From: Mike Galbraith Date: Mon, 25 May 2009 07:57:56 +0000 (+0200) Subject: perf top: Reduce display overhead X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=d94b943054721c346b0881865d645f000cd19880;p=linux-beck.git perf top: Reduce display overhead Iterate over the symbol table once per display interval, and copy/sort/tally/decay only those symbols which are active. Before: top - 10:14:53 up 4:08, 17 users, load average: 1.17, 1.53, 1.49 Tasks: 273 total, 5 running, 268 sleeping, 0 stopped, 0 zombie Cpu(s): 6.9%us, 38.2%sy, 0.0%ni, 19.9%id, 0.0%wa, 0.0%hi, 35.0%si, 0.0%st PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ P COMMAND 28504 root 20 0 1044 260 164 S 58 0.0 0:04.19 2 netserver 28499 root 20 0 1040 412 316 R 51 0.0 0:04.15 0 netperf 28500 root 20 0 1040 408 316 R 50 0.0 0:04.14 1 netperf 28503 root 20 0 1044 260 164 S 50 0.0 0:04.01 1 netserver 28501 root 20 0 1044 260 164 S 49 0.0 0:03.99 0 netserver 28502 root 20 0 1040 412 316 S 43 0.0 0:03.96 2 netperf 28468 root 20 0 1892m 325m 972 S 16 10.8 0:10.50 3 perf 28467 root 20 0 1892m 325m 972 R 2 10.8 0:00.72 3 perf After: top - 10:16:30 up 4:10, 17 users, load average: 2.27, 1.88, 1.62 Tasks: 273 total, 6 running, 267 sleeping, 0 stopped, 0 zombie Cpu(s): 2.5%us, 39.7%sy, 0.0%ni, 24.6%id, 0.0%wa, 0.0%hi, 33.3%si, 0.0%st PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ P COMMAND 28590 root 20 0 1040 412 316 S 54 0.0 0:07.85 2 netperf 28589 root 20 0 1044 260 164 R 54 0.0 0:07.84 0 netserver 28588 root 20 0 1040 412 316 R 50 0.0 0:07.89 1 netperf 28591 root 20 0 1044 256 164 S 50 0.0 0:07.82 1 netserver 28587 root 20 0 1040 408 316 R 47 0.0 0:07.61 0 netperf 28592 root 20 0 1044 260 164 R 47 0.0 0:07.85 2 netserver 28378 root 20 0 8732 1300 860 R 2 0.0 0:01.81 3 top 28577 root 20 0 1892m 165m 972 R 2 5.5 0:00.48 3 perf 28578 root 20 0 1892m 165m 972 S 2 5.5 0:00.04 3 perf [ Impact: optimization ] Signed-off-by: Mike Galbraith Acked-by: Peter Zijlstra LKML-Reference: Signed-off-by: Ingo Molnar --- diff --git a/Documentation/perf_counter/builtin-top.c b/Documentation/perf_counter/builtin-top.c index 74021ac90f51..4bed265926dd 100644 --- a/Documentation/perf_counter/builtin-top.c +++ b/Documentation/perf_counter/builtin-top.c @@ -374,18 +374,26 @@ static struct sym_entry tmp[MAX_SYMS]; static void print_sym_table(void) { - int i, printed; + int i, j, active_count, printed; int counter; float events_per_sec = events/delay_secs; float kevents_per_sec = (events-userspace_events)/delay_secs; float sum_kevents = 0.0; events = userspace_events = 0; - memcpy(tmp, sym_table, sizeof(sym_table[0])*sym_table_count); - qsort(tmp, sym_table_count, sizeof(tmp[0]), compare); - for (i = 0; i < sym_table_count && tmp[i].count[0]; i++) - sum_kevents += tmp[i].count[0]; + /* Iterate over symbol table and copy/tally/decay active symbols. */ + for (i = 0, active_count = 0; i < sym_table_count; i++) { + if (sym_table[i].count[0]) { + tmp[active_count++] = sym_table[i]; + sum_kevents += sym_table[i].count[0]; + + for (j = 0; j < nr_counters; j++) + sym_table[i].count[j] = zero ? 0 : sym_table[i].count[j] * 7 / 8; + } + } + + qsort(tmp, active_count + 1, sizeof(tmp[0]), compare); write(1, CONSOLE_CLEAR, strlen(CONSOLE_CLEAR)); @@ -433,29 +441,23 @@ static void print_sym_table(void) " ______ ______ _____ ________________ _______________\n\n" ); - for (i = 0, printed = 0; i < sym_table_count; i++) { + for (i = 0, printed = 0; i < active_count; i++) { float pcnt; - int count; - if (printed <= 18 && tmp[i].count[0] >= count_filter) { - pcnt = 100.0 - (100.0*((sum_kevents-tmp[i].count[0])/sum_kevents)); - - if (nr_counters == 1) - printf("%19.2f - %4.1f%% - %016llx : %s\n", - sym_weight(tmp + i), - pcnt, tmp[i].addr, tmp[i].sym); - else - printf("%8.1f %10ld - %4.1f%% - %016llx : %s\n", - sym_weight(tmp + i), - tmp[i].count[0], - pcnt, tmp[i].addr, tmp[i].sym); - printed++; - } - /* - * Add decay to the counts: - */ - for (count = 0; count < nr_counters; count++) - sym_table[i].count[count] = zero ? 0 : sym_table[i].count[count] * 7 / 8; + if (++printed > 18 || tmp[i].count[0] < count_filter) + break; + + pcnt = 100.0 - (100.0*((sum_kevents-tmp[i].count[0])/sum_kevents)); + + if (nr_counters == 1) + printf("%19.2f - %4.1f%% - %016llx : %s\n", + sym_weight(tmp + i), + pcnt, tmp[i].addr, tmp[i].sym); + else + printf("%8.1f %10ld - %4.1f%% - %016llx : %s\n", + sym_weight(tmp + i), + tmp[i].count[0], + pcnt, tmp[i].addr, tmp[i].sym); } if (sym_filter_entry)