On Tue, Jun 03, 2025 at 05:55:18PM +0200, Christian König wrote: > On 6/3/25 16:28, Christoph Hellwig wrote: > > On Tue, Jun 03, 2025 at 04:18:22PM +0200, Christian König wrote: > >>> Does it matter compared to the I/O in this case? > >> > >> It unfortunately does, see the numbers on patch 3 and 4. > > > > That's kinda weird. Why does the page table lookup tage so much > > time compared to normal I/O? > > I have absolutely no idea. It's rather surprising for me as well. > > The user seems to have a rather slow CPU paired with fast I/O, but it still looks rather fishy to me. > > Additional to that allocating memory through memfd_create() is *much* slower on that box than through dma-buf-heaps (which basically just uses GFP and an array). Can someone try to reproduce these results on a normal system before we're building infrastructure based on these numbers?
