From dde4e732a5b02fa5599c2c0e6c48a0c11789afc4 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Thu, 11 Jul 2019 11:19:21 -0700 Subject: [PATCH] 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 Signed-off-by: Andi Kleen Cc: Jiri Olsa Link: http://lkml.kernel.org/r/20190711181922.18765-2-andi@firstfloor.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-script.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c index 8f24865596af..0140ddb8dd0b 100644 --- a/tools/perf/builtin-script.c +++ b/tools/perf/builtin-script.c @@ -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);