On Thu, Aug 22, 2024 at 1:31 AM Shakeel Butt <shakeel.butt@xxxxxxxxx> wrote: > > On Wed, Aug 21, 2024 at 03:45:40PM GMT, hanchuanhua@xxxxxxxx wrote: > > From: Chuanhua Han <hanchuanhua@xxxxxxxx> > > > > > > 3. With both mTHP swap-out and swap-in supported, we offer the option to enable > > zsmalloc compression/decompression with larger granularity[2]. The upcoming > > optimization in zsmalloc will significantly increase swap speed and improve > > compression efficiency. Tested by running 100 iterations of swapping 100MiB > > of anon memory, the swap speed improved dramatically: > > time consumption of swapin(ms) time consumption of swapout(ms) > > lz4 4k 45274 90540 > > lz4 64k 22942 55667 > > zstdn 4k 85035 186585 > > zstdn 64k 46558 118533 > > Are the above number with the patch series at [2] or without? Also can > you explain your experiment setup or how can someone reproduce these? Hi Shakeel, The data was recorded after applying both this patch (swap-in mTHP) and patch [2] (compressing/decompressing mTHP instead of page). However, without the swap-in series, patch [2] becomes useless because: If we have a large object, such as 16 pages in zsmalloc: do_swap_page will happen 16 times: 1. decompress the whole large object and copy one page; 2. decompress the whole large object and copy one page; 3. decompress the whole large object and copy one page; .... 16. decompress the whole large object and copy one page; So, patchset [2] will actually degrade performance rather than enhance it if we don't have this swap-in series. This swap-in series is a prerequisite for the zsmalloc/zram series. We reproduced the data through the following simple steps: 1. Collected anonymous pages from a running phone and saved them to a file. 2. Used a small program to open and read the file into a mapped anonymous memory. 3. Do the belows in the small program: swapout_start_time madv_pageout() swapout_end_time swapin_start_time read_data() swapin_end_time We calculate the throughput of swapout and swapin using the difference between end_time and start_time. Additionally, we record the memory usage of zram after the swapout is complete. > > > [2] https://lore.kernel.org/all/20240327214816.31191-1-21cnbao@xxxxxxxxx/ > Thanks Barry
