A Fresh Take On Speculative Page Faulting Aims For The Mainline Kernel

[phoronix]

Phoronix: A Fresh Take On Speculative Page Faulting Aims For The Mainline Kernel

Over the years there have been a number of rounds of patches published for speculative page faulting. The goal has been to support user-space page-faults without holding the memory management semaphores and to ultimately allow for better performance especially with threaded workloads. A fresh take on the speculative page faulting (SPF) functionality was recently volleyed on the kernel mailing list...

https://www.phoronix.com/scan.php?page=news_item&px=Spec-Page-Faulting-2021

[ms178]

I've just tried his 5.12.0-sfp github branch but compilation with Clang fails with:

mm/memory.c:3724:3: error: implicit declaration of function 'lru_cache_add_inactive_or_unevictable' [-Werror,-Wimplicit-function-declaration]
lru_cache_add_inactive_or_unevictable(page, vma);
^

[edit:] Hm, that was with the Multigenerational-LRU-patchset on top of that, without it I cannot reproduce the issue.

[ms178]

Some observations after trying it out for a day. The patchset unfortunately won't apply cleanly on the latest Xanmod sources (as that also contains the Multigenerational-LRU-patches which don't go together well with these patches). I'd recommend to try the 5.12.0-spf-anon branch, the lesser tested spf-branch cased sound issues for me. I very like that my programs start faster, the first Chrome load after a reboot is cut in half on my SSHD-RAID-0-array. Also my Steam games launched faster, hence I very much welcome the results for normal desktop usage (my desktop is already latency-optimized, but the improvement is still noticeable).