On Thu, Dec 7, 2023 at 4:42 PM Nhat Pham <nphamcs@xxxxxxxxx> wrote: > [..] > > I don't have any concrete numbers though - any numbers I can pull out > are from highly artificial tasks that only serve to test the > correctness aspect of the implementation. zswap.writeback disablement > would of course be faster in these situations (up to 33%!!!!) - but > that's basically just saying HDD is slow. Which is not very > informative or surprising, so I did not include it in the changelog. For instance, on a server with HDD, I allocate memories and populate them with random values (so that zswap store will always fail), and specify memory.high low enough to trigger reclaim. The time it takes to allocate the memories and just read through it a couple of times (doing silly things like computing the values' average etc.): zswap.writeback disabled: real 0m30.537s user 0m23.687s sys 0m6.637s 0 pages swapped in 0 pages swapped out zswap.writeback enabled: real 0m45.061s user 0m24.310s sys 0m8.892s 712686 pages swapped in 461093 pages swapped out (the last two lines are from vmstat -s).
