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Diffstat (limited to 'gdb/testsuite/gdb.trace/tspeed.c')
| -rw-r--r-- | gdb/testsuite/gdb.trace/tspeed.c | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/gdb/testsuite/gdb.trace/tspeed.c b/gdb/testsuite/gdb.trace/tspeed.c new file mode 100644 index 0000000..cf698f9 --- /dev/null +++ b/gdb/testsuite/gdb.trace/tspeed.c @@ -0,0 +1,184 @@ +/* This testcase is part of GDB, the GNU debugger. + + Copyright 2010, 2011 + Free Software Foundation, Inc. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. */ + +/* This program tests tracepoint speed. It consists of two identical + loops, which in normal execution will run for exactly the same + amount of time. A tracepoint in the second loop will slow it down + by some amount, and then the program will report the slowdown + observed. */ + +/* While primarily designed for the testsuite, it can also be used + for interactive testing. */ + +#include <stdio.h> +#include <time.h> +#include <sys/time.h> +#include <sys/resource.h> + +int trace_speed_test (void); + +/* We mark these globals as volatile so the speed-measuring loops + don't get totally emptied out at high optimization levels. */ + +volatile int globfoo, globfoo2, globfoo3; + +volatile short globarr[80000]; + +int init_iters = 10 * 1000; + +int iters; + +int max_iters = 1000 * 1000 * 1000; + +int numtps = 1; + +unsigned long long now2, now3, now4, now5; +int total1, total2, idelta, mindelta, nsdelta; +int nspertp = 0; + +/* Return CPU usage (both user and system - trap-based tracepoints use + a bunch of system time). */ + +unsigned long long +myclock () +{ + struct timeval tm, tm2; + struct rusage ru; + getrusage (RUSAGE_SELF, &ru); + tm = ru.ru_utime; + tm2 = ru.ru_stime; + return (((unsigned long long) tm.tv_sec) * 1000000) + tm.tv_usec + + (((unsigned long long) tm2.tv_sec) * 1000000) + tm2.tv_usec; +} + +int +main(int argc, char **argv) +{ + int problem; + + iters = init_iters; + + while (1) + { + numtps = 1; /* set pre-run breakpoint here */ + + /* Keep trying the speed test, with more iterations, until + we get to a reasonable number. */ + while (problem = trace_speed_test()) + { + /* If iteration isn't working, give up. */ + if (iters > max_iters) + { + printf ("Gone over %d iterations, giving up\n", max_iters); + break; + } + if (problem < 0) + { + printf ("Negative times, giving up\n", max_iters); + break; + } + + iters *= 2; + printf ("Doubled iterations to %d\n", iters); + } + + printf ("Tracepoint time is %d ns\n", nspertp); + + /* This is for the benefit of interactive testing and attaching, + keeps the program from pegging the machine. */ + sleep (1); /* set post-run breakpoint here */ + + /* Issue a little bit of output periodically, so we can see if + program is alive or hung. */ + printf ("%s keeping busy, clock=%llu\n", argv[0], myclock ()); + } + return 0; +} + +int +trace_speed_test (void) +{ + int i; + + /* Overall loop run time deltas under 1 ms are likely noise and + should be ignored. */ + mindelta = 1000; + + // The bodies of the two loops following must be identical. + + now2 = myclock (); + globfoo2 = 1; + for (i = 0; i < iters; ++i) + { + globfoo2 *= 45; + globfoo2 += globfoo + globfoo3; + globfoo2 *= globfoo + globfoo3; + globfoo2 -= globarr[4] + globfoo3; + globfoo2 *= globfoo + globfoo3; + globfoo2 += globfoo + globfoo3; + } + now3 = myclock (); + total1 = now3 - now2; + + now4 = myclock (); + globfoo2 = 1; + for (i = 0; i < iters; ++i) + { + globfoo2 *= 45; + globfoo2 += globfoo + globfoo3; /* set tracepoint here */ + globfoo2 *= globfoo + globfoo3; + globfoo2 -= globarr[4] + globfoo3; + globfoo2 *= globfoo + globfoo3; + globfoo2 += globfoo + globfoo3; + } + now5 = myclock (); + total2 = now5 - now4; + + /* Report on the test results. */ + + nspertp = 0; + + idelta = total2 - total1; + + printf ("Loops took %d usec and %d usec, delta is %d usec, %d iterations\n", + total1, total2, idelta, iters); + + /* If the second loop seems to run faster, things are weird so give up. */ + if (idelta < 0) + return -1; + + if (idelta > mindelta + /* Total test time should be between 2 and 5 seconds. */ + && (total1 + total2) > (2 * 1000000) + && (total1 + total2) < (5 * 1000000)) + { + nsdelta = (((unsigned long long) idelta) * 1000) / iters; + printf ("Second loop took %d ns longer per iter than first\n", nsdelta); + nspertp = nsdelta / numtps; + printf ("%d ns per tracepoint\n", nspertp); + printf ("Base iteration time %d ns\n", + ((int) (((unsigned long long) total1) * 1000) / iters)); + printf ("Total test time %d secs\n", ((int) ((now5 - now2) / 1000000))); + + /* Speed test ran with no problem. */ + return 0; + } + + /* The test run was too brief, or otherwise not useful. */ + return 1; +} |