Add option for refilling IO buffers on each submit

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index 66ebebe8579dd5954e574bf016c31b5fbd0e5baf..36e42aaf6b9defb210d83d0b538284bea7f6a4d6 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -336,6 +336,11 @@ bs_unaligned       If this option is given, any byte size value within bsrange
 zero_buffers   If this option is given, fio will init the IO buffers to
                all zeroes. The default is to fill them with random data.
 
 zero_buffers   If this option is given, fio will init the IO buffers to
                all zeroes. The default is to fill them with random data.
 

+refill_buffers If this option is given, fio will refill the IO buffers
+               on every submit. The default is to only fill it at init
+               time and reuse that data. Only makes sense if zero_buffers
+               isn't specified, naturally.
+

 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
 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


@@ -454,7 +459,11 @@ fsync=int  If writing to a file, issue a sync of the dirty data
                not sync the file. The exception is the sg io engine, which
                synchronizes the disk cache anyway.
 
                not sync the file. The exception is the sg io engine, which
                synchronizes the disk cache anyway.
 

-overwrite=bool If writing to a file, setup the file first and do overwrites.
+overwrite=bool If true, writes to a file will always overwrite existing
+               data. If the file doesn't already exist, it will be
+               created before the write phase begins. If the file exists
+               and is large enough for the specified write phase, nothing
+               will be done.

 
 end_fsync=bool If true, fsync file contents when the job exits.
 
 
 end_fsync=bool If true, fsync file contents when the job exits.
 


@@ -462,10 +471,6 @@ fsync_on_close=bool        If true, fio will fsync() a dirty file on close.
                This differs from end_fsync in that it will happen on every
                file close, not just at the end of the job.
 
                This differs from end_fsync in that it will happen on every
                file close, not just at the end of the job.
 

-rwmixcycle=int Value in milliseconds describing how often to switch between
-               reads and writes for a mixed workload. The default is
-               500 msecs.
-

 rwmixread=int  How large a percentage of the mix should be reads.
 
 rwmixwrite=int How large a percentage of the mix should be writes. If both
 rwmixread=int  How large a percentage of the mix should be reads.
 
 rwmixwrite=int How large a percentage of the mix should be writes. If both