Messages in this thread | | | From | Jason Low <> | Subject | [PATCH v4 0/3] sched: Limiting idle balance | Date | Thu, 29 Aug 2013 13:05:33 -0700 |
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These patches modify and add to the way we limit idle balancing. The first patch reduces the chance we overestimate the avg_idle guestimator. The second patch makes idle balance compare the avg_idle with the max cost we ever spend on a new idle load balance per sched domain to limit idle balance.
The third is an RFC patch which periodically decays each domain's max newidle balance costs and compares avg_idle sd with max newidle balance + sched_migration_cost to determine if we should skip balancing.
These changes further reduce the chance we attempt idle balancing when the time a CPU remains idle is short and is not more than the cost to do the balancing.
The first 2 patches provide good performance boosts of many AIM7 workloads on an 8 socket (80 core) machine. The table below compares the average jobs per minute at 10-100, 200-1000, and 1100-2000 users between the vanilla 3.11-rc7 kernel and the 3.11-rc7 kernel with the first 2 patches with Hyperthreading enabled.
---------------------------------------------------------------- workload | % improvement | % improvement | % improvement | with patch | with patch | with patch | 1100-2000 users | 200-1000 users | 10-100 users ---------------------------------------------------------------- alltests | +12.2% | +7.5% | +1.0% ---------------------------------------------------------------- compute | -0.6% | -0.8% | +0.1% ---------------------------------------------------------------- custom | +24.0% | +25.03 | +16.4% ---------------------------------------------------------------- disk | +11.6% | +21.3% | +0.1% ---------------------------------------------------------------- fserver | +74.7% | +34.7% | -2.7% ---------------------------------------------------------------- high_systime | +21.2% | +10.5% | +0.6% ---------------------------------------------------------------- new_fserver | +59.8% | +23.7% | -1.2% ---------------------------------------------------------------- shared | +9.0% | +13.0% | +6.5% ----------------------------------------------------------------
Jason Low (3): sched: Reduce overestimating rq->avg_idle sched: Consider max cost of idle balance per sched domain sched: Periodically decay max cost of idle balance
arch/metag/include/asm/topology.h | 2 + include/linux/sched.h | 4 +++ include/linux/topology.h | 6 ++++ kernel/sched/core.c | 10 ++++--- kernel/sched/fair.c | 48 ++++++++++++++++++++++++++++++++++++- kernel/sched/sched.h | 3 ++ 6 files changed, 68 insertions(+), 5 deletions(-)
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