Messages in this thread Patch in this message | | | From | Vaidyanathan Srinivasan <> | Subject | [RFC PATCH v2 4/5] sched: small imbalance corrections | Date | Thu, 09 Oct 2008 17:39:51 +0530 |
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Add functions to bump up the imbalance to eventually initiate a task move to balance across groups.
Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> ---
kernel/sched.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 74 insertions(+), 0 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c index c99b5bd..cf1aae1 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -3229,6 +3229,80 @@ void update_sd_loads(struct sd_loads *sdl, struct group_loads *gl) } } +/* Bump up imbalance to one task so that some task movement can happen */ + +int small_imbalance_one_task(struct sd_loads *sdl, unsigned long *imbalance) +{ + unsigned int imbn; + imbn = 2; + if (sdl->local.nr_running) { + if (sdl->busiest.avg_load_per_task > + sdl->local.avg_load_per_task) + imbn = 1; + } + + if (sdl->busiest.load_per_cpu - sdl->local.load_per_cpu + + 2*sdl->busiest.avg_load_per_task >= + sdl->busiest.avg_load_per_task * imbn) { + *imbalance = sdl->busiest.avg_load_per_task; + return 1; + } + return 0; +} + +/* + * Adjust imbalance to move task if the result of the move will + * yield better use of cpu power + */ + +void small_imbalance_optimize_cpu_power(struct sd_loads *sdl, + unsigned long *imbalance) +{ + unsigned long tmp, pwr_now, pwr_move; + pwr_move = pwr_now = 0; + + /* + * OK, we don't have enough imbalance to justify moving tasks, + * however we may be able to increase total CPU power used by + * moving them. + */ + + pwr_now += sdl->busiest.group->__cpu_power * + min(sdl->busiest.avg_load_per_task, + sdl->busiest.load_per_cpu); + pwr_now += sdl->local.group->__cpu_power * + min(sdl->local.avg_load_per_task, + sdl->local.load_per_cpu); + pwr_now /= SCHED_LOAD_SCALE; + + /* Amount of load we'd subtract */ + tmp = sg_div_cpu_power(sdl->busiest.group, + sdl->busiest.avg_load_per_task * SCHED_LOAD_SCALE); + if (sdl->busiest.load_per_cpu > tmp) + pwr_move += sdl->busiest.group->__cpu_power * + min(sdl->busiest.avg_load_per_task, + sdl->busiest.load_per_cpu - tmp); + + /* Amount of load we'd add */ + if (sdl->busiest.load_per_cpu * sdl->busiest.group->__cpu_power < + sdl->busiest.avg_load_per_task * SCHED_LOAD_SCALE) + tmp = sg_div_cpu_power(sdl->local.group, + sdl->busiest.load_per_cpu * + sdl->busiest.group->__cpu_power); + else + tmp = sg_div_cpu_power(sdl->local.group, + sdl->busiest.avg_load_per_task * SCHED_LOAD_SCALE); + pwr_move += sdl->local.group->__cpu_power * + min(sdl->local.avg_load_per_task, + sdl->local.load + tmp); + pwr_move /= SCHED_LOAD_SCALE; + + /* Move if we gain throughput */ + if (pwr_move > pwr_now) + *imbalance = sdl->busiest.avg_load_per_task; + +} + #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) void update_powersavings_group_loads(struct sd_loads *sdl, struct group_loads *gl,
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