Re: [RFC PATCH v6] sched: Fix performance regression introduced by mm_cid

From: Aaron Lu
Date: Fri Apr 14 2023 - 05:43:35 EST


On Thu, Apr 13, 2023 at 06:33:56PM -0400, Mathieu Desnoyers wrote:
> Introduce per-mm/cpu current concurrency id (mm_cid) to fix a PostgreSQL
> sysbench regression reported by Aaron Lu.

No lock contention from cid.

For postgres_sysbench:
mm_cid_get() is in the range of 0.2% - 1.2% during a 5 minutes run.
Other cid functions are pretty minor.

For hackbench:
mm_cid_get() is in the range of 2.x% - 7.x%. Other cid functions are
pretty minor.