On May 13 16:42, Christian Franke wrote: > Corinna Vinschen via Cygwin-apps wrote: > > When running a shell script, certain executables (especially coreutils, > > gawk, sed, grep, find) are not so very infrequently accessed. Is this > > compression really feasible for these binaries? Did you compare shell > > script performance with non-compressed, XPRESS16K and LZX compressed > > /bin dir? > > Good point. Now I did a test with a ./configure script run after reboot: > There was significant difference with /bin/*.exe (only) uncompressed, NTFS-, > XPRESS16K- or LZX-compressed. Time was always around 23s. > > Here a read speed test with fast and slow storage and a 10+ years old > i7-2600K (4C/8T). The 256MiB test file was generated by concatenating > various EXE files. All file accesses were the first after reboot. AV > (defender) was turned off: > > > Compression MiB T1 T2 T3,T4 > ====================================== > None 256 0.69s 10.1s <0.02s > NTFS 159 1.03s 8.1s <0.02s > XPRESS4K 138 - > XPRESS8K 128 - > XPRESS16K 123 0.64s 5.4s <0.02s > LZX 97 0.79s 4.8s <0.02s > > T1,T2: Read whole file: time dd if=FILE bs=FILESIZE of=/dev/null > T3,T4: Read last byte: time dd if=FILE bs=1 skip=FILESIZE-1 of=/dev/null > > T1,T3: SATA SSD, raw read speed with dd bs=1M: ~520MB/s > T2,T4: USB3 flash drive via USB2, raw read speed: ~27MB/s > > > As expected, compression helps to improve 'virtual' read speed on slow > storage. Otherwise, it depends on storage speed, CPU speed, system load, ... > As unexpected (for me), even LZX seems to be suitable for random reads which > are done when EXE files are preloaded or paged-in. > > If the files were already cached, all read times were similar: ~0.135s for > the whole file. > > For more flexibility, I will provide a new version of the patch with > '--compact-os ALGORITHM' option.
Great, thanks! Corinna
