Messages in this thread | | | Date | Thu, 30 Jan 1997 16:01:55 -0800 | From | Daniel Quinlan <> | Subject | strange `time' results on dual-processor P6 systems |
| |
We are attempting to use time(1) to gather some basic performance statistics on both single and dual-processor P6-200 systems. The kernel version is 2.0.27. The results appear to be quite wrong.
On a single-processor system, the time values for a test program are:
9.63user 0.18system 0:09.80elapsed 100%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (49major+3912minor)pagefaults 0swaps
9.67user 0.16system 0:09.84elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (49major+3912minor)pagefaults 0swaps
9.62user 0.19system 0:09.81elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (49major+3912minor)pagefaults 0swaps
On the dual-processor system, the time values are:
0.02user 10.47system 0:10.50elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (0major+0minor)pagefaults 0swaps
0.43user 10.06system 0:10.50elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (0major+0minor)pagefaults 0swaps
1.73user 8.76system 0:10.50elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (0major+0minor)pagefaults 0swaps
The elapsed time seems correct on both systems. However, the proportion of user to system time is more or less reversed and quite wrong for the dual-processor system.
Any ideas?
This is the test program:
------- start of cut text -------------- #include <stdio.h>
int a[4000000]; main() { int i, j; for( i=0; i<30; ++i ) { for( j=0; j<4000000; ++j ) ++a[j]; } return( 0 ); } ------- end ----------------------------
-- Daniel Quinlan (at work) Daniel Quinlan (otherwise) quinlan@transmeta.com http://www.pathname.com/~quinlan/
| |