Date: Wed, 6 Feb 2002 00:10:05 -0500 From: Garance A Drosihn <drosih@rpi.edu> To: current@FreeBSD.org Subject: Performance of -current vs -stable Message-ID: <20020212021138.D3FC89F260@okeeffe.bestweb.net>
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With 4.5-release out the door, I thought I'd start trying to use
5.0-current on my "main freebsd machine" instead of 4.x-stable. I
figure at some point we (as developers) have got to try to migrate
to that release as much as possible.
I had been doing some stuff with 5.0-current at home. That seemed
a bit slow, but I didn't think too much of it as the home machine is
a single-CPU Duron-based machine (600 Mhz). while the machine at work
is a dual-CPU Pentium-3 machine (650 MHz). The office machine also
has more RAM, so obviously the home machine would be slower.
But switching to current on the office machine is also considerably
slower. I wasn't expecting "faster", but I'm wondering if other
people are also seeing it as much slower, or if I've just got some
other odd problem hitting me.
One simple test I tried was that I have a copy of the freebsd cvs
repository in /usr/cvs/free, on it's own partition. Each system
has it's own /usr/src, of course. I cvsup'ed /usr/cvs/free, and
then did a
time cvs status >/dev/null
in each /usr/src, on each system. (that command is just for this
timing test, I usually do more useful commands at that point!).
On current On stable
---------- ----------
real 7m 43.392s 4m 53.100s in /usr/src for current
user 0m 11.692s 0m 4.203s
sys 3m 4.601s 0m 2.248s
real 6m 40.322s 2m 39.361s in /usr/src for stable
user 0m 10.531s 0m 6.653s
sys 4m 28.863s 0m 9.480s
I realize this example isn't terribly detailed, but it seems to
match what I "feel" when doing any major work on current. I'm
used to a 'make -j5 buildworld' taking between 42 and 45 minutes
for stable on my office machine, but the few times I've rebuilt
-current, it's taking more like three and a half hours. That is
quite a hit.
This current system was initially installed in late-december, doing
a full system-install (booting off a CD, newfs'ing the partitions,
etc). So, it should have picked up all the recent filesystem
improvements (dirprefs, etc) when laying out the files, and even if
that wasn't true this test is done using the exact same directories
as source & destination for the stable vs current tests.
Could it be due to the DDB, INVARIANTS & WITNESS options in the
kernel? If it is that's fine with me, I'm just wondering where
that magnitude of a slowdown would be coming from.
Anything else I should check? I realize there's about a million
differences between the two branches, and there might also be
something about my machine's setup which is a major culprit here.
I'm just looking for a basic idea of what other people have been
seeing for performance when they run current.
--
Garance Alistair Drosehn = gad@eclipse.acs.rpi.edu
Senior Systems Programmer or gad@freebsd.org
Rensselaer Polytechnic Institute or drosih@rpi.edu
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