After considerable testing/frustration, I have determined that the use of POSIX::times() in my Serial I/O application is causing blocks of serial input characters to be occassionally lost (presumably because interrupts, or perhaps task switching, are being disabled for too long). I am using POSIX::times() simply to measure elapsed time with greater than one second resolution (e.g. for receive timeouts).

I looked on CPAN for the "source" code to POSIX, but did not find "enough" code to determine what "times" is doing. I have not used Timer::HiRes as I was hoping to stay with core components for this application.

Configuration: Redhat 9, Perl 5.8.0, 1 or 2 serial ports at 19,200 using POSIX::termios (works fine w/o POSIX::times).

Questions:
1. Does anyone know what the POSIX::times routine is doing ?
2. If I limit myself to one second resolution with "time" am I likely to eliminate the interrupt overrun problem ?
3. When a module is implemented using XS, is all of the code present in a *.pm module, or is there another file somewhere else ?

Thanks.

In reply to POSIX::times() cause SIO overrun by Anonymous Monk

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