On Mon, Jul 7, 2014 at 10:33 PM, Zbigniew Jędrzejewski-Szmek <[email protected]> wrote: > On Mon, Jul 07, 2014 at 09:47:15PM +0200, Kay Sievers wrote: >> On Mon, Jul 7, 2014 at 9:40 PM, Zbigniew Jędrzejewski-Szmek >> <[email protected]> wrote: >> > On Mon, Jul 07, 2014 at 09:35:06PM +0300, Uoti Urpala wrote: >> >> On Sat, 2014-07-05 at 20:56 +0200, Zbigniew Jędrzejewski-Szmek wrote: >> >> > This is useful to test the behaviour of the compressor for various >> >> > buffer >> >> > sizes. >> >> > >> >> > Time is limited to a minute per compression, since otherwise, when LZ4 >> >> > takes more than a second which is necessary to reduce the noise, XZ >> >> > takes more than 10 minutes. >> >> > >> >> > % build/test-compress-benchmark (without time limit) >> >> > XZ: compressed & decompressed 2535300963 bytes in 794.57s (3.04MiB/s), >> >> > mean compresion 99.95%, skipped 3570 bytes >> >> > LZ4: compressed & decompressed 2535303543 bytes in 1.56s >> >> > (1550.07MiB/s), mean compresion 99.60%, skipped 990 bytes >> >> >> >> Like your earlier comparison, this compares the wrong thing. If >> >> compression speed matters more than best compression ratio, you >> >> shouldn't use the default settings for xz. If you want to compare with >> >> LZ4, this benchmark should at least compare the equivalent of "xz -0". >> >> > The comparison should be done for whatever setting is used in journald >> > and/or coredump. >> >> No, The current defaults are irrelevant. >> >> The comparison should be done with values that indicate that >> introducing a new compression algorithm is needed. If xz *can* be >> instructed to reach acceptable results, we would better stick with it. > With preset=default (6): > XZ: compressed & decompressed 220536103 bytes in 60.03s (3.50MiB/s), ... > > With 0: > XZ: compressed & decompressed 2535300963 bytes in 33.01s (73.25MiB/s), ... > > LZ4: compressed & decompressed 2535303543 bytes in 1.31s (1838.75MiB/s), ...
Interesting numbers. Thanks for providing them. Kay _______________________________________________ systemd-devel mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/systemd-devel
