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