Re: [PATCH RFC] perf: Go back to by-hand proc mmap parsing and kill timeout
From: Arnaldo Carvalho de Melo
Date: Wed Oct 31 2018 - 12:44:23 EST
Em Wed, Oct 31, 2018 at 12:19:10PM -0400, Liang, Kan escreveu:
>
>
> On 10/31/2018 9:21 AM, Arnaldo Carvalho de Melo wrote:
> > Em Tue, Oct 30, 2018 at 10:54:16PM -0700, David Miller escreveu:
> > >
> > > This goes back to by-hand parsing of the proc mmap file, and removes
> > > the timeout.
> > >
> > > In my measurements this makes the parsing about twice as fast.
> > >
> > > Profiling thread synthesizing shows that most of the time is spent in
> > > the sscanf() call.
> > >
>
> I did some performance test to evaluate the time cost on proc mmap parsing
> with different options/patches.
>
> The benchmark I used is case-small-allocs from vm-scalability.
>
> I did the test on two machines.
> M1: Skylake server (224 CPUs)
> M2: Knights Landing (272 CPUs)
>
> With three different options for perf top.
> P1: baseline test. No David's patch. "perf top"
> P2: No David's patch. Set a big timeout. The proc map processing will not be
> truncated. "perf top --proc-map-timeout 10000"
> P3: With David's patch. "perf top"
>
> The elapsed time is the time cost for synthesize_threads.
>
> On M1
> Elapsed time (Seconds)
> P1 ~6
> P2 8-24*
> P3 6-11*
> *The time cost is not stable. I did several tests. Here lists a range of the
> results.
>
> On M2
> Elapsed time (Seconds)
> P1 41
> P2 282
> P3 176
> I only did test one time.
>
> The conclusion,
> - David's patch significantly improve the time cost of proc mmap parsing.
> - On some platform, especially Knights Landing, the time cost is still huge
> even with David's patch.
> - I think timeout is still needed. We have to give user warning/hints if the
> processing time is too long. For example, with P3 on M2, I can only see a
> black screen during the ~3 mins processing time.
That is why I mentioned that:
> I'm going to split this patch into two, one that makes it go back to
> by-hand proc mmap parsing, and the other killing the mmap-timeout.
I.e. the improvement is welcome, the removal of the timeout is a
separate issue :-)
- Arnaldo
> Thanks,
> Kan
>
> > > Processing samples is critical for perf top and perf record -a startup
> > > performance, and perf's ability to keep up with high sample rates.
> >
> > I'm going to split this patch into two, one that makes it go back to
> > by-hand proc mmap parsing, and the other killing the mmap-timeout.
> >
> > Thanks,
> >
> > - Arnaldo
> > > Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
> > >
> > > diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c
> > > index 2b1ef704169f..d4b5177c3c22 100644
> > > --- a/tools/perf/builtin-kvm.c
> > > +++ b/tools/perf/builtin-kvm.c
> > > @@ -1364,8 +1364,6 @@ static int kvm_events_live(struct perf_kvm_stat *kvm,
> > > "show events other than"
> > > " HLT (x86 only) or Wait state (s390 only)"
> > > " that take longer than duration usecs"),
> > > - OPT_UINTEGER(0, "proc-map-timeout", &kvm->opts.proc_map_timeout,
> > > - "per thread proc mmap processing timeout in ms"),
> > > OPT_END()
> > > };
> > > const char * const live_usage[] = {
> > > @@ -1394,7 +1392,6 @@ static int kvm_events_live(struct perf_kvm_stat *kvm,
> > > kvm->opts.target.uses_mmap = false;
> > > kvm->opts.target.uid_str = NULL;
> > > kvm->opts.target.uid = UINT_MAX;
> > > - kvm->opts.proc_map_timeout = 500;
> > > symbol__init(NULL);
> > > disable_buildid_cache();
> > > @@ -1453,8 +1450,7 @@ static int kvm_events_live(struct perf_kvm_stat *kvm,
> > > perf_session__set_id_hdr_size(kvm->session);
