block input operations
6694 | 6637 | 6610 |block output operations
0 | 0 | 0 |messages sent
0 | 0 | 0 |messages received
6 | 6 | 6 |signals received
17857329 | 17161716 | 17914470 |voluntary context switches
843181 | 898530 | 778408 |involuntary context switches
-------------+-------------+-------------------------------------------
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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