[Linux-ia64] Performance Monitor Internals:

[Linux-ia64] Performance Monitor Internals:

[Jonathan Case Nicklin]

[-- Attachment #1: Type: text/plain, Size: 479 bytes --]

Greetings,

    My colleague and I are working with the IA64 performance monitors
and would like to get involved
    or at least learn more about the development effort of the syscall
interface and its internals. Has
    any person or group been assigned to this task? If so, please email
me or the list so we can
    possibly collaborate on the design/implementation effort.

Sincerely,
Jonathan Case Nicklin / John Baboval

Mission Critical Linux
www.missioncriticallinux.com


[-- Attachment #2: Type: text/html, Size: 760 bytes --]

Re: [Linux-ia64] Performance Monitor Internals:

[Stephane Eranian]

Hi,

> 
>     My colleague and I are working with the IA64 performance monitors
> and would like to get involved
>     or at least learn more about the development effort of the syscall
> interface and its internals. Has
>     any person or group been assigned to this task? If so, please email
> me or the list so we can
>     possibly collaborate on the design/implementation effort.
> 

I am currently working on the perfmon support for Linux/ia64 as you may
have seen for the recent patches.  The goal is to support the entire set
of features of the Itanium PMU including EARS and BTB and not just counting.
Also support is planned for per process AND system-wide monitoring on
both UP and SMP systems.

So I you have any ideas, concerns or want to contribute something, please
feel free to contact me.

Regards,

+--------------------------------------------------------------------+
| Ste'phane ERANIAN                       | Email eranian@hpl.hp.com |
| Hewlett-Packard Laboratories            |                          |
| 1501, Page Mill Road MS 1U-15           |                          |
| Palo  Alto, CA 94303-096                |                          |
| USA                                     |                          |
| Tel : (650) 857-7174                    |                          |
| Fax : (650) 857-5548                    |                          |
+--------------------------------------------------------------------+

Re: [Linux-ia64] Performance Monitor Internals:

[Ross Ridge]

> I am currently working on the perfmon support for Linux/ia64 as you
may
> have seen for the recent patches.  The goal is to support the entire
set
> of features of the Itanium PMU including EARS and BTB and not just
counting.
> Also support is planned for per process AND system-wide monitoring
on
> both UP and SMP systems.
>
> So I you have any ideas, concerns or want to contribute something,
please
> feel free to contact me.

I'm also interested in using the performance monitor, but my only
concern is if user processes will able to access the performance
counters directly with a "mov 1,PMD[r2]" instruction, instead of
having to use some sort of kernel service to access the counter.
Essentially, all I'm looking for is a replacement for the IA-32's
"RDTSC" instruction in the code I'm porting.

                                          Ross Ridge

Re: [Linux-ia64] Performance Monitor Internals:

[David Mosberger]

>>>>> On Thu, 9 Nov 2000 10:40:32 -0500, "Ross Ridge" <ross@sitraka.com> said:

  Ross> I'm also interested in using the performance monitor, but my
  Ross> only concern is if user processes will able to access the
  Ross> performance counters directly with a "mov 1,PMD[r2]"
  Ross> instruction, instead of having to use some sort of kernel
  Ross> service to access the counter.  Essentially, all I'm looking
  Ross> for is a replacement for the IA-32's "RDTSC" instruction in
  Ross> the code I'm porting.

You can use the attached code.

	--david

static __inline__ unsigned long
ia64_get_itc (void)
{
	unsigned long result;

	__asm__ __volatile__("mov %0=ar.itc" : "=r"(result) :: "memory");
	while (__builtin_expect ((int) result = -1, 0))
		__asm__ __volatile__("mov %0=ar.itc" : "=r"(result) :: "memory");
	return result;
}

Re: [Linux-ia64] Performance Monitor Internals:

[Pete Wyckoff]

davidm@hpl.hp.com said:
> static __inline__ unsigned long
> ia64_get_itc (void)
> {
> 	unsigned long result;
> 
> 	__asm__ __volatile__("mov %0=ar.itc" : "=r"(result) :: "memory");
> 	while (__builtin_expect ((int) result = -1, 0))
> 		__asm__ __volatile__("mov %0=ar.itc" : "=r"(result) :: "memory");
> 	return result;
> }

Why is it no good to return result when it satisfies:

    (result & 0xffffffff) = 0xffffffff

?  Curiosity.

		-- Pete