[tip:perfcounters/core] perf report: Use hex2long instead of sscanf
From: tip-bot for Arnaldo Carvalho de Melo
Date: Wed May 27 2009 - 03:18:01 EST
Commit-ID: d8d1656ee15d3085e0085a87e70f9093a0a102c5
Gitweb: http://git.kernel.org/tip/d8d1656ee15d3085e0085a87e70f9093a0a102c5
Author: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Tue, 26 May 2009 19:20:57 -0300
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Wed, 27 May 2009 09:10:35 +0200
perf report: Use hex2long instead of sscanf
Before:
[acme@emilia ~]$ perf record -o perf_report.perf perf stat perf report > /dev/null
Performance counter stats for 'perf':
245.414985 task clock ticks (msecs)
6 context switches (events)
6 CPU migrations (events)
2108 pagefaults (events)
37493013 CPU cycles (events) (scaled from 67.04%)
13576789 instructions (events) (scaled from 66.76%)
57931 cache references (events) (scaled from 21.96%)
12263 cache misses (events) (scaled from 21.98%)
Wall-clock time elapsed: 246.575587 msecs
[acme@emilia ~]$ perf report -i perf_report.perf | head
12.15 perf [.] 0x000000000005432a /lib64/libc-2.5.so: _IO_vfscanf_internal
9.38 perf [k] 0xffffffff8101b1d2 intel_pmu_enable_all
8.53 perf [.] 0x00000000000056b8 /home/acme/git/linux-2.6-tip/Documentation/perf_counter/perf: dso__insert_symbol
6.61 perf [.] 0x00000000000057cb /home/acme/git/linux-2.6-tip/Documentation/perf_counter/perf: dso__find_symbol
5.33 perf [k] 0xffffffff811ce082 number
4.69 perf [.] 0x0000000000034829 /lib64/libc-2.5.so: ____strtoull_l_internal
4.48 perf [.] 0x0000000000006505 /home/acme/git/linux-2.6-tip/Documentation/perf_counter/perf: thread__symbol_incnew
3.41 perf [.] 0x000000000000fce6 /home/acme/git/linux-2.6-tip/Documentation/perf_counter/perf: rb_insert_color
3.20 perf [k] 0xffffffff811cfc01 vsnprintf
2.99 perf [k] 0xffffffff811ce5e8 format_decode
After:
[acme@emilia ~]$ perf record -o perf_report.perf perf stat perf report > /dev/null
Performance counter stats for 'perf':
218.186805 task clock ticks (msecs)
4 context switches (events)
7 CPU migrations (events)
2133 pagefaults (events)
32735365 CPU cycles (events) (scaled from 67.04%)
11952309 instructions (events) (scaled from 66.26%)
50314 cache references (events) (scaled from 21.96%)
13228 cache misses (events) (scaled from 21.98%)
Wall-clock time elapsed: 218.810451 msecs
[acme@emilia ~]$ perf report -i perf_report.perf | head
10.68 perf [.] 0x000000000000578d /home/acme/git/linux-2.6-tip/Documentation/perf_counter/perf: dso__find_symbol
9.62 perf [.] 0x00000000000065f7 /home/acme/git/linux-2.6-tip/Documentation/perf_counter/perf: thread__symbol_incnew
9.40 perf [.] 0x00000000000056b4 /home/acme/git/linux-2.6-tip/Documentation/perf_counter/perf: dso__insert_symbol
9.19 perf [k] 0xffffffff8101b1d2 intel_pmu_enable_all
5.13 perf [.] 0x0000000000005ec7 /home/acme/git/linux-2.6-tip/Documentation/perf_counter/perf: hex2long
4.49 perf [k] 0xffffffff81083808 kallsyms_expand_symbol
3.85 perf [k] 0xffffffff811ce2c1 number
3.63 perf [.] 0x0000000000005e81 /home/acme/git/linux-2.6-tip/Documentation/perf_counter/perf: hex
2.99 perf [.] 0x000000000000fd5b /home/acme/git/linux-2.6-tip/Documentation/perf_counter/perf: rb_insert_color
2.99 perf [k] 0xffffffff811cf251 string
[acme@emilia ~]$
[ Impact: optimization ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Corey Ashford <cjashfor@xxxxxxxxxxxxxxxxxx>
Cc: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: John Kacur <jkacur@xxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
LKML-Reference: <20090526222057.GI4424@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
Documentation/perf_counter/builtin-report.c | 63 +++++++++++++++++++++------
1 files changed, 50 insertions(+), 13 deletions(-)
diff --git a/Documentation/perf_counter/builtin-report.c b/Documentation/perf_counter/builtin-report.c
index a4c6ffa..c517483 100644
--- a/Documentation/perf_counter/builtin-report.c
+++ b/Documentation/perf_counter/builtin-report.c
@@ -348,6 +348,39 @@ void dsos__fprintf(FILE *fp)
dso__fprintf(pos, fp);
}
+static int hex(char ch)
+{
+ if ((ch >= '0') && (ch <= '9'))
+ return ch - '0';
+ if ((ch >= 'a') && (ch <= 'f'))
+ return ch - 'a' + 10;
+ if ((ch >= 'A') && (ch <= 'F'))
+ return ch - 'A' + 10;
+ return -1;
+}
+
+/*
+ * While we find nice hex chars, build a long_val.
+ * Return number of chars processed.
+ */
+int hex2long(char *ptr, unsigned long *long_val)
+{
+ const char *p = ptr;
+ *long_val = 0;
+
+ while (*p) {
+ const int hex_val = hex(*p);
+
+ if (hex_val < 0)
+ break;
+
+ *long_val = (*long_val << 4) | hex_val;
+ p++;
+ }
+
+ return p - ptr;
+}
+
static int load_kallsyms(void)
{
kernel_dso = dso__new("[kernel]");
@@ -363,26 +396,30 @@ static int load_kallsyms(void)
size_t n;
while (!feof(file)) {
- unsigned long long start;
- char c, symbf[4096];
-
- if (getline(&line, &n, file) < 0)
+ unsigned long start;
+ int line_len = getline(&line, &n, file);
+ if (line_len < 0)
break;
if (!line)
goto out_delete_dso;
- if (sscanf(line, "%llx %c %s", &start, &c, symbf) == 3) {
- /*
- * Well fix up the end later, when we have all sorted.
- */
- struct symbol *sym = symbol__new(start, 0xdead, symbf);
+ line[--line_len] = '\0'; /* \n */
+
+ int len = hex2long(line, &start);
+
+ len += 3; /* ' t ' */
+ if (len >= line_len)
+ continue;
+ /*
+ * Well fix up the end later, when we have all sorted.
+ */
+ struct symbol *sym = symbol__new(start, 0xdead, line + len);
- if (sym == NULL)
- goto out_delete_dso;
+ if (sym == NULL)
+ goto out_delete_dso;
- dso__insert_symbol(kernel_dso, sym);
- }
+ dso__insert_symbol(kernel_dso, sym);
}
/*
--
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