fio docs corrections

Correct fio mailing list address and unit of time for cpuchunks.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/HOWTO b/HOWTO
index f4f596a..26a9b93 100644
--- a/HOWTO
+++ b/HOWTO
@@ -874,7 +874,7 @@
 		percentage of CPU cycles.
 
 cpuchunks=int	If the job is a CPU cycle eater, split the load into
-		cycles of the given time. In milliseconds.
+		cycles of the given time. In microseconds.
 
 disk_util=bool	Generate disk utilization statistics, if the platform
 		supports it. Defaults to on.