Date: Mon, 9 May 2005 15:33:28 -0400 From: Ewan Todd <ewan@mathcode.net> To: Daniel Eischen <deischen@freebsd.org> Cc: freebsd-stable@freebsd.org Subject: Re: Performance issue Message-ID: <20050509193328.GJ281@mathcode.net> In-Reply-To: <Pine.GSO.4.43.0505091428460.27904-100000@sea.ntplx.net> References: <2B4490FF-FEFD-473F-BDF0-293C468A55B9@FreeBSD.org> <Pine.GSO.4.43.0505091428460.27904-100000@sea.ntplx.net>
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> >
> > I ran ktrace(1) on it, and it appears that python keeps calling
> > sigprocmask() continually:
> >
> > 673 python 0.000007 CALL sigprocmask(0x3,0,0x811d11c)
> > 673 python 0.000005 RET sigprocmask 0
> > 673 python 0.000009 CALL sigprocmask(0x1,0,0x8113d1c)
> > 673 python 0.000005 RET sigprocmask 0
> > etc..
> >
> > This explains why it's using so much system time. Now the question is
> > why is python doing this?
>
> I don't know what python's doing, but it might not be calling
> sigprocmask directly. There are a few libc functions that use
> sigprocmask:
>
> db/btree/
> db/hash/
> pselect(),
> setmode(),
> {sig}setjmp(), {sig}longjmp(),
> grantpt(),
> system()
>
> to name a few. Python may also be using other libraries which
> use sigprocmask().
>
OK, it's a python thing. Whatever python is doing, perl, ruby and C
are not.
4.10 box
perl: 247.66 real 243.29 user 0.63 sys
ruby: 312.36 real 308.49 user 0.17 sys
C: 2.74 real 2.72 user 0.00 sys
C(n=100million):
42.87 real 40.80 user 0.36 sys
python: 130.78 real 129.86 user 0.11 sys
5.3 box
perl: 128.73 real 127.13 user 0.25 sys
ruby: 159.72 real 158.19 user 0.21 sys
C: 1.62 real 1.59 user 0.01 sys
C(n=100million):
28.33 real 27.97 user 0.12 sys
python: 104.52 real 69.36 user 33.89 sys
So I'm getting the 2x performance enhancement I expected from the
processor (except for C) from these other languages.
The heapsort test is from
http://shootout.alioth.debian.org/great/benchmark.php?test=heapsort&lang=all&sort=fullcpu
(along with a score or more other languages), and there are a bunch of
other tests at
http://shootout.alioth.debian.org/great/index.php
I'll notify the python porter unless (s)he knows already.
Thanks to everyone who helped. It would have taken me ages. No-one
indicated that this was an inappropriate use of the list, but I
apologise if anyone felt that way.
-e
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