topic Re: Interrupt delay in Pthreads in Operating System - OpenVMS

Interrupt delay in Pthreads

Elwin Tennant — Tue, 27 Apr 2010 13:42:37 GMT

The attached C program writes 'ABCD' to the screen. However it shows a delay of about 1/5 second between characters !

The log file under VMS (Integrity) shows:
7.546: 'B' /C1 main: sending a character to tty
7.546: /55 clk: requesting interrupt
7.646: /55 clk: requesting interrupt
7.746: /A1 tty: received a command
7.746: 'B' /A2 tty: character written

Under Linux it shows:
13.469: 'C' /C1 main: sending a character to tty
13.469: /A1 tty: received a command
13.469: 'C' /A2 tty: character written

The delay may be in pthread_mutex_lock

Try it and see what you get !?

Re: Interrupt delay in Pthreads

H.Becker — Tue, 27 Apr 2010 14:08:18 GMT

Did you enable UPCALLS by linking with /threads=uppcalls or set image flag=upcalls?

Re: Interrupt delay in Pthreads

Elwin Tennant — Tue, 27 Apr 2010 14:14:57 GMT

It certainly looks a lot better !! We will do some more tests. Many thanks.

Re: Interrupt delay in Pthreads

Volker Halle — Tue, 27 Apr 2010 15:43:42 GMT

Elwin,

welcome to the OpenVMS ITRC forum.

Here is a good explanation about DECthreads and 'upcalls':

http://h71000.www7.hp.com/wizard/wiz_0446.html

Volker.