On Wednesday 21 April 2010, Jiri Slaby wrote: > On 03/31/2010 10:29 PM, Rafael J. Wysocki wrote: > > On Wednesday 31 March 2010, Jiri Slaby wrote: > >> On 03/30/2010 10:50 PM, Rafael J. Wysocki wrote: > >>> So, I definitely would like to see numbers. > >> > >> With the patch attached, I get similar results for > >> uncompressed image -> user.c -> s2disk (compress+threads) > >> compressed image -> user.c -> s2disk (none of compress+threads) > >> > >> BUT note that there are differences in pages _copied_ in the "user.c -> > >> s2disk" phase. Compression was about 40 %. So in the former case 100000 > >> pages went through and in the latter one only ~ 38000. So presumably > >> there will be savings if the pages are compressed in the kernel in the > >> save-image phase instead of in userspace. > >> > >> I'll test (after I hack that up) also the case of image compression when > >> saving the image and let you know. > >> > >> It was tested on a machine with openSUSE factory with init 5 with KDE 4. > >> The memory consumption was ~ 400M (100000 pages) after boot every time. > >> Hibernation lasted 12-13s in both cases. > > > > So that's pretty much the same and I don't think feeding compressed images to > > s2disk is not worth the effort. Let's assume s2disk will always receive a raw > > image (that will make it backwards compatible too). > > Hi. > > Yes, I did it solely for comparison purposes. > > Now, with the patch attached (depending on either COMPRESS_IMAGE or > COMPRESS_IMAGE1 defined) I tried to compare compression while doing > atomic copy with compression done when image storage takes place. The > latter outperformed the former a bit. I did 8 measurements with the > setup same as above. The average for them is 9684.32 and 10855.07 stored > raw (uncompressed) pages per second. That is 4.5M/s more. > > There is a sheet with the numbers at: > http://spreadsheets.google.com/ccc?key=0AvVn7xYA1DnodHFFYzg3Y2tpMUl5NFlURXRtR0xQdmc&hl=en Thanks for doing that work! So clearly from performance POV it is better to compress while saving. Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
