Messages in this thread | | | Date | Mon, 29 Jan 2001 01:02:02 +0100 | From | Pavel Machek <> | Subject | Re: 2.4 Cpu usuage (display oddities more than anything) |
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Hi!
> Some oddities w/kapmd(2.4.0)... If I sit in X and do nothing other than run top or > "vmstat 5", I get down to as low as 60% idle and 40% in system -- with kapmd getting > 'charged' for the 40%.
At least you can see how kapmd mechanism actually works.
> Then I go and run 'freeamp' and the CPU usage goes to 100% idle, presumably because > kapmd never gets called because it's never in the idle loop for longer than 333ms. > > It's just weird and unnatural. > > Also forgive my ignorance but is it really possible playing VBR MP3's takes 0 measurable > CPU? I've run the program for hours and a ps of 'freeamp' show either no measured cpu > time or maybe 1 second...the kernel runs at at 100% idle for most of the time. > I thought mp3 decompression was a cpu intensive > operation....weird...
Those counters are running. Try this one:
/* * This is simple program which should show weak spots in linux's scheduler */
#include <stdio.h> #include <time.h> #include <sys/timeb.h> #include <unistd.h>
int startgame;
int ticks( void ) { struct timeb tb; int sec, msec; ftime( &tb ); sec = tb.time - startgame; msec = tb.millitm; return sec * 1000 + msec; }
void main( int argc, char *argv[] ) { int delta, badboy = 0, count = 1000000; int t1, t2;
startgame = time(NULL); if (argc>1) { badboy = 1; printf( "I'm a *BAD* boy! " ); usleep( 100000 ); t1 = ticks(); usleep( 100000 ); t2 = ticks(); delta = t2-t1; printf( "And bad boys know that jiffie is %dmsec\n", delta ); delta = 10; } else { printf( "I'm a good boy.\n" ); delta = 20; } while(1) { if ((ticks()-t1) % delta > ((delta * 17)/20)) if (badboy) usleep(10000); if (!((--count)%100000)) { printf( "." ); fflush( stdout ); } if (!count) break; } }
it used to work. Bad boy used to be charged 0% cpu even if it ate 70%
> I guess I'm thinking -- maybe time in kapmd should be counted as 'idle'?
-- I'm pavel@ucw.cz. "In my country we have almost anarchy and I don't care." Panos Katsaloulis describing me w.r.t. patents at discuss@linmodems.org - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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