> > > ordered_events__set_copy_on_queue(&kvm->session->ordered_events, true);
> > > machine__synthesize_threads(&kvm->session->machines.host, &kvm->opts.target,
> > > - kvm->evlist->threads, false,
> > > - kvm->opts.proc_map_timeout, 1);
> > > + kvm->evlist->threads, false, 1);
> > > err = kvm_live_open_events(kvm);
> > > if (err)
> > > goto out;
> > > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> > > index 0980dfe3396b..4259ea42a8ef 100644
> > > --- a/tools/perf/builtin-record.c
> > > +++ b/tools/perf/builtin-record.c
> > > @@ -633,8 +633,7 @@ static int record__synthesize_workload(struct record *rec, bool tail)
> > > err = perf_event__synthesize_thread_map(&rec->tool, thread_map,
> > > process_synthesized_event,
> > > &rec->session->machines.host,
> > > - rec->opts.sample_address,
> > > - rec->opts.proc_map_timeout);
> > > + rec->opts.sample_address);
> > > thread_map__put(thread_map);
> > > return err;
> > > }
> > > @@ -848,8 +847,7 @@ static int record__synthesize(struct record *rec, bool tail)
> > > }
> > > err = __machine__synthesize_threads(machine, tool, &opts->target, rec->evlist->threads,
> > > - process_synthesized_event, opts->sample_address,
> > > - opts->proc_map_timeout, 1);
> > > + process_synthesized_event, opts->sample_address, 1);
> > > out:
> > > return err;
> > > }
> > > @@ -1521,7 +1519,6 @@ static struct record record = {
> > > .uses_mmap = true,
> > > .default_per_cpu = true,
> > > },
> > > - .proc_map_timeout = 500,
> > > },
> > > .tool = {
> > > .sample = process_sample_event,
> > > @@ -1651,8 +1648,6 @@ static struct option __record_options[] = {
> > > parse_clockid),
> > > OPT_STRING_OPTARG('S', "snapshot", &record.opts.auxtrace_snapshot_opts,
> > > "opts", "AUX area tracing Snapshot Mode", ""),
> > > - OPT_UINTEGER(0, "proc-map-timeout", &record.opts.proc_map_timeout,
> > > - "per thread proc mmap processing timeout in ms"),
> > > OPT_BOOLEAN(0, "namespaces", &record.opts.record_namespaces,
> > > "Record namespaces events"),
> > > OPT_BOOLEAN(0, "switch-events", &record.opts.record_switch_events,
> > > diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
> > > index d21d8751e749..4eec44d815bd 100644
> > > --- a/tools/perf/builtin-top.c
> > > +++ b/tools/perf/builtin-top.c
> > > @@ -1096,7 +1096,6 @@ static int __cmd_top(struct perf_top *top)
> > > machine__synthesize_threads(&top->session->machines.host, &opts->target,
> > > top->evlist->threads, false,
> > > - opts->proc_map_timeout,
> > > top->nr_threads_synthesize);
> > > if (top->nr_threads_synthesize > 1)
> > > @@ -1256,7 +1255,6 @@ int cmd_top(int argc, const char **argv)
> > > .target = {
> > > .uses_mmap = true,
> > > },
> > > - .proc_map_timeout = 500,
> > > .overwrite = 1,
> > > },
> > > .max_stack = sysctl__max_stack(),
> > > @@ -1360,8 +1358,6 @@ int cmd_top(int argc, const char **argv)
> > > OPT_STRING('w', "column-widths", &symbol_conf.col_width_list_str,
> > > "width[,width...]",
> > > "don't try to adjust column width, use these fixed values"),
> > > - OPT_UINTEGER(0, "proc-map-timeout", &opts->proc_map_timeout,
> > > - "per thread proc mmap processing timeout in ms"),
> > > OPT_CALLBACK_NOOPT('b', "branch-any", &opts->branch_stack,
> > > "branch any", "sample any taken branches",
> > > parse_branch_stack),
> > > diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
> > > index 90289f31dd87..0b68e0538107 100644
> > > --- a/tools/perf/builtin-trace.c
> > > +++ b/tools/perf/builtin-trace.c
> > > @@ -1240,8 +1240,7 @@ static int trace__symbols_init(struct trace *trace, struct perf_evlist *evlist)
> > > goto out;
> > > err = __machine__synthesize_threads(trace->host, &trace->tool, &trace->opts.target,
