Re: [Gems-users] CPU accesses to L2 cache

["Nauman Rafique" <nrafique@xxxxxxxxxx>]

I think by default, processor 0 handles all the interrupts. You can observe that by using 'mpstat' command. You can change that behavior by creating processor sets (google for how to do that).

But I would doubt if system calls and interrupt handling code will cause L1 misses and reach L2.

You can also check if the misses are supervisor misses or user misses.

 

--

Nauman

 

On 10/27/06, Dan Gibson <degibson@xxxxxxxx> wrote:

Are you sure that you're not merely observing that all other cpus
(cpu1-cpu7) are in the solaris idle loop?
cpu0 is probably active only to respond to your keypresses and to fork
your processes (ps -A, prstat, etc).

Also, did you issue instruction-fetch-mode instruction-fetch-trace,
istc-disable, dstc-disable to Simics?

Try running a mulitthreaded benchmark, and be sure to use
processor_bind() to get all the processors busy.

Regards,
Dan

Daniele Bordes wrote:

>Dear Gems Users, I tried to run some simple simulations using Simics + Ruby.
>The simulated machine is a 8-Sparc Processors with Solaris 9.
>L2-cache is a D-NUCA cache with 256 banks.
>I have noticed this fact (which seems to me strange) in ruby statistics:
>
>
>In Ruby statistics, CPU0 number of accesses on L2-cache is MUCH
>greater than other CPU's ones.
>
>The fact is that I have set Solaris fsflush mechanism frequency to be
>very very slow (by changing a parameter inside /etc/system and
>rebooting), and if I type "ps -A" from simulated machine, I see only
>this processes:
>
>sched
>init
>pageout
>fsflush
>sh
>ps
>
>
>And if I type "prstat" inside simulated machine, I see this:
>
>STATE     CPU    PROCESS
> cpu3       0.0%     prstat
> sleep      0.0%     sh
> sleep      0.0%     init
>
>
>So, in practice, the simulated machine seems to be "Idle", but there
>are many accesses of CPU0 to L2 cache.
>
>Since I am not a Solaris expert, does anybody know if this is correct?
>
>I am sorry to be a nuisance.
>Thank you very much.
>_______________________________________________
>Gems-users mailing list
>Gems-users@xxxxxxxxxxx
>https://lists.cs.wisc.edu/mailman/listinfo/gems-users
>Use Google to search the GEMS Users mailing list by adding "site: https://lists.cs.wisc.edu/archive/gems-users/" to your search.
>
>
>
>
_______________________________________________
Gems-users mailing list
Gems-users@xxxxxxxxxxx
https://lists.cs.wisc.edu/mailman/listinfo/gems-users
Use Google to search the GEMS Users mailing list by adding "site: https://lists.cs.wisc.edu/archive/gems-users/" to your search.