On Thu, Jul 26, 2001 at 02:56:08PM +0300, Maxim Sobolev wrote:
> I am not sure that the error is what we want to get in this situation.
> Perhaps more *compatible* solution would be wait indefinitely if timeout
> is too large.

I guess this could cause problems for programs that use select to
time stuff accurately?

> Interesting, but this isn't really relevant to my question. I want to
> know why the program in question behaves difefrently when linked with
> and without -pthead flag (bug in libc_r?). Also [EINVAL] is not what
> I'm seeing here, because as you can easily check in my test case
> tv.tv_sec == 4294976, which is less that 1000000000 - upper limit of
> our select(2) implementation depicted in PR 18909.

I think I've found out what is wrong. All timing with the pthreads
library is actually implimented using poll, which takes a timeout
as an int in ms. The timeout you begin with is 2^32-1 as an unsigned
int and gets converted to a timeval and then a timespec and then
back to -1 as an int. Netgative timeouts are converted to zero and
so the code ends up spinning.

I guess what the code should do is set a non-zero timeout if this
sort of problem crops up. I think it will just end up trying the
timeout again when the short timer expires.

Try the patch below. I chose 31 seconds as the timeout 'cos 31
seconds will always be representable in ms in an int.


--- /tmp/dwmalone/uthread_kern.c        Fri Jul 27 14:44:52 2001
+++ uthread/uthread_kern.c      Fri Jul 27 14:49:10 2001
@@ -699,6 +699,9 @@
                         * Calculate the time left for the next thread to
                         * timeout:
+                       if (pthread->wakeup_time.tv_sec - ts.tv_sec > 31)
+                               timeout_ms = 31 * 1000;
+                       else
                        timeout_ms = ((pthread->wakeup_time.tv_sec - ts.tv_sec) *
                            1000) + ((pthread->wakeup_time.tv_nsec - ts.tv_nsec) /

To Unsubscribe: send mail to [EMAIL PROTECTED]
with "unsubscribe freebsd-current" in the body of the message

Reply via email to