> > > - evlist->threads, trace__tool_process, false,
> > > - trace->opts.proc_map_timeout, 1);
> > > + evlist->threads, trace__tool_process, false, 1);
> > > out:
> > > if (err)
> > > symbol__exit();
> > > @@ -3242,7 +3241,6 @@ int cmd_trace(int argc, const char **argv)
> > > .user_interval = ULLONG_MAX,
> > > .no_buffering = true,
> > > .mmap_pages = UINT_MAX,
> > > - .proc_map_timeout = 500,
> > > },
> > > .output = stderr,
> > > .show_comm = true,
> > > @@ -3310,8 +3308,6 @@ int cmd_trace(int argc, const char **argv)
> > > "Default: kernel.perf_event_max_stack or " __stringify(PERF_MAX_STACK_DEPTH)),
> > > OPT_BOOLEAN(0, "print-sample", &trace.print_sample,
> > > "print the PERF_RECORD_SAMPLE PERF_SAMPLE_ info, for debugging"),
> > > - OPT_UINTEGER(0, "proc-map-timeout", &trace.opts.proc_map_timeout,
> > > - "per thread proc mmap processing timeout in ms"),
> > > OPT_CALLBACK('G', "cgroup", &trace, "name", "monitor event in cgroup name only",
> > > trace__parse_cgroups),
> > > OPT_UINTEGER('D', "delay", &trace.opts.initial_delay,
> > > diff --git a/tools/perf/perf.h b/tools/perf/perf.h
> > > index 21bf7f5a3cf5..0e2aafd8bb6e 100644
> > > --- a/tools/perf/perf.h
> > > +++ b/tools/perf/perf.h
> > > @@ -81,7 +81,6 @@ struct record_opts {
> > > unsigned initial_delay;
> > > bool use_clockid;
> > > clockid_t clockid;
> > > - unsigned int proc_map_timeout;
> > > };
> > > struct option;
> > > diff --git a/tools/perf/tests/code-reading.c b/tools/perf/tests/code-reading.c
> > > index 6b049f3f5cf4..dbf2c69944d2 100644
> > > --- a/tools/perf/tests/code-reading.c
> > > +++ b/tools/perf/tests/code-reading.c
> > > @@ -599,7 +599,7 @@ static int do_test_code_reading(bool try_kcore)
> > > }
> > > ret = perf_event__synthesize_thread_map(NULL, threads,
> > > - perf_event__process, machine, false, 500);
> > > + perf_event__process, machine, false);
> > > if (ret < 0) {
> > > pr_debug("perf_event__synthesize_thread_map failed\n");
> > > goto out_err;
> > > diff --git a/tools/perf/tests/dwarf-unwind.c b/tools/perf/tests/dwarf-unwind.c
> > > index 2f008067d989..7c8d2e422401 100644
> > > --- a/tools/perf/tests/dwarf-unwind.c
> > > +++ b/tools/perf/tests/dwarf-unwind.c
> > > @@ -34,7 +34,7 @@ static int init_live_machine(struct machine *machine)
> > > pid_t pid = getpid();
> > > return perf_event__synthesize_mmap_events(NULL, &event, pid, pid,
> > > - mmap_handler, machine, true, 500);
> > > + mmap_handler, machine, true);
> > > }
> > > /*
> > > diff --git a/tools/perf/tests/mmap-thread-lookup.c b/tools/perf/tests/mmap-thread-lookup.c
> > > index b1af2499a3c9..5ede9b561d32 100644
> > > --- a/tools/perf/tests/mmap-thread-lookup.c
> > > +++ b/tools/perf/tests/mmap-thread-lookup.c
> > > @@ -132,7 +132,7 @@ static int synth_all(struct machine *machine)
> > > {
> > > return perf_event__synthesize_threads(NULL,
> > > perf_event__process,
> > > - machine, 0, 500, 1);
> > > + machine, 0, 1);
> > > }
> > > static int synth_process(struct machine *machine)
> > > @@ -144,7 +144,7 @@ static int synth_process(struct machine *machine)
> > > err = perf_event__synthesize_thread_map(NULL, map,
> > > perf_event__process,
> > > - machine, 0, 500);
> > > + machine, 0);
> > > thread_map__put(map);
> > > return err;
> > > diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
> > > index bc646185f8d9..92b09b2ba6bf 100644
> > > --- a/tools/perf/util/event.c
> > > +++ b/tools/perf/util/event.c
> > > @@ -317,19 +317,39 @@ static int perf_event__synthesize_fork(struct perf_tool *tool,
> > > return 0;
> > > }
> > > +static int dec(char ch)
> > > +{
