X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=HOWTO;h=662ebe32acf2e10c1956f8f768171da2f92de244;hp=aec00e84e548f1c9d65952e73803d8fcb5df53e9;hb=74929ac27bcbaa26a08a9abcda70b5ebba94166e;hpb=a1c58075279454a91ec43366846b93e8dcf9753c;ds=sidebyside

diff --git a/HOWTO b/HOWTO
index aec00e84..662ebe32 100644
--- a/HOWTO
+++ b/HOWTO
@@ -158,6 +158,9 @@ specify:
 
 $ fio --name=random-writers --ioengine=libaio --iodepth=4 --rw=randwrite --bs=32k --direct=0 --size=64m --numjobs=4
 
+4.1 Environment variables
+-------------------------
+
 fio also supports environment variable expansion in job files. Any
 substring of the form "${VARNAME}" as part of an option value (in other
 words, on the right of the `='), will be expanded to the value of the
@@ -188,6 +191,20 @@ numjobs=4
 fio ships with a few example job files, you can also look there for
 inspiration.
 
+4.2 Reserved keywords
+---------------------
+
+Additionally, fio has a set of reserved keywords that will be replaced
+internally with the appropriate value. Those keywords are:
+
+$pagesize	The architecture page size of the running system
+$mb_memory	Megabytes of total memory in the system
+$ncpus		Number of online available CPUs
+
+These can be used on the command line or in the job file, and will be
+automatically substituted with the current system values when the job
+is run.
+
 
 5.0 Detailed list of parameters
 -------------------------------