Messages in this thread | | | From | Rasmus Villemoes <> | Date | Thu, 10 Jan 2019 22:12:52 +0100 | Subject | Re: [PATCH] perf: replace automatic const char[] variables by statics |
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On Sun, 4 Nov 2018 at 20:26, Jiri Olsa <jolsa@redhat.com> wrote: > > On Sat, Nov 03, 2018 at 12:06:23AM +0100, Rasmus Villemoes wrote: > > 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. > > > > Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> > > sounds good > > Acked-by: Jiri Olsa <jolsa@kernel.org> > > thanks, > jirka > > > --- > > 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 f3aa9d02a5ab..ab6a89e5393c 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 257c9c18cb7e..ff615c624784 100644 > > --- a/tools/perf/builtin-report.c > > +++ b/tools/perf/builtin-report.c > > @@ -955,9 +955,9 @@ 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 [<options>]", > > 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 a96f62ca984a..eab9dc025b3a 100644 > > --- a/tools/perf/ui/browsers/hists.c > > +++ b/tools/perf/ui/browsers/hists.c > > @@ -2737,7 +2737,7 @@ 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" > > @@ -2745,7 +2745,7 @@ 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" > > -- > > 2.19.1.6.gbde171bbf5 > >
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