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authorMichael Neuling <mikey@neuling.org>2010-06-08 14:57:02 +1000
committerIngo Molnar <mingo@elte.hu>2010-06-09 10:34:55 +0200
commit532cb4c401e225b084c14d6bd6a2f8ee561de2f1 (patch)
tree0ce57c2e21cd12ee05561ab2b9c4b66729da8e5a /include/linux/topology.h
parent9d5efe05eb0c904545a28b19c18b949f23334de0 (diff)
sched: Add asymmetric group packing option for sibling domain
Check to see if the group is packed in a sched doman. This is primarily intended to used at the sibling level. Some cores like POWER7 prefer to use lower numbered SMT threads. In the case of POWER7, it can move to lower SMT modes only when higher threads are idle. When in lower SMT modes, the threads will perform better since they share less core resources. Hence when we have idle threads, we want them to be the higher ones. This adds a hook into f_b_g() called check_asym_packing() to check the packing. This packing function is run on idle threads. It checks to see if the busiest CPU in this domain (core in the P7 case) has a higher CPU number than what where the packing function is being run on. If it is, calculate the imbalance and return the higher busier thread as the busiest group to f_b_g(). Here we are assuming a lower CPU number will be equivalent to a lower SMT thread number. It also creates a new SD_ASYM_PACKING flag to enable this feature at any scheduler domain level. It also creates an arch hook to enable this feature at the sibling level. The default function doesn't enable this feature. Based heavily on patch from Peter Zijlstra. Fixes from Srivatsa Vaddagiri. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <20100608045702.2936CCC897@localhost.localdomain> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/linux/topology.h')
-rw-r--r--include/linux/topology.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/topology.h b/include/linux/topology.h
index c44df50a05ab..cf57f30d0dcb 100644
--- a/include/linux/topology.h
+++ b/include/linux/topology.h
@@ -103,6 +103,7 @@ int arch_update_cpu_topology(void);
| 1*SD_SHARE_PKG_RESOURCES \
| 0*SD_SERIALIZE \
| 0*SD_PREFER_SIBLING \
+ | arch_sd_sibiling_asym_packing() \
, \
.last_balance = jiffies, \
.balance_interval = 1, \