On Wed, Jun 18, 2003 at 09:09:59PM +1000, Martin Pool wrote:
> On 17 Jun 2003, Rogier Wolff <[EMAIL PROTECTED]> wrote:
> >
> > Oops. Missed one line in the last patch....
>
> Thankyou. That looks good.
>
> If we're going to make this more accurate it might be worthwhile to
> actually look at how long we really did sleep for, and use that to
> adjust time_to_sleep rather than resetting to zero.
That would have to be a platform specific thing since not
all systems modify the timeout value to reflect the amount
of time not slept. Nevertheless that is a nice idea.
> Also I'd prefer the variable be called micros_to_sleep or
> us_to_sleep. Small point I know.
I'm not too keen on forcing the minimum sleep to be 100ms.
That is just too coarse for my taste and tends produce
fits-and-starts stalling on very slow links.
This should be balanced with the "Smoother bandwidth limiting"
thread. Perhaps setting a minimum sleep to 10ms or
a period based on the value of bwlimit.
> > diff -ur rsync-2.5.6.orig/io.c rsync-2.5.6/io.c
> > +++ rsync-2.5.6/io.c Tue Jun 17 23:43:49 2003
> > @@ -416,10 +416,19 @@
> > * use a bit less bandwidth than specified, because it doesn't make up
> > * for slow periods. But arguably this is a feature. In addition, we
> > * ought to take the time used to write the data into account.
> > + *
> > + * During some phases of big transfers (file XXX is uptodate) this is
> > + * called with a small bytes_written every time. As the kernel has to
> > + * round small waits up to guarantee that we actually wait at least
> > + * the requested number of microseconds, this can become grossly
> > + * inaccurate. We therefore keep a cumulating number of microseconds
> > + * to wait, and only actually perform the sleep when the rouding
> > + * becomes insignificant. (less than 10%) -- REW.
> > **/
> > static void sleep_for_bwlimit(int bytes_written)
> > {
> > struct timeval tv;
> > + static int time_to_sleep = 0;
> >
> > if (!bwlimit)
> > return;
> > @@ -427,9 +436,13 @@
> > assert(bytes_written > 0);
> > assert(bwlimit > 0);
> >
> > - tv.tv_usec = bytes_written * 1000 / bwlimit;
> > - tv.tv_sec = tv.tv_usec / 1000000;
> > - tv.tv_usec = tv.tv_usec % 1000000;
> > + time_to_sleep += bytes_written * 1000 / bwlimit;
> > +
> > + if (time_to_sleep < 100000) return;
> > +
> > + tv.tv_sec = time_to_sleep / 1000000;
> > + tv.tv_usec = time_to_sleep % 1000000;
> > + time_to_sleep = 0;
> >
> > select(0, NULL, NULL, NULL, &tv);
> > }
>
> --
> Martin
> --
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J.W. Schultz Pegasystems Technologies
email address: [EMAIL PROTECTED]
Remember Cernan and Schmitt
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