[Linux-ia64] Instruction Execution

[Linux-ia64] Instruction Execution

[Mattox, Dave]

I just got my Itanium Machine in and after installing Linux (no problems
with that, good work guys), I tried some timings.

I ran a loop 666,000,000 times and it appears that each bundle is taking 3
seconds to execute. So this means 3 cycles per bundle,
or 1 cycle per instruction. Is the Lion SDV Machine executing instructions
serially? If it is, is it Linux setting this, or are the beta chips disabled
in some manner?

Thanks in advance for help on this,
Dave Mattox

Re: [Linux-ia64] Instruction Execution

[David Mosberger]

>>>>> On Tue, 17 Oct 2000 09:51:51 -0700, "Mattox, Dave" <DMattox@UNITECH.COM> said:

  Dave> I just got my Itanium Machine in and after installing Linux
  Dave> (no problems with that, good work guys), I tried some timings.

  Dave> I ran a loop 666,000,000 times and it appears that each bundle
  Dave> is taking 3 seconds to execute. So this means 3 cycles per
  Dave> bundle, or 1 cycle per instruction. Is the Lion SDV Machine
  Dave> executing instructions serially? If it is, is it Linux setting
  Dave> this, or are the beta chips disabled in some manner?

Make sure "Multidispersal" is enabled in the advanced chipset
configuration menu of the firmware (BIOS).

	--david

Re: [Linux-ia64] Instruction Execution

[Francis Galiegue]

On Tue, 17 Oct 2000, Mattox, Dave wrote:

> 
> I ran a loop 666,000,000 times and it appears that each bundle is taking 3
> seconds to execute. So this means 3 cycles per bundle,
> or 1 cycle per instruction. Is the Lion SDV Machine executing instructions
> serially? If it is, is it Linux setting this, or are the beta chips disabled
> in some manner?
> 

ia64 does not do instruction reordering, at least this is what I've heard, and
nothing which I have read until now seems to deny this. All insn ordering for
faster execution should therefore be done by the compiler.

No URL to give you, sorry...

-- 
Francis Galiegue, fg@mandrakesoft.com
"Programming is a race between programmers, who try and make more and more
idiot-proof software, and universe, which produces more and more remarkable
idiots. Until now, universe leads the race"  -- R. Cook

Re: [Linux-ia64] Instruction Execution

[Jim Wilson]

Instruction timing depends on what instructions you are executing, and where
the stop bits are.  If you are running a loop with FP instructions, or a loop
with a lot of serial instruction dependencies, then 1 cycle per instruction
is certainly possible.  Since you didn't give any assembly code samples,
it isn't possible to tell if the loop was poorly optimized or not.

Jim

RE: [Linux-ia64] Instruction Execution

[Mattox, Dave]

That was the problem, its now working exactly as I expected :)

Thanks for the help everyone,
Dave

-----Original Message-----
From: linux-ia64-admin@linuxia64.org
[mailto:linux-ia64-admin@linuxia64.org]On Behalf Of David Mosberger
Sent: Tuesday, October 17, 2000 10:16 AM
To: Mattox, Dave
Cc: linux-ia64@linuxia64.org
Subject: Re: [Linux-ia64] Instruction Execution


>>>>> On Tue, 17 Oct 2000 09:51:51 -0700, "Mattox, Dave"
<DMattox@UNITECH.COM> said:

  Dave> I just got my Itanium Machine in and after installing Linux
  Dave> (no problems with that, good work guys), I tried some timings.

  Dave> I ran a loop 666,000,000 times and it appears that each bundle
  Dave> is taking 3 seconds to execute. So this means 3 cycles per
  Dave> bundle, or 1 cycle per instruction. Is the Lion SDV Machine
  Dave> executing instructions serially? If it is, is it Linux setting
  Dave> this, or are the beta chips disabled in some manner?

Make sure "Multidispersal" is enabled in the advanced chipset
configuration menu of the firmware (BIOS).

	--david

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