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. Since they both use the default preset now, that is what I'm comparing. It *is* likely that it should be changed, but that should happen in a separate patch anyway.
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