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author | Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> | 2013-10-30 08:42:42 +0530 |
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committer | Ingo Molnar <mingo@kernel.org> | 2013-11-06 12:37:54 +0100 |
commit | 2042abe7977222ef606306faa2dce8fd51e98e65 (patch) | |
tree | 5f4c647b97c6dae097fd8b6e05cf34c4fb3db7fd /security | |
parent | b8a216269ec0ce2e961d32e6d640d7010b8a818e (diff) | |
download | blackbird-op-linux-2042abe7977222ef606306faa2dce8fd51e98e65.tar.gz blackbird-op-linux-2042abe7977222ef606306faa2dce8fd51e98e65.zip |
sched: Fix asymmetric scheduling for POWER7
Asymmetric scheduling within a core is a scheduler loadbalancing
feature that is triggered when SD_ASYM_PACKING flag is set. The goal
for the load balancer is to move tasks to lower order idle SMT threads
within a core on a POWER7 system.
In nohz_kick_needed(), we intend to check if our sched domain (core)
is completely busy or we have idle cpu.
The following check for SD_ASYM_PACKING:
(cpumask_first_and(nohz.idle_cpus_mask, sched_domain_span(sd)) < cpu)
already covers the case of checking if the domain has an idle cpu,
because cpumask_first_and() will not yield any set bits if this domain
has no idle cpu.
Hence, nr_busy check against group weight can be removed.
Reported-by: Michael Neuling <michael.neuling@au1.ibm.com>
Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Tested-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: vincent.guittot@linaro.org
Cc: bitbucket@online.de
Cc: benh@kernel.crashing.org
Cc: anton@samba.org
Cc: Morten.Rasmussen@arm.com
Cc: pjt@google.com
Link: http://lkml.kernel.org/r/20131030031242.23426.13019.stgit@preeti.in.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'security')
0 files changed, 0 insertions, 0 deletions