Messages in this thread | | | Subject | Re: [PATCH] elapsed times wrap | From | Albert Cahalan <> | Date | 24 Feb 2003 17:00:45 -0500 |
| |
Hugh Dickins writes: > On Sat, 22 Feb 2003, Kai Germaschewski wrote: >> On Sat, 22 Feb 2003, Hugh Dickins wrote:
>>> Userspace shows huge elapsed time across jiffies wrap: >>> with USER_HZ less then HZ, sys_times needs jiffies_64 >>> to calculate its retval. >> >> That makes me wonder, aren't all uses of >> jiffies_to_clock_t() broken then? > > I believe you're right, but it's less obvious to me > that the other uses really want fixing e.g. would we > be happy to maintain utime,stime,cutime,cstime as > 64-bit on a 32-bit machine? > >> Well, all which take an absolute time as an argument at least. > > Yes, it's much more important to fix those where userspace > habitually takes the difference. That certainly applies > to the return value from sys_times, but I don't see any > other cases as clear (though userspace may have good reason > to take the difference of any of them). > > Perhaps a procps expert can advise?
That depends on how much you care about the problems. Some that come to mind:
The OOM killer will be more likely to kill the wrong process. CPU usage stats will be worthless junk.
On a 4-way box, you can hit troubles with cutime after just 2 weeks of usage.
Consider changing just cutime. It's the value most likely to wrap. Plain utime would be the second priority.
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |