diff options
Diffstat (limited to 'src/bin/pg_test_timing/pg_test_timing.c')
-rw-r--r-- | src/bin/pg_test_timing/pg_test_timing.c | 186 |
1 files changed, 153 insertions, 33 deletions
diff --git a/src/bin/pg_test_timing/pg_test_timing.c b/src/bin/pg_test_timing/pg_test_timing.c index ce7aad4b25a..a5621251afc 100644 --- a/src/bin/pg_test_timing/pg_test_timing.c +++ b/src/bin/pg_test_timing/pg_test_timing.c @@ -9,19 +9,30 @@ #include <limits.h> #include "getopt_long.h" +#include "port/pg_bitutils.h" #include "portability/instr_time.h" static const char *progname; static unsigned int test_duration = 3; +static double max_rprct = 99.99; + +/* record duration in powers of 2 nanoseconds */ +static long long int histogram[32]; + +/* record counts of first 10K durations directly */ +#define NUM_DIRECT 10000 +static long long int direct_histogram[NUM_DIRECT]; + +/* separately record highest observed duration */ +static int32 largest_diff; +static long long int largest_diff_count; + static void handle_args(int argc, char *argv[]); static uint64 test_timing(unsigned int duration); static void output(uint64 loop_count); -/* record duration in powers of 2 microseconds */ -static long long int histogram[32]; - int main(int argc, char *argv[]) { @@ -44,6 +55,7 @@ handle_args(int argc, char *argv[]) { static struct option long_options[] = { {"duration", required_argument, NULL, 'd'}, + {"cutoff", required_argument, NULL, 'c'}, {NULL, 0, NULL, 0} }; @@ -56,7 +68,7 @@ handle_args(int argc, char *argv[]) { if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0) { - printf(_("Usage: %s [-d DURATION]\n"), progname); + printf(_("Usage: %s [-d DURATION] [-c CUTOFF]\n"), progname); exit(0); } if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0) @@ -66,7 +78,7 @@ handle_args(int argc, char *argv[]) } } - while ((option = getopt_long(argc, argv, "d:", + while ((option = getopt_long(argc, argv, "d:c:", long_options, &optindex)) != -1) { switch (option) @@ -93,6 +105,26 @@ handle_args(int argc, char *argv[]) } break; + case 'c': + errno = 0; + max_rprct = strtod(optarg, &endptr); + + if (endptr == optarg || *endptr != '\0' || errno != 0) + { + fprintf(stderr, _("%s: invalid argument for option %s\n"), + progname, "--cutoff"); + fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname); + exit(1); + } + + if (max_rprct < 0 || max_rprct > 100) + { + fprintf(stderr, _("%s: %s must be in range %u..%u\n"), + progname, "--cutoff", 0, 100); + exit(1); + } + break; + default: fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname); @@ -111,7 +143,6 @@ handle_args(int argc, char *argv[]) exit(1); } - printf(ngettext("Testing timing overhead for %u second.\n", "Testing timing overhead for %u seconds.\n", test_duration), @@ -130,23 +161,33 @@ test_timing(unsigned int duration) end_time, temp; - total_time = duration > 0 ? duration * INT64CONST(1000000) : 0; + /* + * Pre-zero the statistics data structures. They're already zero by + * default, but this helps bring them into processor cache and avoid + * possible timing glitches due to COW behavior. + */ + memset(direct_histogram, 0, sizeof(direct_histogram)); + memset(histogram, 0, sizeof(histogram)); + largest_diff = 0; + largest_diff_count = 0; + + total_time = duration > 0 ? duration * INT64CONST(1000000000) : 0; INSTR_TIME_SET_CURRENT(start_time); - cur = INSTR_TIME_GET_MICROSEC(start_time); + cur = INSTR_TIME_GET_NANOSEC(start_time); while (time_elapsed < total_time) { int32 diff, - bits = 0; + bits; prev = cur; INSTR_TIME_SET_CURRENT(temp); - cur = INSTR_TIME_GET_MICROSEC(temp); + cur = INSTR_TIME_GET_NANOSEC(temp); diff = cur - prev; /* Did time go backwards? */ - if (diff < 0) + if (unlikely(diff < 0)) { fprintf(stderr, _("Detected clock going backwards in time.