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@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: John Kacur <jkacur@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20090526222057.GI4424@ghostprotocols.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Arnaldo Carvalho de Melo
Ingo Molnar
parent
3a4b8cc70b
commit
d8d1656ee1
@ -348,6 +348,39 @@ void dsos__fprintf(FILE *fp)
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dso__fprintf(pos, fp);
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}
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static int hex(char ch)
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{
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if ((ch >= '0') && (ch <= '9'))
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return ch - '0';
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if ((ch >= 'a') && (ch <= 'f'))
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return ch - 'a' + 10;
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if ((ch >= 'A') && (ch <= 'F'))
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return ch - 'A' + 10;
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return -1;
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}
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/*
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* While we find nice hex chars, build a long_val.
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* Return number of chars processed.
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*/
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int hex2long(char *ptr, unsigned long *long_val)
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{
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const char *p = ptr;
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*long_val = 0;
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while (*p) {
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const int hex_val = hex(*p);
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if (hex_val < 0)
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break;
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*long_val = (*long_val << 4) | hex_val;
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p++;
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}
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return p - ptr;
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}
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static int load_kallsyms(void)
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{
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kernel_dso = dso__new("[kernel]");
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@ -363,26 +396,30 @@ static int load_kallsyms(void)
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size_t n;
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while (!feof(file)) {
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unsigned long long start;
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char c, symbf[4096];
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if (getline(&line, &n, file) < 0)
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unsigned long start;
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int line_len = getline(&line, &n, file);
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if (line_len < 0)
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break;
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if (!line)
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goto out_delete_dso;
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if (sscanf(line, "%llx %c %s", &start, &c, symbf) == 3) {
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/*
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* Well fix up the end later, when we have all sorted.
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*/
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struct symbol *sym = symbol__new(start, 0xdead, symbf);
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line[--line_len] = '\0'; /* \n */
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if (sym == NULL)
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goto out_delete_dso;
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int len = hex2long(line, &start);
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len += 3; /* ' t ' */
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if (len >= line_len)
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continue;
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/*
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* Well fix up the end later, when we have all sorted.
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*/
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struct symbol *sym = symbol__new(start, 0xdead, line + len);
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dso__insert_symbol(kernel_dso, sym);
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}
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if (sym == NULL)
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goto out_delete_dso;
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dso__insert_symbol(kernel_dso, sym);
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}
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/*
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