From 49b8e2beceda79ae25938faf68fad0ad62534852 Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Sat, 3 Nov 2018 00:06:23 +0100 Subject: [PATCH] perf tools: Replace automatic const char[] variables by statics An automatic const char[] variable gets initialized at runtime, just like any other automatic variable. For long strings, that uses a lot of stack and wastes time building the string; e.g. for the "No %s allocation events..." case one has: 444516: 48 b8 4e 6f 20 25 73 20 61 6c movabs $0x6c61207325206f4e,%rax # "No %s al" ... 444674: 48 89 45 80 mov %rax,-0x80(%rbp) 444678: 48 b8 6c 6f 63 61 74 69 6f 6e movabs $0x6e6f697461636f6c,%rax # "location" 444682: 48 89 45 88 mov %rax,-0x78(%rbp) 444686: 48 b8 20 65 76 65 6e 74 73 20 movabs $0x2073746e65766520,%rax # " events " 444690: 66 44 89 55 c4 mov %r10w,-0x3c(%rbp) 444695: 48 89 45 90 mov %rax,-0x70(%rbp) 444699: 48 b8 66 6f 75 6e 64 2e 20 20 movabs $0x20202e646e756f66,%rax Make them all static so that the compiler just references objects in .rodata. Committer testing: Ok, using dwarves's codiff tool: $ codiff --functions /tmp/perf.before ~/bin/perf builtin-sched.c: cmd_sched | -48 1 function changed, 48 bytes removed, diff: -48 builtin-report.c: cmd_report | -32 1 function changed, 32 bytes removed, diff: -32 builtin-kmem.c: cmd_kmem | -64 build_alloc_func_list | -50 2 functions changed, 114 bytes removed, diff: -114 builtin-c2c.c: perf_c2c__report | -390 1 function changed, 390 bytes removed, diff: -390 ui/browsers/header.c: tui__header_window | -104 1 function changed, 104 bytes removed, diff: -104 /home/acme/bin/perf: 9 functions changed, 688 bytes removed, diff: -688 Signed-off-by: Rasmus Villemoes Acked-by: Jiri Olsa Tested-by: Arnaldo Carvalho de Melo Cc: Alexander Shishkin Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20181102230624.20064-1-linux@rasmusvillemoes.dk Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-c2c.c | 4 ++-- tools/perf/builtin-kmem.c | 4 ++-- tools/perf/builtin-report.c | 6 +++--- tools/perf/builtin-sched.c | 2 +- tools/perf/ui/browsers/header.c | 2 +- tools/perf/ui/browsers/hists.c | 4 ++-- 6 files changed, 11 insertions(+), 11 deletions(-) diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c index d340d2e42776..f2863496dede 100644 --- a/tools/perf/builtin-c2c.c +++ b/tools/perf/builtin-c2c.c @@ -2343,7 +2343,7 @@ static int perf_c2c__browse_cacheline(struct hist_entry *he) struct c2c_cacheline_browser *cl_browser; struct hist_browser *browser; int key = -1; - const char help[] = + static const char help[] = " ENTER Toggle callchains (if present) \n" " n Toggle Node details info \n" " s Toggle full length of symbol and source line columns \n" @@ -2424,7 +2424,7 @@ static int perf_c2c__hists_browse(struct hists *hists) { struct hist_browser *browser; int key = -1; - const char help[] = + static const char help[] = " d Display cacheline details \n" " ENTER Toggle callchains (if present) \n" " q Quit \n"; diff --git a/tools/perf/builtin-kmem.c b/tools/perf/builtin-kmem.c index b63bca4b0c2a..088705c167bf 100644 --- a/tools/perf/builtin-kmem.c +++ b/tools/perf/builtin-kmem.c @@ -334,7 +334,7 @@ static int build_alloc_func_list(void) struct alloc_func *func; struct machine *machine = &kmem_session->machines.host; regex_t alloc_func_regex; - const char pattern[] = "^_?