Level 5 isn’t crazy, though it’s still some 70% slower than level 1. zlib.compressobj(level=1) time=7.6 size=84869397 zlib.compressobj(level=2) time=7.8 size=82465461 zlib.compressobj(level=3) time=8.4 size=79576183 zlib.compressobj(level=4) time=12.2 size=74672475 zlib.compressobj(level=5) time=13.2 size=72642875 zlib.compressobj(level=6) time=15.7 size=69988031 zlib.compressobj(level=7) time=17.9 size=69281853 zlib.compressobj(level=8) time=30.4 size=68666299 zlib.compressobj(level=9) time=59.0 size=68326007
bz2.BZ2Compressor(compresslevel=1) time=30.6 size=61319073 bz2.BZ2Compressor(compresslevel=9) time=40.0 size=54246781 lz4.compress time=2.4 size=108683033 Sizes are after base64 encoding. (If you’re worried about upload size, why not recompress the report at upload time, when it’s not going to take the user by surprise?) -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to apport in Ubuntu. https://bugs.launchpad.net/bugs/1537635 Title: Reduce zlib compression level for massive performance increase Status in Apport: New Status in apport package in Ubuntu: Confirmed Bug description: When apport takes a core dump of a large application, it uses 100% CPU for a _long_ time (often 30 seconds or more) to compress the core dump. The system is virtually unusable during this time, especially if the application was the window manager and won’t be restarted until the core dump is complete. This is a longstanding known problem; it motivated the switch from bzip2 to zlib level 9 back in apport 0.24. That made it much better, but it’s still quite bad. So why not switch from zlib level 9 to zlib level 1? I tested this on a core dump of gnome-shell, and while it increased the size of the .crash file by 24% (68.5 MB to 85.0 MB), it decreased the needed CPU time by a FACTOR OF EIGHT (58.6 seconds to 7.3 seconds). This tradeoff seems more than worthwhile for this use case. To manage notifications about this bug go to: https://bugs.launchpad.net/apport/+bug/1537635/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
