Messages in this thread | | | Date | Fri, 02 Apr 2004 17:18:44 +1000 | From | Nick Piggin <> | Subject | Scheduler balancing statistics |
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Hi, I have been adapting Rick's schedstats package to extract more information from the sched-domains infrastructure.
Before I release a patch, I'd like some input as to what statistics people want covered, and in what form they would like them presented (I'm talking only about balancing).
I have covered the basic stuff I could think of, and written a small C program to parse it (I'm no good at perl) and output this (sorry it is still pretty ugly):
npiggin@didi:~/usr/src/linux-2.4$ stats7 pre post For domain0 31.005358l load balance calls / s move 1.162474l tasks / s Of which, 66.198008l% calls and 67.187500l% task moves from idle balancing 93.539823l% found no imbalance 2.654867l% found an imbalance but failed 30.232558l% of tasks were moved with cache nice Of which, 25.834798l% calls and 28.125000l% task moves from busy balancing 95.918367l% found no imbalance 0.000000l% found an imbalance but failed 100.000000l% of tasks were moved with cache nice Of which, 7.967194l% calls and 4.687500l% task moves from newidle balancing 94.117647l% found no imbalance 0.000000l% found an imbalance but failed 100.000000l% of tasks were moved with cache nice 0.000000l active balances / s move 0.000000l tasks / s 0.036327l passive load balances / s 2.070657l affine wakeups / s 0.000000l exec balances / s
This was the behaviour during a make -j4 bzImage on a 2xSMP. For a NUMA system, it would also give you domain1 for example.
A few interesting things this tells us: load_balance is being called 31 times per second, ~95% of the time there is no imbalance, and it moves 1.16 tasks per second.
idle balancing is going over the cache_nice_tries limit 70% of the time which might warrant cache_nice_tries being increased.
etc.
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