Re: Performance drop due to alloc_workqueue() misuse and recent change

2023-12-19 Thread Tejun Heo
Hello, again. On Mon, Dec 04, 2023 at 04:03:47PM +, Naohiro Aota wrote: ... > In summary, we misuse max_active, considering it is a global limit. And, > the recent commit introduced a huge performance drop in some cases. We > need to review alloc_workqueue() usage to check if its max_active

Performance drop due to alloc_workqueue() misuse and recent change

2023-12-04 Thread Naohiro Aota
Recently, commit 636b927eba5b ("workqueue: Make unbound workqueues to use per-cpu pool_workqueues") changed WQ_UNBOUND workqueue's behavior. It changed the meaning of alloc_workqueue()'s max_active from an upper limit imposed per NUMA node to a limit per CPU. As a result, massive number of workers

Re: Performance drop due to alloc_workqueue() misuse and recent change

2023-12-04 Thread Tejun Heo
Hello, On Mon, Dec 04, 2023 at 04:03:47PM +, Naohiro Aota wrote: > Recently, commit 636b927eba5b ("workqueue: Make unbound workqueues to use > per-cpu pool_workqueues") changed WQ_UNBOUND workqueue's behavior. It > changed the meaning of alloc_workqueue()'s max_active from an upper limit >