fio: add hipri option to sg engine

[fio.git] / fio.1

diff --git a/fio.1 b/fio.1
index d477b508398ef9489d77b5fce75e373239450c35..9636a85f51cb200cd84cc80e876cc7583bdf326c 100644 (file)
--- a/fio.1
+++ b/fio.1
@@ -2114,6 +2114,16 @@ client and the server or in certain loopback configurations.
 Specify stat system call type to measure lookup/getattr performance.
 Default is \fBstat\fR for \fBstat\fR\|(2).
 .TP
+.BI (sg)hipri
+If this option is set, fio will attempt to use polled IO completions. This
+will have a similar effect as (io_uring)hipri. Only SCSI READ and WRITE
+commands will have the SGV4_FLAG_HIPRI set (not UNMAP (trim) nor VERIFY).
+Older versions of the Linux sg driver that do not support hipri will simply
+ignore this flag and do normal IO. The Linux SCSI Low Level Driver (LLD)
+that "owns" the device also needs to support hipri (also known as iopoll
+and mq_poll). The MegaRAID driver is an example of a SCSI LLD.
+Default: clear (0) which does normal (interrupted based) IO.
+.TP
 .BI (sg)readfua \fR=\fPbool
 With readfua option set to 1, read operations include the force
 unit access (fua) flag. Default: 0.