\n")); fprintf(stderr, _("Time warp: %d ms\n"), diff); @@ -154,25 +195,37 @@ test_timing(unsigned int duration) } /* What is the highest bit in the time diff? */ - while (diff) - { - diff >>= 1; - bits++; - } + if (diff > 0) + bits = pg_leftmost_one_pos32(diff) + 1; + else + bits = 0; /* Update appropriate duration bucket */ histogram[bits]++; + /* Update direct histogram of time diffs */ + if (diff < NUM_DIRECT) + direct_histogram[diff]++; + + /* Also track the largest observed duration, even if >= NUM_DIRECT */ + if (diff > largest_diff) + { + largest_diff = diff; + largest_diff_count = 1; + } + else if (diff == largest_diff) + largest_diff_count++; + loop_count++; INSTR_TIME_SUBTRACT(temp, start_time); - time_elapsed = INSTR_TIME_GET_MICROSEC(temp); + time_elapsed = INSTR_TIME_GET_NANOSEC(temp); } INSTR_TIME_SET_CURRENT(end_time); INSTR_TIME_SUBTRACT(end_time, start_time); - printf(_("Per loop time including overhead: %0.2f ns\n"), + printf(_("Average loop time including overhead: %0.2f ns\n"), INSTR_TIME_GET_DOUBLE(end_time) * 1e9 / loop_count); return loop_count; @@ -181,28 +234,95 @@ test_timing(unsigned int duration) static void output(uint64 loop_count) { - int64 max_bit = 31, - i; - char *header1 = _("< us"); - char *header2 = /* xgettext:no-c-format */ _("% of total"); - char *header3 = _("count"); + int max_bit = 31; + const char *header1 = _("<= ns"); + const char *header1b = _("ns"); + const char *header2 = /* xgettext:no-c-format */ _("% of total"); + const char *header3 = /* xgettext:no-c-format */ _("running %"); + const char *header4 = _("count"); int len1 = strlen(header1); int len2 = strlen(header2); int len3 = strlen(header3); + int len4 = strlen(header4); + double rprct; + bool stopped = false; /* find highest bit value */ while (max_bit > 0 && histogram[max_bit] == 0) max_bit--; + /* set minimum column widths */ + len1 = Max(8, len1); + len2 = Max(10, len2); + len3 = Max(10, len3); + len4 = Max(10, len4); + printf(_("Histogram of timing durations:\n")); - printf("%*s %*s %*s\n", - Max(6, len1), header1, - Max(10, len2), header2, - Max(10, len3), header3); - - for (i = 0; i <= max_bit; i++) - printf("%*ld %*.5f %*lld\n", - Max(6, len1), 1l << i, - Max(10, len2) - 1, (double) histogram[i] * 100 / loop_count, - Max(10, len3), histogram[i]); + printf("%*s %*s %*s %*s\n", + len1, header1, + len2, header2, + len3, header3, + len4, header4); + + rprct = 0; + for (int i = 0; i <= max_bit; i++) + { + double prct = (double) histogram[i] * 100 / loop_count; + + rprct += prct; + printf("%*ld %*.4f %*.4f %*lld\n", + len1, (1L << i) - 1, + len2, prct, + len3, rprct, + len4, histogram[i]); + } + + printf(_("\nObserved timing durations up to %.4f%%:\n"), max_rprct); + printf("%*s %*s %*s %*s\n", + len1, header1b, + len2, header2, + len3, header3, + len4, header4); + + rprct = 0; + for (int i = 0; i < NUM_DIRECT; i++) + { + if (direct_histogram[i]) + { + double prct = (double) direct_histogram[i] * 100 / loop_count; + bool print_it = !stopped; + + rprct += prct; + + /* if largest diff is < NUM_DIRECT, be sure we print it */ + if (i == largest_diff) + { + if (stopped) + printf("...\n"); + print_it = true; + } + + if (print_it) + printf("%*d %*.4f %*.4f %*lld\n", + len1, i, + len2, prct, + len3, rprct, + len4, direct_histogram[i]); + if (rprct >= max_rprct) + stopped = true; + } + } + + /* print largest diff when it's outside the array range */ + if (largest_diff >= NUM_DIRECT) + { + double prct = (double) largest_diff_count * 100 / loop_count; + + printf("...\n"); + printf("%*d %*.4f %*.4f %*lld\n", + len1, largest_diff, + len2, prct, + len3, 100.0, + len4, largest_diff_count); + } } |