Re: [Gems-users] Change in cpu frequency - question


Date: Sun, 7 Feb 2010 14:15:48 -0600
From: Dan Gibson <degibson@xxxxxxxx>
Subject: Re: [Gems-users] Change in cpu frequency - question
As I recall, %stick and %stick_cmpr are sun-specific additions to v9:

For this kind of thing, I usually go to the UltraSPARC-III manual:
From www.sun.com/processors/manuals/USIIIv2.pdf:

[quote]
When the STICK_COMPARE.INT_DIS bit is zero (system tick compare is enabled) a nd
its STICK_CMPR field matches the value in the STICK register, then the SM field in
SOFTINT is set to one and a Level-14 interrupt is generated. See Section 6.7.4, “Timer
State Registers: ASRs 4, 23, 24, 25” for details.
[/quote]

In other words, %stick is the system tick register. %stick_cmpr is its suicide count.

Regards,
Dan

On Sun, Feb 7, 2010 at 2:05 PM, Pradeep Ramachandran <pramach2@xxxxxxxx> wrote:

On Feb 6, 2010, at 7:00 PM, Philip Garcia wrote:

You can get around the 75MHz clock issue by stalling the timer interrupts  until you want them.  This can be done by manipulating the tick and tick compare register so that it goes off at specified times.


I have been digging around to find information on the tick and tick compare registers (%stick and %stick_cmpr), but I have found hardly any info (even the SPARCV9 manual doesn't list them!). Do you have any pointers on how the registers are used? As I'd mentioned before, I would like to make the timer interrupts less frequent so that I simulate a 2GHz-like balanced machine with the 75MHz simics system, for which I need to make timer interrupts far less frequent.

Thanks,

Pradeep.
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