On (24/11/27 09:31), Barry Song wrote: > On Tue, Nov 26, 2024 at 11:53 PM Sergey Senozhatsky > <senozhatsky@xxxxxxxxxxxx> wrote: > > > > On (24/11/26 14:09), Sergey Senozhatsky wrote: > > > > swap-out time(ms) 68711 49908 > > > > swap-in time(ms) 30687 20685 > > > > compression ratio 20.49% 16.9% > > > > I'm also sort of curious if you'd use zstd with pre-trained user > > dictionary [1] (e.g. based on a dump of your swap-file under most > > common workloads) would it give you desired compression ratio > > improvements (on current zram, that does single page compression). > > > > [1] https://github.com/facebook/zstd?tab=readme-ov-file#the-case-for-small-data-compression > > Not yet, but it might be worth trying. A key difference between servers and > Android phones is that phones have millions of different applications > downloaded from the Google Play Store or other sources. Maybe yes maybe not, I don't know. It could be that that 99% of users use the same 1% apps out of those millions. > In this case, would using a dictionary be a feasible approach? Apologies > if my question seems too naive. It's a good question, and there is probably only one way to answer it - through experiments, it's data dependent, so it's case-by-case. > On the other hand, the advantage of a pre-trained user dictionary > doesn't outweigh the benefits of large block compression? Can’t both > be used together? Well, so far the approach has many unmeasured unknowns and corner cases, I don't think I personally even understand all of them to begin with. Not sure if I have a way to measure and analyze, that mTHP swapout seems like a relatively new thing and it also seems that you are still fixing some of its issues/shortcomings.
