nanosleep() replacement Take 2

[Darren Tucker]

Gert Doering wrote:
> Tested on SCO OSR 3.0.  openssh-current (as of right now) with your
> appended patch.  Configures, compiles, and "scp -l <number>" seems to
> do things that correlate with the specified number (I assume it's
> kbit/second and the progress bar is Kbyte/second).

Yes that's the case.

> -l is fairly unprecise, but this is likely due to a fairly slow machine,
> select()/scheduler granularity, and other things eating CPU.

I saw that too with Tim's function but I was able to get pretty good
results (5% variance or less from specified bandwidth) on a somewhat
loaded 170 MHz SPARC.

I suspect there's some cases it doesn't handle correctly (I'm trying to
find an example).

Would you mind trying the following function for comparison?

		-Daz.

int nanosleep(const struct timespec *req, struct timespec *rem)
{
       int rc;
       extern int errno;
       int saverrno;
       struct timeval tstart, tstop, tremain, time2wait;

       TIMESPEC_TO_TIMEVAL(&time2wait, req)

       gettimeofday(&tstart, NULL);
       rc = select(0, NULL, NULL, NULL, &time2wait);
       saverrno = errno;
       gettimeofday (&tstop, NULL);

       tremain.tv_sec = tstop.tv_sec - tstart.tv_sec - time2wait.tv_sec;
       tremain.tv_usec = tstop.tv_usec - tstart.tv_usec -
time2wait.tv_usec;
       tremain.tv_sec += tremain.tv_usec / 1000000L;
       tremain.tv_usec %= 1000000L;
       TIMEVAL_TO_TIMESPEC(&tremain, rem)

       if (rc < 0) {
               rc = -1;
               errno = saverrno;
       }
       return(rc);
}

-- 
Darren Tucker (dtucker at zip.com.au)
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    Good judgement comes with experience. Unfortunately, the experience
usually comes from bad judgement.