From 2e33c812e8b1bea563893f17ff5edcb7023d5d41 Mon Sep 17 00:00:00 2001 From: the8472 Date: Fri, 22 Jul 2022 22:18:07 +0200 Subject: [PATCH] [review] mention that runtime may scale with # of mountpoints Co-authored-by: Josh Triplett --- library/std/src/thread/mod.rs | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/library/std/src/thread/mod.rs b/library/std/src/thread/mod.rs index f02a7de04e5be..add93b618a6dc 100644 --- a/library/std/src/thread/mod.rs +++ b/library/std/src/thread/mod.rs @@ -1575,6 +1575,11 @@ fn _assert_sync_and_send() { /// queried, e.g. due to sandboxing. /// - It may undercount the amount of parallelism if the current thread's affinity mask /// does not reflect the process' cpuset, e.g. due to pinned threads. +/// - If the process is in a cgroup v1 cpu controller, this may need to +/// scan mountpoints to find the corresponding cgroup v1 controller, +/// which may take time on systems with large numbers of mountpoints. +/// (This does not apply to cgroup v2, or to processes not in a +/// cgroup.) /// /// On all targets: /// - It may overcount the amount of parallelism available when running in a VM