Re: [PATCH RFC] perf: Go back to by-hand proc mmap parsing and kill timeout

[Arnaldo Carvalho de Melo]

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.
> 
> 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,