From c5751c62074d8ed8ee260257bf89f6ac210e5ab9 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 15 Mar 2012 15:02:56 +0100 Subject: [PATCH] Document compress_buffer_percentage, compress_buffer_chunk Signed-off-by: Jens Axboe --- HOWTO | 16 ++++++++++++++++ fio.1 | 14 ++++++++++++++ 2 files changed, 30 insertions(+) diff --git a/HOWTO b/HOWTO index 30e40593..e4614ea8 100644 --- a/HOWTO +++ b/HOWTO @@ -488,6 +488,22 @@ scramble_buffers=bool If refill_buffers is too costly and the target is block compression attempts, but it will stop naive dedupe of blocks. Default: true. +buffer_compress_percentage=int If this is set, then fio will attempt to + provide IO buffer content (on WRITEs) that compress to + the specified level. Fio does this by providing a mix of + random data and zeroes. Note that this is per block size + unit, for file/disk wide compression level that matches + this setting, you'll also want to set refill_buffers. + +buffer_compress_chunk=int See buffer_compress_percentage. This + setting allows fio to manage how big the ranges of random + data and zeroed data is. Without this set, fio will + provide buffer_compress_percentage of blocksize random + data, followed by the remaining zeroed. With this set + to some chunk size smaller than the block size, fio can + alternate random and zeroed data throughout the IO + buffer. + nrfiles=int Number of files to use for this job. Defaults to 1. openfiles=int Number of files to keep open at the same time. Defaults to diff --git a/fio.1 b/fio.1 index f7abff89..c4c90b42 100644 --- a/fio.1 +++ b/fio.1 @@ -359,6 +359,20 @@ contents to defeat normal de-dupe attempts. This is not enough to defeat more clever block compression attempts, but it will stop naive dedupe of blocks. Default: true. .TP +.BI buffer_compress_percentage \fR=\fPint +If this is set, then fio will attempt to provide IO buffer content (on WRITEs) +that compress to the specified level. Fio does this by providing a mix of +random data and zeroes. Note that this is per block size unit, for file/disk +wide compression level that matches this setting, you'll also want to set +\fBrefill_buffers\fR. +.TP +.BI buffer_compress_chunk \fR=\fPint +See \fBbuffer_compress_percentage\fR. This setting allows fio to manage how +big the ranges of random data and zeroed data is. Without this set, fio will +provide \fBbuffer_compress_percentage\fR of blocksize random data, followed by +the remaining zeroed. With this set to some chunk size smaller than the block +size, fio can alternate random and zeroed data throughout the IO buffer. +.TP .BI nrfiles \fR=\fPint Number of files to use for this job. Default: 1. .TP -- 2.25.1