Clarify spread/lambda of poisson

Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/HOWTO b/HOWTO
index e259aa7f07c26f0335d71c025fe7498946823020..a534aa865d8c4a9384ebee3d823ecaaaf0fdfb3d 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -1070,7 +1070,8 @@ rate_process=str  This option controls how fio manages rated IO
                adjusted based on IO completion rates. If this is set to
                'poisson', fio will submit IO based on a more real world
                random request flow, known as the Poisson process
-               (https://en.wikipedia.org/wiki/Poisson_process).
+               (https://en.wikipedia.org/wiki/Poisson_process). The lambda
+               will be 10^6 / IOPS for the given workload.
 
 latency_target=int     If set, fio will attempt to find the max performance
                point that the given workload will run at while maintaining a

diff --git a/fio.1 b/fio.1
index 6f72ec0f910a6d12bc6cc6f949b765d5f4988b38..3cc353a3c02a698f709fc6bce6cdbeefec5124d7 100644 (file)
--- a/fio.1
+++ b/fio.1
@@ -969,7 +969,8 @@ This option controls how fio manages rated IO submissions. The default is
 IOs that gets adjusted based on IO completion rates. If this is set to
 \fBpoisson\fR, fio will submit IO based on a more real world random request
 flow, known as the Poisson process
-(https://en.wikipedia.org/wiki/Poisson_process).
+(https://en.wikipedia.org/wiki/Poisson_process). The lambda will be
+10^6 / IOPS for the given workload.
 .TP
 .BI rate_cycle \fR=\fPint
 Average bandwidth for \fBrate\fR and \fBrate_min\fR over this number of