Message-ID: <533759.75961.qm@web25504.mail.ukl.yahoo.com>
Date: Thu, 30 Sep 2010 09:38:33 +0000 (GMT)
From: Marco Atzeri <marco_atzeri@yahoo.it>
Subject: R: Cygwin 1.7.7 fork/exec performance MUCH slower than 1.5.25
To: cygwin@cygwin.com, =?iso-8859-1?Q?SZAB=D3_Gergely?= <szg@subogero.com>
In-Reply-To: <1285824109.1725.2.camel@OG3>
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--- Gio 30/9/10, SZAB=D3 Gergely  ha scritto:

> Hello,
>=20
> we have a Cygwin-based build system for an embedded
> project.
> Build performance has deteriorated terribly since we
> upgraded to 1.7.x from 1.5.25.
>=20
> I've created 3 shell-scripts to benchmark 1.5.25 and 1.7.7
> against each other.
> - null=A0 =A0 : read file "inp" line by line, write
> to /dev/null.
> - builtin : write each line to file "out", only
> bash-builtins used (no fork)
> - fork=A0 =A0 : do some substitution for each line
> with sed (huge number of forks)
>=20
> Results:
> - null=A0 =A0 : 1.7.7 is about 5 times faster
> - builtin : 1.7.7 is slightly faster
> - fork=A0 =A0 : 1.7.7 is 5 times SLOWER !!!
>=20
> All measurements were made with the "time" command.
> The attached results.txt lists the "real" times.
>=20
> I've also attached the 3 shell-scripts (null, builtin,
> fork).
> Input file "inp" is also attached.
>=20
> Also see the cygcheck_xxx.out files for both Cygwin
> versions.
>=20
> Some notes:=20
> both cygwin versions use the same /home, mounted from
> "D:\Documents and Settings",

I bet is a network/acl issues.=20
I suggest to create a real home on "/home"

> so all user-level config-files are shared between the
> Cygwin versions.
>=20
> Cygwin 1.7.7 is basically unusable at the moment.
> Any ideas why it's so much slower at spawning processes? Or
> is it the pipes? Am I doing something wrong?
>=20
> And more importantly: is there an easy way to fix this?
>=20
> Thanks in advance for any help!
>=20
> Best regards
> Gergely Szab=F3
>=20

testing on /tmp/benchmark with XPS P2

cygwin 1.7.8s 20100924

$ time ./fork

real    1m12.856s
user    0m52.480s
sys     1m6.423s


cygwin 1.5.25-15

$ time ./fork

real    1m7.969s
user    0m52.992s
sys     1m11.583s


So no difference

Marco


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