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. Kay _______________________________________________ systemd-devel mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/systemd-devel