_?(alloc|get_free|get_zeroed)_pages?"; + static const char pattern[] = "^_?_?(alloc|get_free|get_zeroed)_pages?"; ret = regcomp(&alloc_func_regex, pattern, REG_EXTENDED); if (ret) { @@ -1924,7 +1924,7 @@ int cmd_kmem(int argc, const char **argv) NULL }; struct perf_session *session; - const char errmsg[] = "No %s allocation events found. Have you run 'perf kmem record --%s'?\n"; + static const char errmsg[] = "No %s allocation events found. Have you run 'perf kmem record --%s'?\n"; int ret = perf_config(kmem_config, NULL); if (ret) diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c index 4958095be4fc..794a0de5ac1d 100644 --- a/tools/perf/builtin-report.c +++ b/tools/perf/builtin-report.c @@ -956,9 +956,9 @@ int cmd_report(int argc, const char **argv) int branch_mode = -1; bool branch_call_mode = false; #define CALLCHAIN_DEFAULT_OPT "graph,0.5,caller,function,percent" - const char report_callchain_help[] = "Display call graph (stack chain/backtrace):\n\n" - CALLCHAIN_REPORT_HELP - "\n\t\t\t\tDefault: " CALLCHAIN_DEFAULT_OPT; + static const char report_callchain_help[] = "Display call graph (stack chain/backtrace):\n\n" + CALLCHAIN_REPORT_HELP + "\n\t\t\t\tDefault: " CALLCHAIN_DEFAULT_OPT; char callchain_default_opt[] = CALLCHAIN_DEFAULT_OPT; const char * const report_usage[] = { "perf report []", diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c index cbf39dab19c1..2e0f0c65964a 100644 --- a/tools/perf/builtin-sched.c +++ b/tools/perf/builtin-sched.c @@ -3336,7 +3336,7 @@ static int __cmd_record(int argc, const char **argv) int cmd_sched(int argc, const char **argv) { - const char default_sort_order[] = "avg, max, switch, runtime"; + static const char default_sort_order[] = "avg, max, switch, runtime"; struct perf_sched sched = { .tool = { .sample = perf_sched__process_tracepoint_sample, diff --git a/tools/perf/ui/browsers/header.c b/tools/perf/ui/browsers/header.c index d75492189acb..5aeb663dd184 100644 --- a/tools/perf/ui/browsers/header.c +++ b/tools/perf/ui/browsers/header.c @@ -35,7 +35,7 @@ static int list_menu__run(struct ui_browser *menu) { int key; unsigned long offset; - const char help[] = + static const char help[] = "h/?/F1 Show this window\n" "UP/DOWN/PGUP\n" "PGDN/SPACE\n" diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c index ffac1d54a3d4..b32f505a7608 100644 --- a/tools/perf/ui/browsers/hists.c +++ b/tools/perf/ui/browsers/hists.c @@ -2748,7 +2748,7 @@ static int perf_evsel__hists_browse(struct perf_evsel *evsel, int nr_events, "S Zoom into current Processor Socket\n" \ /* help messages are sorted by lexical order of the hotkey */ - const char report_help[] = HIST_BROWSER_HELP_COMMON + static const char report_help[] = HIST_BROWSER_HELP_COMMON "i Show header information\n" "P Print histograms to perf.hist.N\n" "r Run available scripts\n" @@ -2756,7 +2756,7 @@ static int perf_evsel__hists_browse(struct perf_evsel *evsel, int nr_events, "t Zoom into current Thread\n" "V Verbose (DSO names in callchains, etc)\n" "/ Filter symbol by name"; - const char top_help[] = HIST_BROWSER_HELP_COMMON + static const char top_help[] = HIST_BROWSER_HELP_COMMON "P Print histograms to perf.hist.N\n" "t Zoom into current Thread\n" "V Verbose (DSO names in callchains, etc)\n"