Re: [PATCH] perf script: Add 'brstackinsnlen' for branch stacks
From: Arnaldo Carvalho de Melo
Date: Tue Mar 22 2022 - 17:01:38 EST
Em Mon, Mar 21, 2022 at 07:00:12AM -0700, kan.liang@xxxxxxxxxxxxxxx escreveu:
> From: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
>
> When analyzing with the perf script, it's useful to understand the
> captured instruction and the next sequential instruction. To calculate
> the address of the next sequential instruction, the length of the
> captured instruction is required. For example, you can’t know the next
> sequential instruction after an unconditional branch unless you
> calculate that based on its length.
>
> For branch stacks, the current perf script only prints the instruction
> bytes with 'brstackinsn', but lack of instruction length.
>
> Add 'brstackinsnlen' to print the instruction length.
>
> $perf script -F ip,brstackinsn,brstackinsnlen --xed
> 7fa555be8f75
> _start:
> 00007fa555be8090 mov %rsp, %rdi ilen: 3
> 00007fa555be8093 callq 0x7fa555be8ea0 ilen: 5 # PRED
> 102 cycles [102] 0.02 IPC
> _dl_start+38:
> 00007fa555be8ec6 movq %rdx,0x227853(%rip) ilen: 7
> 00007fa555be8ecd leaq 0x227f94(%rip),%rdx ilen: 7
>
> Signed-off-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
You forgot to update tools/perf/Documentation/perf-script.txt, I added
it this time.
Thanks, applied.
- Arnaldo
> ---
> tools/perf/builtin-script.c | 44 ++++++++++++++++++++++++++++++++------------
> 1 file changed, 32 insertions(+), 12 deletions(-)
>
> diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
> index fa478dd..5a7b2b0 100644
> --- a/tools/perf/builtin-script.c
> +++ b/tools/perf/builtin-script.c
> @@ -124,6 +124,7 @@ enum perf_output_field {
> PERF_OUTPUT_DATA_PAGE_SIZE = 1ULL << 33,
> PERF_OUTPUT_CODE_PAGE_SIZE = 1ULL << 34,
> PERF_OUTPUT_INS_LAT = 1ULL << 35,
> + PERF_OUTPUT_BRSTACKINSNLEN = 1ULL << 36,
> };
>
> struct perf_script {
> @@ -191,6 +192,7 @@ struct output_option {
> {.str = "data_page_size", .field = PERF_OUTPUT_DATA_PAGE_SIZE},
> {.str = "code_page_size", .field = PERF_OUTPUT_CODE_PAGE_SIZE},
> {.str = "ins_lat", .field = PERF_OUTPUT_INS_LAT},
> + {.str = "brstackinsnlen", .field = PERF_OUTPUT_BRSTACKINSNLEN},
> };
>
> enum {
> @@ -488,7 +490,7 @@ static int evsel__check_attr(struct evsel *evsel, struct perf_session *session)
> "selected. Hence, no address to lookup the source line number.\n");
> return -EINVAL;
> }
> - if (PRINT_FIELD(BRSTACKINSN) && !allow_user_set &&
> + if ((PRINT_FIELD(BRSTACKINSN) || PRINT_FIELD(BRSTACKINSNLEN)) && !allow_user_set &&
> !(evlist__combined_branch_type(session->evlist) & PERF_SAMPLE_BRANCH_ANY)) {
> pr_err("Display of branch stack assembler requested, but non all-branch filter set\n"
> "Hint: run 'perf record -b ...'\n");
> @@ -1122,10 +1124,17 @@ static int print_srccode(struct thread *thread, u8 cpumode, uint64_t addr)
>
> static int ip__fprintf_jump(uint64_t ip, struct branch_entry *en,
> struct perf_insn *x, u8 *inbuf, int len,
> - int insn, FILE *fp, int *total_cycles)
> + int insn, FILE *fp, int *total_cycles,
> + struct perf_event_attr *attr)
> {
> - int printed = fprintf(fp, "\t%016" PRIx64 "\t%-30s\t#%s%s%s%s", ip,
> - dump_insn(x, ip, inbuf, len, NULL),
> + int ilen = 0;
> + int printed = fprintf(fp, "\t%016" PRIx64 "\t%-30s\t", ip,
> + dump_insn(x, ip, inbuf, len, &ilen));
> +
