Messages in this thread | | | Date | Thu, 23 Feb 2012 16:50:05 +0530 | From | Srivatsa Vaddagiri <> | Subject | Re: sched: Avoid SMT siblings in select_idle_sibling() if possible |
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* Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> [2012-02-23 16:19:59]:
> > Enabling SD_BALANCE_WAKE used to be decidedly too expensive to consider. > > Maybe that has changed, but I doubt it. (general aside: testing with a > > bloated distro config is a big mistake) > > I am seeing 2.6% _improvement_ in volanomark score by enabling SD_BALANCE_WAKE > at SMT/MC domains.
Ditto with pipe benchmark.
> Machine : 2 Quad-core Intel X5570 CPU (H/T enabled) > Kernel : tip (HEAD at 6241cc8)
"perf bench sched pipe" was run 10 times and average ops/sec score alongwith std. dev is noted as below.
SD_BALANCE_WAKE SD_BALANCE_WAKE disabled enabled
Avg. score 108984.900 111844.300 (+2.6%) std dev 20383.457 21668.604
Note:
SD_BALANCE_WAKE for SMT/MC domain was enabled by writing into appropriate flags file present in /proc:
# cd /proc/sys/kernel/sched_domain/ # for i in `find . -name flags | grep domain1`; do echo 4671 > $i; done # for i in `find . -name flags | grep domain0`; do echo 703 > $i; done
- vatsa
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