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 <linux@rasmusvillemoes.dk>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20181102230624.20064-1-linux@rasmusvillemoes.dk
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
index d340d2e..f286349 100644 (file)
--- 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 b63bca4..088705c 100644 (file)
--- 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 4958095..794a0de 100644 (file)
--- 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 [<options>]",

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index cbf39da..2e0f0c6 100644 (file)
--- 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 d754921..5aeb663 100644 (file)
--- 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 ffac1d5..b32f505 100644 (file)
--- 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"