> > > + if ((ch >= '0') && (ch <= '9'))
> > > + return ch - '0';
> > > + return -1;
> > > +}
> > > +
> > > +static int dec2u64(const char *ptr, u64 *long_val)
> > > +{
> > > + const char *p = ptr;
> > > +
> > > + *long_val = 0;
> > > + while (*p) {
> > > + const int dec_val = dec(*p);
> > > +
> > > + if (dec_val < 0)
> > > + break;
> > > +
> > > + *long_val = (*long_val * 10) + dec_val;
> > > + p++;
> > > + }
> > > + return p - ptr;
> > > +}
> > > +
> > > int perf_event__synthesize_mmap_events(struct perf_tool *tool,
> > > union perf_event *event,
> > > pid_t pid, pid_t tgid,
> > > perf_event__handler_t process,
> > > struct machine *machine,
> > > - bool mmap_data,
> > > - unsigned int proc_map_timeout)
> > > + bool mmap_data)
> > > {
> > > char filename[PATH_MAX];
> > > FILE *fp;
> > > - unsigned long long t;
> > > - bool truncation = false;
> > > - unsigned long long timeout = proc_map_timeout * 1000000ULL;
> > > int rc = 0;
> > > const char *hugetlbfs_mnt = hugetlbfs__mountpoint();
> > > int hugetlbfs_mnt_len = hugetlbfs_mnt ? strlen(hugetlbfs_mnt) : 0;
> > > @@ -350,87 +370,99 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool,
> > > }
> > > event->header.type = PERF_RECORD_MMAP2;
> > > - t = rdclock();
> > > while (1) {
> > > - char bf[BUFSIZ];
> > > - char prot[5];
> > > - char execname[PATH_MAX];
> > > + char bf[BUFSIZ], *pbf = bf;
> > > char anonstr[] = "//anon";
> > > - unsigned int ino;
> > > + char *execname;
> > > size_t size;
> > > ssize_t n;
> > > + u64 tmp;
> > > if (fgets(bf, sizeof(bf), fp) == NULL)
> > > break;
> > > - if ((rdclock() - t) > timeout) {
> > > - pr_warning("Reading %s time out. "
> > > - "You may want to increase "
> > > - "the time limit by --proc-map-timeout\n",
> > > - filename);
> > > - truncation = true;
> > > - goto out;
> > > - }
> > > -
> > > - /* ensure null termination since stack will be reused. */
> > > - strcpy(execname, "");
> > > -
> > > /* 00400000-0040c000 r-xp 00000000 fd:01 41038 /bin/cat */
> > > - n = sscanf(bf, "%"PRIx64"-%"PRIx64" %s %"PRIx64" %x:%x %u %[^\n]\n",
> > > - &event->mmap2.start, &event->mmap2.len, prot,
> > > - &event->mmap2.pgoff, &event->mmap2.maj,
> > > - &event->mmap2.min,
> > > - &ino, execname);
> > > -
> > > - /*
> > > - * Anon maps don't have the execname.
> > > - */
> > > - if (n < 7)
> > > + n = hex2u64(pbf, &event->mmap2.start);
> > > + if (n < 0)
> > > continue;
> > > -
> > > - event->mmap2.ino = (u64)ino;
> > > -
> > > - /*
> > > - * Just like the kernel, see __perf_event_mmap in kernel/perf_event.c
> > > - */
> > > - if (machine__is_host(machine))
> > > - event->header.misc = PERF_RECORD_MISC_USER;
> > > - else
> > > - event->header.misc = PERF_RECORD_MISC_GUEST_USER;
> > > + pbf += n + 1;
> > > + n = hex2u64(pbf, &event->mmap2.len);
> > > + if (n < 0)
> > > + continue;
> > > + pbf += n + 1;
> > > /* map protection and flags bits */
> > > event->mmap2.prot = 0;
> > > event->mmap2.flags = 0;
> > > - if (prot[0] == 'r')
> > > + if (pbf[0] == 'r')
> > > event->mmap2.prot |= PROT_READ;
> > > - if (prot[1] == 'w')
> > > + if (pbf[1] == 'w')
> > > event->mmap2.prot |= PROT_WRITE;
> > > - if (prot[2] == 'x')
> > > + if (pbf[2] == 'x')
> > > event->mmap2.prot |= PROT_EXEC;
> > > - if (prot[3] == 's')
> > > + if (pbf[3] == 's')
> > > event->mmap2.flags |= MAP_SHARED;
> > > else
> > > event->mmap2.flags |= MAP_PRIVATE;
> > > - if (prot[2] != 'x') {
> > > - if (!mmap_data || prot[0] != 'r')
> > > + if (pbf[2] != 'x') {
> > > + if (!mmap_data || pbf[0] != 'r')
> > > continue;
> > > event->header.misc |= PERF_RECORD_MISC_MMAP_DATA;
> > > }
> > > -out:
> > > - if (truncation)
