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perf script: Fix off by one in brstackinsn IPC computation 

When we hit the end of a program block, need to count the last
instruction too for the IPC computation. This caused large errors for
small blocks.

  % perf script -b ls / > /dev/null

Before:

  % perf script -F +brstackinsn --xed
  ...
        00007f94c9ac70d8                        jz 0x7f94c9ac70e3                       # PRED 3 cycles [36] 4.33 IPC
        00007f94c9ac70e3                        testb  $0x20, 0x31d(%rbx)
        00007f94c9ac70ea                        jnz 0x7f94c9ac70b0
        00007f94c9ac70ec                        testb  $0x8, 0x205ad(%rip)
        00007f94c9ac70f3                        jz 0x7f94c9ac6ff0               # PRED 1 cycles [37] 3.00 IPC

After:

  % perf script -F +brstackinsn --xed
  ...
        00007f94c9ac70d8                        jz 0x7f94c9ac70e3                       # PRED 3 cycles [15] 4.67 IPC
        00007f94c9ac70e3                        testb  $0x20, 0x31d(%rbx)
        00007f94c9ac70ea                        jnz 0x7f94c9ac70b0
        00007f94c9ac70ec                        testb  $0x8, 0x205ad(%rip)
        00007f94c9ac70f3                        jz 0x7f94c9ac6ff0               # PRED 1 cycles [16] 4.00 IPC

Suggested-by: Denis Bakhvalov <denis.bakhvalov@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/20190711181922.18765-2-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Andi Kleen 2019-07-11 11:19:21 -07:00 committed by Arnaldo Carvalho de Melo
parent 7db7218a7e
commit dde4e732a5
1 changed files with 1 additions and 1 deletions
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2
tools/perf/builtin-script.c
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@ -1059,7 +1059,7 @@ static int perf_sample__fprintf_brstackinsn(struct perf_sample *sample,
printed += ip__fprintf_sym(ip, thread, x.cpumode, x.cpu, &lastsym, attr, fp);
if (ip == end) {
printed += ip__fprintf_jump(ip, &br->entries[i], &x, buffer + off, len - off, insn, fp,
printed += ip__fprintf_jump(ip, &br->entries[i], &x, buffer + off, len - off, ++insn, fp,
&total_cycles);
if (PRINT_FIELD(SRCCODE))
printed += print_srccode(thread, x.cpumode, ip);