900
Subj : Re: pthread_cond_timedwait problems
To   : comp.programming.threads
From : markh@compro.net
Date : Tue Aug 16 2005 03:16 am

> I guess the nsec member of the timeval struct was misleading me. I
> should have known better.

    Huh?

I meant the timespec member. I just ignorantly assumed since the
structure used had a nsec  member, that I would get that (or close)
resolution. I understand better  now what is happening except for one
thing. I consistantly get results I might have originally expected when
using delays shorter than HZ. The below are using a 2.6.12.4 kernel
BTW. What is really happening there?

Attempting  delay of   100 nsec (0 usecs)
gettimeofday returned  1124183504 sec   963619    usec
New delay struct       1124183504 sec   963619100 nsec
Actual usec delay from timer =  11 usecs

Attempting  delay of   1000 nsec (1 usecs)
gettimeofday returned  1124183504 sec   963684    usec
New delay struct       1124183504 sec   963685000 nsec
Actual usec delay from timer =  5 usecs

Attempting  delay of   10000 nsec (10 usecs)
gettimeofday returned  1124183504 sec   963723    usec
New delay struct       1124183504 sec   963733000 nsec
Actual usec delay from timer =  6 usecs

Attempting  delay of   100000 nsec (100 usecs)
gettimeofday returned  1124183504 sec   963796    usec
New delay struct       1124183504 sec   963896000 nsec
Actual usec delay from timer =  1960 usecs

Attempting  delay of   1000000 nsec (1000 usecs)
gettimeofday returned  1124183504 sec   965802    usec
New delay struct       1124183504 sec   966802000 nsec
Actual usec delay from timer =  1955 usecs

Attempting  delay of   10000000 nsec (10000 usecs)
gettimeofday returned  1124183504 sec   967798    usec
New delay struct       1124183504 sec   977798000 nsec
Actual usec delay from timer =  10956 usecs

Attempting  delay of   100000000 nsec (100000 usecs)
gettimeofday returned  1124183504 sec   978795    usec
New delay struct       1124183505 sec   78795000 nsec
Actual usec delay from timer =  100932 usecs

Attempting  delay of   1000000000 nsec (1000000 usecs)
gettimeofday returned  1124183505 sec   79776    usec
New delay struct       1124183506 sec   79776000 nsec
Actual usec delay from timer =  1001693 usecs 

Thanks

.

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