> I'm a little confuised.. I just tried to run this on my nexgen-90, and it
^^^^^^
This chip is the NexGen-P90. To almost all programs, it looks like a
'386. It was the first pentium clone on the market - released before the
rdtsc instruction was known of - thus the patch fails. As far as I know,
it only knows '386 ('486?) instructions. It was originally designed in
the days of the '386, but was delayed.
> gave me this:
>
> [root@metallica /root]# ./mhz.estimate
> Illegal Instruction (core dumped)
>
> Now, does this program only work on pentium's, i'm a little confused.
>
> -Robg
>
> On Sat, 27 Dec 1997, Robert Woodcock wrote:
>
> > Phile Brutsche wrote:
> > >On another note, I just looked at your patch. It uses the rdtsc
> > >instruction; this instruction does not exist on anything less than a
> > >Pentium. I'm not sure what the kernel would do on '486 or '386, but it
> > >would'nt be pretty. A better solution for this would be to time the bsf
> > >instruction on those chips. I have source in C and assembly if you need
> > >help.
> >
> > Can you mail that to me at the return address?
> >
> > Currently I'm using this userspace code I pieced together myself (well,
> > not the rdtsc function, I ripped that from the I/O Port Programming HOWTO)
> > which is so consistent that it's making me wonder if my motherboard clock
> > chip is a little bit off and is actually running my CPU at 99.57mhz
> > instead of 100. (I gave this program to several other people with pentiums
> > and it seems to consistently report either high and low depending on the
> > system.)
> >
> > mercury:~$ (while :; do mhz.estimate; done)
> > 99.569984 MHz processor.
> > 99.569979 MHz processor.
> > 99.570001 MHz processor.
> > 99.569946 MHz processor.
> >
> > Kinda makes you wonder about those motherboard benchmarks where all the
> > motherboards are within a few tenths of a percent of each other. :)
> >
> > Compile as usual, gcc mhz.estimate.c -o mhz.estimate.
> >
> > #include <stdio.h>
> > #include <sys/time.h>
> >
> > /* returns number of clock cycles since last reboot */
> > __inline__ unsigned long long int rdtsc()
> > {
> > unsigned long long int x;
> > __asm__ volatile (".byte 0x0f, 0x31" : "=A" (x));
> > return x;
> > }
> >
> > main ()
> > {
> > struct timezone tz;
> > struct timeval tvstart, tvstop;
> > unsigned long long int cycles[2]; /* gotta be 64 bit */
> > unsigned int microseconds; /* total time taken */
> >
> > bzero(&tz, sizeof(tz));
> >
> > /* get this function in cached memory */
> > gettimeofday(&tvstart, &tz);
> > cycles[0] = rdtsc();
> > gettimeofday(&tvstart, &tz);
> >
> > /* we don't trust that this is any specific length of time */
> > sleep(1);
> >
> > cycles[1] = rdtsc();
> > gettimeofday(&tvstop, &tz);
> > microseconds = ((tvstop.tv_sec-tvstart.tv_sec)*1000000) +
> > (tvstop.tv_usec-tvstart.tv_usec);
> >
> > printf("%f MHz processor.\n",
> > (float)(cycles[1]-cycles[0])/microseconds);
> > }
> > --
> > Robert Woodcock - robert@olex.com
> > All I want is a warm bed and a kind word and unlimited power.
> > -- Ashleigh Brilliant
> >
>
>
----------------------------------------------------------------------
Phil Brutsche
"Be of stout heart, Number One. We've handled the Borg. We can
certainly handle Admiral Jellico." - Jean-Luc Picard
----------------------------------------------------------------------