i#6938 sched migrate: Add observed migrations to schedule stats #7057
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While the schedule_stats tool already reports the migration count from the scheduler, that is only non-zero for a dynamic schedule, resulting in 0 for core-sharded-on-disk traces. We add "observed migrations" where schedule_stats looks for migrations on its own. This requires a global lock on each context switch, but experimental results show that this does not seem to cause noticeable overhead. Adds some testing. Issue: #6938
brettcoon
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Oct 25, 2024
derekbruening
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Oct 28, 2024
Fixes an assert on the new observed_migrations stat added to schedule_stats in PR #7057. These observed_migrations are counted on the destination core, while the scheduler reports migrations away from a source core: so they can differ, causing the assert to fire. Fixed by moving it to only check the aggregated stats across all cores. Tested on the internal trace where the assert fired before. Issue: #6938
derekbruening
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Oct 29, 2024
Fixes an assert on the new observed_migrations stat added to schedule_stats in PR #7057. These observed_migrations are counted on the destination core, while the scheduler reports migrations away from a source core: so they can differ, causing the assert to fire. Fixed by moving it to only check the aggregated stats across all cores. Tested on the internal trace where the assert fired before. Issue: #6938
derekbruening
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Oct 29, 2024
schedule_stats_t::get_total_counts() was not including scheduler-provided stats, as it was doing its own simple aggregation instead of calling aggregate_results(). We fix that here. That then triggers the newly added assert from PR #7057 which checks for the scheduler-provided value being exactly equal meaning there is no data available. It fires on the schedule_stats_test, which uses a mock stream which returns -1 for such a stat, so we end up with a negative value. We update the assert for that condition. Issue: #6938
derekbruening
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Oct 29, 2024
…7060) schedule_stats_t::get_total_counts() was not including scheduler-provided stats, as it was doing its own simple aggregation instead of calling aggregate_results(). We fix that here. That then triggers the newly added assert from PR #7057 which checks for the scheduler-provided value being exactly equal meaning there is no data available. It fires on the schedule_stats_test, which uses a mock stream which returns -1 for such a stat, so we end up with a negative value. We update the assert for that condition. Issue: #6938
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While the schedule_stats tool already reports the migration count from the scheduler, that is only non-zero for a dynamic schedule, resulting in 0 for core-sharded-on-disk traces. We add "observed migrations" where schedule_stats looks for migrations on its own. This requires a global lock on each context switch, but experimental results show that this does not seem to cause noticeable overhead.
Adds some testing.
Issue: #6938