> > > - event->header.misc |= PERF_RECORD_MISC_PROC_MAP_PARSE_TIMEOUT;
> > > + pbf += 5;
> > > + n = hex2u64(pbf, &event->mmap2.pgoff);
> > > + if (n < 0)
> > > + continue;
> > > + pbf += n + 1;
> > > +
> > > + n = hex2u64(pbf, &tmp);
> > > + if (n < 0)
> > > + continue;
> > > + event->mmap2.maj = tmp;
> > > + pbf += n + 1;
> > > +
> > > + n = hex2u64(pbf, &tmp);
> > > + if (n < 0)
> > > + continue;
> > > + event->mmap2.min = tmp;
> > > + pbf += n + 1;
> > > - if (!strcmp(execname, ""))
> > > - strcpy(execname, anonstr);
> > > + n = dec2u64(pbf, &event->mmap2.ino);
> > > + if (n < 0)
> > > + continue;
> > > + pbf += n;
> > > +
> > > + execname = strchr(pbf, '/');
> > > + if (!execname)
> > > + execname = strchr(pbf, '[');
> > > +
> > > + /*
> > > + * Anon map, skip.
> > > + */
> > > + if (!execname)
> > > + continue;
> > > +
> > > + pbf = strchr(execname, '\n');
> > > + if (!pbf)
> > > + continue;
> > > + *pbf = '\0';
> > > +
> > > + /*
> > > + * Just like the kernel, see __perf_event_mmap in kernel/perf_event.c
> > > + */
> > > + if (machine__is_host(machine))
> > > + event->header.misc = PERF_RECORD_MISC_USER;
> > > + else
> > > + event->header.misc = PERF_RECORD_MISC_GUEST_USER;
> > > if (hugetlbfs_mnt_len &&
> > > !strncmp(execname, hugetlbfs_mnt, hugetlbfs_mnt_len)) {
> > > - strcpy(execname, anonstr);
> > > + execname = anonstr;
> > > event->mmap2.flags |= MAP_HUGETLB;
> > > }
> > > @@ -449,9 +481,6 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool,
> > > rc = -1;
> > > break;
> > > }
> > > -
> > > - if (truncation)
> > > - break;
> > > }
> > > fclose(fp);
> > > @@ -520,8 +549,7 @@ static int __event__synthesize_thread(union perf_event *comm_event,
> > > perf_event__handler_t process,
> > > struct perf_tool *tool,
> > > struct machine *machine,
> > > - bool mmap_data,
> > > - unsigned int proc_map_timeout)
> > > + bool mmap_data)
> > > {
> > > char filename[PATH_MAX];
> > > DIR *tasks;
> > > @@ -547,8 +575,7 @@ static int __event__synthesize_thread(union perf_event *comm_event,
> > > */
> > > if (pid == tgid &&
> > > perf_event__synthesize_mmap_events(tool, mmap_event, pid, tgid,
> > > - process, machine, mmap_data,
> > > - proc_map_timeout))
> > > + process, machine, mmap_data))
> > > return -1;
> > > return 0;
> > > @@ -597,7 +624,7 @@ static int __event__synthesize_thread(union perf_event *comm_event,
> > > if (_pid == pid) {
> > > /* process the parent's maps too */
> > > rc = perf_event__synthesize_mmap_events(tool, mmap_event, pid, tgid,
> > > - process, machine, mmap_data, proc_map_timeout);
> > > + process, machine, mmap_data);
> > > if (rc)
> > > break;
> > > }
> > > @@ -611,8 +638,7 @@ int perf_event__synthesize_thread_map(struct perf_tool *tool,
> > > struct thread_map *threads,
> > > perf_event__handler_t process,
> > > struct machine *machine,
> > > - bool mmap_data,
> > > - unsigned int proc_map_timeout)
> > > + bool mmap_data)
> > > {
> > > union perf_event *comm_event, *mmap_event, *fork_event;
> > > union perf_event *namespaces_event;
> > > @@ -642,7 +668,7 @@ int perf_event__synthesize_thread_map(struct perf_tool *tool,
> > > fork_event, namespaces_event,
> > > thread_map__pid(threads, thread), 0,
> > > process, tool, machine,
> > > - mmap_data, proc_map_timeout)) {
> > > + mmap_data)) {
> > > err = -1;
> > > break;
> > > }
> > > @@ -668,7 +694,7 @@ int perf_event__synthesize_thread_map(struct perf_tool *tool,
> > > fork_event, namespaces_event,
> > > comm_event->comm.pid, 0,
> > > process, tool, machine,
> > > - mmap_data, proc_map_timeout)) {
> > > + mmap_data)) {
> > > err = -1;
> > > break;
> > > }
