[parsec-users] CPU Affinity

Yungang Bao ybao at CS.Princeton.EDU
Tue Sep 13 11:56:06 EDT 2011


Hi Abhisek,

According to the parsec_hooks man page, PARSEC_CPU_BASE indeicates the ID of the base CPU to use, which means that the workload will not use any CPUs below that ID. So when you set PARSEC_CPU_BASE=0, the workload may run on CPUs 4~15, since their IDs are greater than 0.  Maybe you can try set PARSEC_CPU_BASE = 12.

Best Regards,
Yungang

----- Original Message -----
From: abhisekpan at gmail.com
To: parsec-users at lists.cs.princeton.edu
Sent: Wednesday, September 7, 2011 10:22:57 AM
Subject: [parsec-users] CPU Affinity


Hi, 

I am trying to restrict the cores on which the benchmarks run, and I am doing the following: 

I am running parsec on simics on a 16 core simulated linux-amd64 system. When I am running canneal (say) with 4 threads, I am first setting the set affinity hook (it was enabled by default anyway). Then I am setting the environment variables PARSEC_CPU_NUM and PARSEC_CPU_BASE. The commands in the script are: 


eval_cli_line('con0.input("mkdir ~/phooks_run_small \n")') 
eval_cli_line('con0.input("cd parsec-2.1 \n")') 
eval_cli_line('con0.input("PARSEC_CPU_NUM=4 \n")') 
eval_cli_line('con0.input("PARSEC_CPU_BASE=0 \n")') 
eval_cli_line('con0.input("./bin/parsecmgmt -a run -p canneal -n 4 -i simsmall -c gcc-hooks -d ~/phooks_run_small\n")') 

So this would mean canneal runs on cores 0-3 ? But, when I track the binary through a tracker in simics, the program runs in other cores as well. 

Am I missing something? Any pointers would be highly appreciated! 

Thank you very much! 
-- 
Abhisek 
Live Long and Prosper 

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