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[5.186.114.252]) by smtp.gmail.com with ESMTPSA id d6-v6sm103540edl.61.2018.11.02.16.06.52 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 02 Nov 2018 16:06:53 -0700 (PDT) From: Rasmus Villemoes To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Alexander Shishkin , Jiri Olsa , Namhyung Kim Cc: Rasmus Villemoes , linux-kernel@vger.kernel.org Subject: [PATCH] perf: replace automatic const char[] variables by statics Date: Sat, 3 Nov 2018 00:06:23 +0100 Message-Id: <20181102230624.20064-1-linux@rasmusvillemoes.dk> X-Mailer: git-send-email 2.19.1.6.gbde171bbf5 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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 []", 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