Article View: comp.sys.atari.st
Article #39460GCC times(2) & #define HZ tech query
From: Graham Higgins
Date: Fri, 08 Dec 1989 12:38
Date: Fri, 08 Dec 1989 12:38
75 lines
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3193 bytes
Can anyone enlighten me on the following technical query?
The C system call "times(2)" -- my SysV manual states:
"The times are in units of 1/HZ seconds, where HZ is processor dependent (see
<sys/param.h>)."
The sys/param.h from J.Bammi's port of GCC to the ST doesn't have a definition
for HZ.
My local Sun's sys/param.h file defines it as:
#define HZ 60
/* ticks/second according to syscalls that return values in ticks */
My HP9000/350 defines it as:
#define HZ 50
/* Ticks/second of the clock (in kernel land) */
Can anyone provide me with an appropriate value for HZ for an (unaccelerated)
ST?
Background ...
I have a Prolog benchmark indicating a (literally) incredibly slow ST
performance level and here there's a caveat, the benchmark README file contains
the following warning:
WARNING: Naive reverse is the classical benchmark for
computing "LIPS" (Logical Inferences Per Second),
but it's such a small benchmark that LIPS numbers
so obtained may not necessarily reflect overall system
performance, and should be taken with a large pinch of salt.
*However* -- on my HP9000/350, the same benchmark (run by the same Prolog)
indicates a performance level of 30KLips whereas the ST can apparently run only
1.5KLips!. I was surprised at (and suspicious of) the size of the difference in
apparent performance. I know they said "should be taken with a large pinch of
salt", but this requires a cartload!
Crude stopwatch timing indicates that the ST performs the benchmark in ~40
secs, the HP9000/350 in ~10 secs. From those crude timings, the ST benchmark
indicator should be around 5 to 6KLips, not 1.5KLips. So, perhaps a problem
with times(2) ??
The Prolog is SUNY/UArizona's StonyBrook Prolog, GCC-cross-compiled to ST. The
benchmark relies upon a "cputime" function ---
int msec;
struct tms t;
times(&t);
msec = t.tms_utime * 1000 / 60;
which is supposed to return the cpu time in millseconds.
Can anyone tell me is this appropriate for GCC for the ST? --- it *looks*
plausible, but the times don't seem to pan out properly?
If I can fix this, I'll make the ST port of Stony Brook Prolog available.
Cheers,
Graham
======
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Graham Higgins | Phone: (0272) 799910 x 24060
Hewlett-Packard Labs | gray@hpl.hp.co.uk
Bristol | gray%hplb.uucp@ukc.ac.uk
U.K. | gray@hplb.hpl.hp.com
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Disclaimer: My opinions above are exactly that, mine and opinions.
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Path: arc1-ca.pugleaf.net!utzoo!attcan!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!wuarchive!decwrl!ucbvax!hplabs!otter!gjh From: gjh@otter.hpl.hp.com (Graham Higgins) Newsgroups: comp.sys.atari.st Subject: GCC times(2) & #define HZ tech query Message-ID: <570049@otter.hpl.hp.com> Date: 8 Dec 89 12:38:37 GMT Organization: Hewlett-Packard Laboratories, Bristol, UK. Lines: 75