On Sat, 2 May 2020, [email protected] wrote:
> A couple of further questions embedded:
>
> A question on the std-dev -- is this for "n" measures as defined
> by -r interval? "ping" reports an N packets transmitted. Maybe
> this is obvious but your revised manpage doesn't say. Could this
> be added to the output report?
Correct: the summary stats are computed over the periodic throughput
statistics. I have tried to make this clearer in the man page.
Note however: for simplicity the summary duration covers the interval from
first transfer to process exit. This though may differ significantly from
the sum of sample durations only for the server, as only it may fall idle
during the session.
I did consider adding the number of samples and their duration to the
summary but discarded it early on as possibly misleading for that reason
(and, as a cosmetic thing, it required another line of output).
cheers,
Richard.
Index: tcpbench.1
===================================================================
RCS file: /cvs/src/usr.bin/tcpbench/tcpbench.1,v
retrieving revision 1.26
diff -u -p -u -p -r1.26 tcpbench.1
--- tcpbench.1 12 Feb 2020 14:46:36 -0000 1.26
+++ tcpbench.1 2 May 2020 20:49:02 -0000
@@ -65,14 +65,23 @@ of a listening server to connect to.
.Pp
Once connected, the client will send TCP or UDP traffic as fast as possible to
the server.
-Both the client and server will periodically display throughput
-statistics along with any kernel variables the user has selected to
+Both the client and server will periodically compute and display throughput
+statistics.
+The server starts computing these for UDP on receipt of the first datagram,
+and stops for TCP when it has no connections.
+This display also includes any kernel variables the user has selected to
sample (using the
.Fl k
option, which is only available in TCP mode).
A list of available kernel variables may be obtained using the
.Fl l
option.
+.Pp
+A summary over the periodic throughput statistics is displayed on exit.
+Its accuracy may be increased by decreasing the
+.Ar interval .
+The summary bytes and duration cover the interval from transfer start
+to process exit.
.Pp
The options are as follows:
.Bl -tag -width Ds
