Fio 2.1

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index 7dc7d4827e340dba61c3d67e53e78c1d83a973aa..b1dcd296d700abbb14a2c50d7146c5668aa686ba 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -766,6 +766,17 @@ random_distribution=str:float      By default, fio will use a completely uniform
                random_distribution=zipf:1.2 as the option. If a non-uniform
                model is used, fio will disable use of the random map.
 
+percentage_random=int  For a random workload, set how big a percentage should
+               be random. This defaults to 100%, in which case the workload
+               is fully random. It can be set from anywhere from 0 to 100.
+               Setting it to 0 would make the workload fully sequential. Any
+               setting in between will result in a random mix of sequential
+               and random IO, at the given percentages.
+       
+percentage_sequential=int      See percentage_random. It is guaranteed that
+               they add up to 100. The later setting has priority, each
+               will adjust the other.
+
 norandommap    Normally fio will cover every block of the file when doing
                random IO. If this option is given, fio will just get a
                new random offset without looking at past io history. This
@@ -1219,7 +1230,7 @@ write_lat_log=str Same as write_bw_log, except that this option stores io
 
                write_lat_log=foo
 
-               The actual log names will be foo_slat.log, foo_slat.log,
+               The actual log names will be foo_slat.log, foo_clat.log,
                and foo_lat.log. This helps fio_generate_plot fine the logs
                automatically.
 
@@ -1241,6 +1252,7 @@ log_avg_msec=int By default, fio will log an entry in the iops, latency,
 lockmem=int    Pin down the specified amount of memory with mlock(2). Can
                potentially be used instead of removing memory or booting
                with less memory to simulate a smaller amount of memory.
+               The amount specified is per worker.
 
 exec_prerun=str        Before running this job, issue the command specified
                through system(3).
@@ -1599,6 +1611,9 @@ util=             The disk utilization. A value of 100% means we kept the disk
 
 It is also possible to get fio to dump the current output while it is
 running, without terminating the job. To do that, send fio the USR1 signal.
+You can also get regularly timed dumps by using the --status-interval
+parameter, or by creating a file in /tmp named fio-dump-status. If fio
+sees this file, it will unlink it and dump the current output status.
 
 
 7.0 Terse output
@@ -1720,7 +1735,7 @@ trim       trim the given file from the given 'offset' for 'length' bytes
 
 
 9.0 CPU idleness profiling
-
+--------------------------
 In some cases, we want to understand CPU overhead in a test. For example,
 we test patches for the specific goodness of whether they reduce CPU usage.
 fio implements a balloon approach to create a thread per CPU that runs at