On 2/18/21 4:16 PM, Andrew Morton wrote: > On Thu, 18 Feb 2021 14:36:31 -0700 Jens Axboe <ax...@kernel.dk> wrote: > >> Currently we cap the batch count at max(32, 2*nr_online_cpus), which these >> days is kind of silly as systems have gotten much bigger than in 2009 when >> this heuristic was introduced. >> >> Bump it to capping it at 256 instead. This has a noticeable improvement >> for certain io_uring workloads, as io_uring tracks per-task inflight count >> using percpu counters. >> > > It will also make percpu_counter_read() and > percpu_counter_read_positive() more inaccurate than at present. Any > effects from this will take a while to discover.
It will, but the value of 32 is very low, especially when you are potentially doing millions of these per second. So I do think it should track the times a bit. > But yes, worth trying - I'll add it to the post-rc1 pile. Thanks! -- Jens Axboe