> > > @@ -689,7 +715,6 @@ static int __perf_event__synthesize_threads(struct perf_tool *tool,
> > > perf_event__handler_t process,
> > > struct machine *machine,
> > > bool mmap_data,
> > > - unsigned int proc_map_timeout,
> > > struct dirent **dirent,
> > > int start,
> > > int num)
> > > @@ -733,8 +758,7 @@ static int __perf_event__synthesize_threads(struct perf_tool *tool,
> > > */
> > > __event__synthesize_thread(comm_event, mmap_event, fork_event,
> > > namespaces_event, pid, 1, process,
> > > - tool, machine, mmap_data,
> > > - proc_map_timeout);
> > > + tool, machine, mmap_data);
> > > }
> > > err = 0;
> > > @@ -754,7 +778,6 @@ struct synthesize_threads_arg {
> > > perf_event__handler_t process;
> > > struct machine *machine;
> > > bool mmap_data;
> > > - unsigned int proc_map_timeout;
> > > struct dirent **dirent;
> > > int num;
> > > int start;
> > > @@ -766,7 +789,7 @@ static void *synthesize_threads_worker(void *arg)
> > > __perf_event__synthesize_threads(args->tool, args->process,
> > > args->machine, args->mmap_data,
> > > - args->proc_map_timeout, args->dirent,
> > > + args->dirent,
> > > args->start, args->num);
> > > return NULL;
> > > }
> > > @@ -775,7 +798,6 @@ int perf_event__synthesize_threads(struct perf_tool *tool,
> > > perf_event__handler_t process,
> > > struct machine *machine,
> > > bool mmap_data,
> > > - unsigned int proc_map_timeout,
> > > unsigned int nr_threads_synthesize)
> > > {
> > > struct synthesize_threads_arg *args = NULL;
> > > @@ -805,7 +827,6 @@ int perf_event__synthesize_threads(struct perf_tool *tool,
> > > if (thread_nr <= 1) {
> > > err = __perf_event__synthesize_threads(tool, process,
> > > machine, mmap_data,
> > > - proc_map_timeout,
> > > dirent, base, n);
> > > goto free_dirent;
> > > }
> > > @@ -827,7 +848,6 @@ int perf_event__synthesize_threads(struct perf_tool *tool,
> > > args[i].process = process;
> > > args[i].machine = machine;
> > > args[i].mmap_data = mmap_data;
> > > - args[i].proc_map_timeout = proc_map_timeout;
> > > args[i].dirent = dirent;
> > > }
> > > for (i = 0; i < m; i++) {
> > > diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
> > > index bfa60bcafbde..45a3b47fc82c 100644
> > > --- a/tools/perf/util/event.h
> > > +++ b/tools/perf/util/event.h
> > > @@ -412,7 +412,6 @@ struct events_stats {
> > > u32 nr_unknown_id;
> > > u32 nr_unprocessable_samples;
> > > u32 nr_auxtrace_errors[PERF_AUXTRACE_ERROR_MAX];
> > > - u32 nr_proc_map_timeout;
> > > };
> > > enum {
> > > @@ -669,8 +668,7 @@ typedef int (*perf_event__handler_t)(struct perf_tool *tool,
> > > int perf_event__synthesize_thread_map(struct perf_tool *tool,
> > > struct thread_map *threads,
> > > perf_event__handler_t process,
> > > - struct machine *machine, bool mmap_data,
> > > - unsigned int proc_map_timeout);
> > > + struct machine *machine, bool mmap_data);
> > > int perf_event__synthesize_thread_map2(struct perf_tool *tool,
> > > struct thread_map *threads,
> > > perf_event__handler_t process,
> > > @@ -682,7 +680,6 @@ int perf_event__synthesize_cpu_map(struct perf_tool *tool,
> > > int perf_event__synthesize_threads(struct perf_tool *tool,
> > > perf_event__handler_t process,
> > > struct machine *machine, bool mmap_data,
> > > - unsigned int proc_map_timeout,
> > > unsigned int nr_threads_synthesize);
> > > int perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
> > > perf_event__handler_t process,
> > > @@ -797,8 +794,7 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool,
> > > pid_t pid, pid_t tgid,
> > > perf_event__handler_t process,
> > > struct machine *machine,
> > > - bool mmap_data,
