[netperf-talk] recent, interesting changes in top-of-trunk netperf2

[Rick Jones]

Folks -

I was enthused today :) and implemented a "sit and spin" mode for the paced send 
(--enable-intervals) support.  This will be part of netperf 2.4.2, and here is a 
preview of the Release_Notes:

*) There is now a -B global command-line argument that will append its
    parameter as a string to the end of result lines when test banners
    have been suppressed.  this is to make it easier to distinguish one
    result from another when aggregate restults are being run in
    parallel, without having to resort to having the individual results
    shell redirected to a file. This has been done for some of the
    tests in nettest_bsd.c, but not all of them, nor for the tests in
    the other nettest_mumble.c files.

*) There is now an --enable-spin configure option that will enable
    intervals if not already enabled and will have the sender sit and
    spin in a tight loop until time for the next interval rather than
    wait for an interval timer to expire.  This means it should be
    possible to have a much finer granularity on the interval, at the
    expense of an EXTREME increase in CPU utilization.  (To the extent
    I'm considering disabling measurement of local CPU utilization when
    that mode is enabled, and bursts have been requested - your
    feedback on that topic would be most appreciated)

    If only --enable-intervals is used with configure, the old set the
    interval timer and wait method is still used.

    If --enable-spin is configured, the test banner will include "spin
    intervals" rather than the "intervals" from a plain
    --enable-intervals.  The sit and spin will either use
    gettimeofday(), or gethrtime() if gethrtime() is available.

    This has been implemented in the tests of nettest_bsd.c but none of
    the others.  Volunteers would be most welcome.  I would entertain
    the notion of making the implementation a series of inline
    functions in netlib. This holds true for the demo mode - why will
    become clear when you look at nettest_bsd.c.  While things are
    considerably cleaner than they were before, with reuse within
    nettest_bsd.c, there is no resuse with the rest of the
    nettest_mumble.c files.

*) the -w option for the interval time now takes three optional
    suffixes. if the suffix is 'm' (eg 10m) it will assume the user has
    specified time in units of milliseconds.  if the suffix is 'u' it
    will assume microseconds, and if 's' seconds. no suffix remains
    milliseconds for backwards compatability with previous netperf
    versions.

*) It should be possible to successfully compile with
    --enable-intervals.

If you would like to play with the top of trunk, feel free to grab the bits from 
http://www.netperf.org/svn/netperf2/trunk/ via your friendly neighborhood 
subversion client.

happy benchmarking,

rick jones