> + if (PRINT_FIELD(BRSTACKINSNLEN))
> + printed += fprintf(fp, "ilen: %d\t", ilen);
> +
> + printed += fprintf(fp, "#%s%s%s%s",
> en->flags.predicted ? " PRED" : "",
> en->flags.mispred ? " MISPRED" : "",
> en->flags.in_tx ? " INTX" : "",
> @@ -1211,7 +1220,8 @@ static int perf_sample__fprintf_brstackinsn(struct perf_sample *sample,
> printed += ip__fprintf_sym(entries[nr - 1].from, thread,
> x.cpumode, x.cpu, &lastsym, attr, fp);
> printed += ip__fprintf_jump(entries[nr - 1].from, &entries[nr - 1],
> - &x, buffer, len, 0, fp, &total_cycles);
> + &x, buffer, len, 0, fp, &total_cycles,
> + attr);
> if (PRINT_FIELD(SRCCODE))
> printed += print_srccode(thread, x.cpumode, entries[nr - 1].from);
> }
> @@ -1242,14 +1252,17 @@ 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, &entries[i], &x, buffer + off, len - off, ++insn, fp,
> - &total_cycles);
> + &total_cycles, attr);
> if (PRINT_FIELD(SRCCODE))
> printed += print_srccode(thread, x.cpumode, ip);
> break;
> } else {
> ilen = 0;
> - printed += fprintf(fp, "\t%016" PRIx64 "\t%s\n", ip,
> + printed += fprintf(fp, "\t%016" PRIx64 "\t%s", ip,
> dump_insn(&x, ip, buffer + off, len - off, &ilen));
> + if (PRINT_FIELD(BRSTACKINSNLEN))
> + printed += fprintf(fp, "\tilen: %d", ilen);
> + printed += fprintf(fp, "\n");
> if (ilen == 0)
> break;
> if (PRINT_FIELD(SRCCODE))
> @@ -1292,16 +1305,23 @@ static int perf_sample__fprintf_brstackinsn(struct perf_sample *sample,
> machine, thread, &x.is64bit, &x.cpumode, false);
> if (len <= 0)
> goto out;
> - printed += fprintf(fp, "\t%016" PRIx64 "\t%s\n", sample->ip,
> - dump_insn(&x, sample->ip, buffer, len, NULL));
> + ilen = 0;
> + printed += fprintf(fp, "\t%016" PRIx64 "\t%s", sample->ip,
> + dump_insn(&x, sample->ip, buffer, len, &ilen));
> + if (PRINT_FIELD(BRSTACKINSNLEN))
> + printed += fprintf(fp, "\tilen: %d", ilen);
> + printed += fprintf(fp, "\n");
> if (PRINT_FIELD(SRCCODE))
> print_srccode(thread, x.cpumode, sample->ip);
> goto out;
> }
> for (off = 0; off <= end - start; off += ilen) {
> ilen = 0;
> - printed += fprintf(fp, "\t%016" PRIx64 "\t%s\n", start + off,
> + printed += fprintf(fp, "\t%016" PRIx64 "\t%s", start + off,
> dump_insn(&x, start + off, buffer + off, len - off, &ilen));
> + if (PRINT_FIELD(BRSTACKINSNLEN))
> + printed += fprintf(fp, "\tilen: %d", ilen);
> + printed += fprintf(fp, "\n");
> if (ilen == 0)
> break;
> if (arch_is_branch(buffer + off, len - off, x.is64bit) && start + off != sample->ip) {
> @@ -1459,7 +1479,7 @@ static int perf_sample__fprintf_insn(struct perf_sample *sample,
> for (i = 0; i < sample->insn_len; i++)
> printed += fprintf(fp, " %02x", (unsigned char)sample->insn[i]);
> }
> - if (PRINT_FIELD(BRSTACKINSN))
> + if (PRINT_FIELD(BRSTACKINSN) || PRINT_FIELD(BRSTACKINSNLEN))
> printed += perf_sample__fprintf_brstackinsn(sample, thread, attr, machine, fp);
>
> return printed;
> @@ -3716,7 +3736,7 @@ int cmd_script(int argc, const char **argv)
> "Valid types: hw,sw,trace,raw,synth. "
> "Fields: comm,tid,pid,time,cpu,event,trace,ip,sym,dso,"
> "addr,symoff,srcline,period,iregs,uregs,brstack,"
> - "brstacksym,flags,bpf-output,brstackinsn,brstackoff,"
> + "brstacksym,flags,bpf-output,brstackinsn,brstackinsnlen,brstackoff,"
> "callindent,insn,insnlen,synth,phys_addr,metric,misc,ipc,tod,"
> "data_page_size,code_page_size,ins_lat",
> parse_output_fields),
> --
> 2.7.4
--
- Arnaldo