On Wed, Apr 10, 2024 at 05:23:18PM -0400, Peter Xu wrote: > On Wed, Apr 10, 2024 at 10:10:45PM +0100, Matthew Wilcox wrote: > > > I can do some tests later today or tomorrow. Any suggestion you have on > > > amplifying such effect that you have concern with? > > > > 8 socket NUMA system, 800MB text segment, 10,000 threads. No, I'm not > > joking, that's a real customer workload. > > Well, I believe you, but even with this, that's a total of 800MB memory on > a giant moster system... probably just to fault in once. > > And even before we talk about that into details.. we're talking about such > giant program running acorss hundreds of cores with hundreds of MB text, > then... hasn't the program developer already considered mlockall() at the > entry of the program? Wouldn't that greatly beneficial already with > whatever granule of locks that a future fault would take? I don't care what your theory is, or even what your benchmarking shows. I had basically the inverse of this patch, and my customer's workload showed significant improvement as a result. Data talks, bullshit walks. Your patch is NAKed and will remain NAKed.
