joel@intelisc.UUCP (Joel Clark) (06/17/88)
_____________________________________________________________________ weiser.pa@xerox.com writes: >#include <sys/time.h> > >main() > { > struct timeval tv; > > tv.tv_sec = 0; > tv.tv_usec = 100000; > for( ;; ) > select( 0, 0, 0, 0, &tv ); > } > > I changed 100000 to 25000, and ran 18 of these on my > Sun-4/260 with 120MB swap and 24MB ram, with very little else going on. > Perfmeter shows no disk activity, ps aux shows each of the 18 using almost no > cpu. Each of the 18 has more than millisecond to get in and out of select, > which is certainly enough. And the system is to its knees! If it doesn't > work for you, try 19 or 20 or 21. Window refreshes take 10's of seconds. If I > kill off 3 of these, all is back to normal. > > I don't have a 60C to try this on. But, try reducing that delay factor and see > if you also see a knee in the performance curve well before the cpu should > be swamped. (And in any case, swamped cpu doesn't need to imply knee in the > curve...) > -mark > Some people wanted to know if the Knee showed up in a Sun 386i Road Runner. I tried this program yesterday with 100000 changed to 25000. Performance drops off the edge of usefulness at about 20 processes. Joel Clark Intel Scientific Computers joel@intelisc.UUCP.COM Beaverton, Oregon 97201 {tektronix}!ogcvax!intelisc!joel (503) 629-7732