> > > - unsigned int proc_map_timeout);
> > > + bool mmap_data);
> > > int perf_event__synthesize_extra_kmaps(struct perf_tool *tool,
> > > perf_event__handler_t process,
> > > diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
> > > index 111ae858cbcb..6427a74ebc4a 100644
> > > --- a/tools/perf/util/machine.c
> > > +++ b/tools/perf/util/machine.c
> > > @@ -2443,15 +2443,13 @@ int machines__for_each_thread(struct machines *machines,
> > > int __machine__synthesize_threads(struct machine *machine, struct perf_tool *tool,
> > > struct target *target, struct thread_map *threads,
> > > perf_event__handler_t process, bool data_mmap,
> > > - unsigned int proc_map_timeout,
> > > unsigned int nr_threads_synthesize)
> > > {
> > > if (target__has_task(target))
> > > - return perf_event__synthesize_thread_map(tool, threads, process, machine, data_mmap, proc_map_timeout);
> > > + return perf_event__synthesize_thread_map(tool, threads, process, machine, data_mmap);
> > > else if (target__has_cpu(target))
> > > return perf_event__synthesize_threads(tool, process,
> > > machine, data_mmap,
> > > - proc_map_timeout,
> > > nr_threads_synthesize);
> > > /* command specified */
> > > return 0;
> > > diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h
> > > index d856b85862e2..688d84ba823a 100644
> > > --- a/tools/perf/util/machine.h
> > > +++ b/tools/perf/util/machine.h
> > > @@ -247,17 +247,14 @@ int machines__for_each_thread(struct machines *machines,
> > > int __machine__synthesize_threads(struct machine *machine, struct perf_tool *tool,
> > > struct target *target, struct thread_map *threads,
> > > perf_event__handler_t process, bool data_mmap,
> > > - unsigned int proc_map_timeout,
> > > unsigned int nr_threads_synthesize);
> > > static inline
> > > int machine__synthesize_threads(struct machine *machine, struct target *target,
> > > struct thread_map *threads, bool data_mmap,
> > > - unsigned int proc_map_timeout,
> > > unsigned int nr_threads_synthesize)
> > > {
> > > return __machine__synthesize_threads(machine, NULL, target, threads,
> > > perf_event__process, data_mmap,
> > > - proc_map_timeout,
> > > nr_threads_synthesize);
> > > }
> > > diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
> > > index 7d2c8ce6cfad..33d2c50cdc18 100644
> > > --- a/tools/perf/util/session.c
> > > +++ b/tools/perf/util/session.c
> > > @@ -1261,8 +1261,6 @@ static int machines__deliver_event(struct machines *machines,
> > > case PERF_RECORD_MMAP:
> > > return tool->mmap(tool, event, sample, machine);
> > > case PERF_RECORD_MMAP2:
> > > - if (event->header.misc & PERF_RECORD_MISC_PROC_MAP_PARSE_TIMEOUT)
> > > - ++evlist->stats.nr_proc_map_timeout;
> > > return tool->mmap2(tool, event, sample, machine);
> > > case PERF_RECORD_COMM:
> > > return tool->comm(tool, event, sample, machine);
> > > @@ -1640,17 +1638,6 @@ static void perf_session__warn_about_errors(const struct perf_session *session)
> > > perf_session__warn_order(session);
> > > events_stats__auxtrace_error_warn(stats);
> > > -
> > > - if (stats->nr_proc_map_timeout != 0) {
> > > - ui__warning("%d map information files for pre-existing threads were\n"
> > > - "not processed, if there are samples for addresses they\n"
> > > - "will not be resolved, you may find out which are these\n"
> > > - "threads by running with -v and redirecting the output\n"
> > > - "to a file.\n"
> > > - "The time limit to process proc map is too short?\n"
> > > - "Increase it by --proc-map-timeout\n",
> > > - stats->nr_proc_map_timeout);
> > > - }
> > > }
> > > static int perf_session__flush_thread_stack(struct thread *thread,