On 04/24/23 at 11:22am, Lorenzo Stoakes wrote: > On Mon, Apr 24, 2023 at 12:08:22PM +0200, Uladzislau Rezki wrote: > > On Mon, Apr 24, 2023 at 10:55:20AM +0200, Michal Hocko wrote: > > > On Mon 24-04-23 09:44:00, Uladzislau Rezki wrote: > > > > On Fri, Apr 21, 2023 at 02:03:43PM +0200, Michal Hocko wrote: > > > > > On Tue 28-02-23 17:42:43, Uladzislau Rezki wrote: > > > > > > Hello, LSF. > > > > > > > > > > > > Title: Introduce a per-cpu-vmap-cache to eliminate a vmap lock contention > > > > > > > > > > > > Description: > > > > > > Currently the vmap code is not scaled to number of CPU cores in a system > > > > > > because a global vmap space is protected by a single spinlock. Such approach > > > > > > has a clear bottleneck if many CPUs simultaneously access to one resource. > > > > > > > > > > > > In this talk i would like to describe a drawback, show some data related > > > > > > to contentions and places where those occur in a code. Apart of that i > > > > > > would like to share ideas how to eliminate it providing a few approaches > > > > > > and compare them. > > > > > > > > > > It's been some time since you brough this up. Has there been any > > > > > progress on the topic? Do you still find it important to discuss it at > > > > > LSFMM? > > > > > > > > > The idea about sequence was/is: > > > > > > > > 1) Give an overview on the proposal; > > > > 2) Submit patches to address the problem; > > > > 3) Start a discussion over lkml with people who are interested in it; > > > > 4) Send out a complete solution. > > > > > > Thanks for the clarification. The usual LSFMM format is strongly > > > discussion focused. Long presentations are usually discouraged and they > > > should only introduce people to the underlying problem to kick of a > > > discussion. > > > > > I have not posted yet any RFC and have not kicked it yet. Though people > > are aware the problem. > > > > > > > > That being said, IMO it would be helpful to have some material on the > > > mailing list before any discussion could be productive. > > > > > This is what i have so far: > > > > wget ftp://vps418301.ovh.net/incoming/Fix_a_vmalloc_lock_contention_in_SMP_env.pdf > > > > I can, of course, move it forward over lkml only. If you are fully > > booked or there other reason then please just withdraw my proposal > > from your conference. > > For what it's worth I'm definitely interested in attending this session if > it goes ahead. I am sure Baoquan, if he's attending LSF/MM, would be too! (cc'd). Thanks for CC. Yes, I am very interested in this topic, have read it from the beginning. Unfortunately, I can't attend LSF/MM this year because of some reasons. I look forward to learning the decision or conclusion of the sessin, and reviewing Uladzislau's RFC or formal patchset later. Wish the session a great success, and you guys a pleasant meeting and discussion. Thanks Baoquan
