Re: How to time speed of "write" on unix socket?
Re: How to time speed of "write" on unix socket?
- Subject: Re: How to time speed of "write" on unix socket?
- From: Peter Sichel <email@hidden>
- Date: Sun, 25 Jan 2004 17:09:37 -0500
Since TCP guarantees end-to-end reliability and includes built-in flow
control,
you don't really know when a specific data segment has been sent (or
repeated)
until you receive an acknowledgment from the other end. It might make
more
sense to measure end-to-end performance.
Next, if you want to measure "application" versus network performance,
consider using the loopback address to connect to a server on the same
host as the client. You can either develop a stub server for the
purpose
of measuring traffic, or use sysctl to examine your TCP connection
statistics.
If you choose the stub server approach, you time-stamp when each packet
arrives using the SO_timestamp option. By measuring when successive
packets
arrive and the amount of data they contain, you can get a pretty handle
and the effective data rate.
- Peter
On Jan 25, 2004, at 1:50 AM, Larry Gerndt wrote:
I'm in the process of benchmarking my app's performance, and one of
the
areas I looked at was transmission speed (my app is a client which
sends
data to a host server using a unix socket). Since my socket is set for
blocking, I assumed all I had to do time transmission speed was check
::UpTime before and after the socket "write" call. However, the
interval
I'm reading is way smaller than it could possibly be (for example, 55
uSec
to write 17Kbytes). This makes me think that all my "write" is really
doing
is writing to the local TCP buffer, is that correct? If so, how do I
measure the socket's actual transmission speed to the host? Thanks in
advance.
--
Larry Gerndt
AIM Handle: SonOfTheSonOfMan
Let the truth be told though the heavens fall -- James Garrison
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