gjh@otter.hpl.hp.com (Graham Higgins) (12/08/89)
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
------------------------------------------------------------------
Disclaimer: My opinions above are exactly that, mine and opinions.
------------------------------------------------------------------dag@per2.UUCP (Daniel A. Glasser) (12/20/89)
In article <570049@otter.hpl.hp.com>, gjh@otter.hpl.hp.com (Graham Higgins) writes: [edited for brevity] > 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. > Can anyone provide me with an appropriate value for HZ for an (unaccelerated) > ST? I cannot tell you for sure about the particular times() function in the particular library (if I were at home, I could), but the ST's system 'tick' clock is a 200Hz clock. Try that value out and see if the results seem plausible. Daniel -- _____________________________________________________________________________ Daniel A. Glasser One of those things that goes uwvax!per2!dag "BUMP!!!(ouch)" in the night. ---Persoft, Inc.---------465 Science Drive-------Madison, WI 53711-----------