question about --bwlimit=

[Wayne Davison]

On Fri, May 21, 2004 at 02:48:12PM -0400, Wallace Matthews wrote:
> I can repeat this time after time. If --bwlimit is > 4000 (ie. 4005,
> 4025, 4050,5000,7500,10000,100000) real is in the same range as 4001.
> If --bwlimit is 4000 or under (ie. 3725, 2000, 1000, 100) real is in
> the same range as 4000.

That is because of this calculation:

    tv.tv_usec = bytes_written * 1000 / bwlimit;

Rsync calls this function after a lot of 4-byte writes, and thus the
sleep time for "4 * 1000 / 4001" (or anything higher than 4001) is 0.
Thus, rsync neglects a bunch of sleep calls (but not all of them).

I'm looking into some of the old bwlimit patches to see about improving
this.

..wayne..