Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:

User visible fixes:

 - Fallback to kallsyms when using the minimal 'ELF' loader (Arnaldo Carvalho de Melo)

 - Fix annotation with kcore (Adrian Hunter)

 - Fix up srcline histogram key formatting (Arnaldo Carvalho de Melo)

 - Add missing handler for PERF_RECORD_MMAP2 events in 'perf diff' (Kan Liang)

User visible changes/new features:

 - Only print base source file for srcline histogram sort key (Andi Kleen)

 - Support source line numbers in annotate using a hotkey (Andi Kleen)

Infrastructure changes and fixes:

 - Do not poll events that use the system_wide flag (Adrian Hunter)

 - Add perf-read-vdso32 and perf-read-vdsox32 to .gitignore (Adrian Hunter)

 - Only override the default :tid comm entry (Adrian Hunter)

 - Factor out adding new call chain entries (Andi Kleen)

 - Use al.addr to set up call chain (Andi Kleen)

 - Use a common function to resolve symbol or name (Andi Kleen)

 - Fix ftrace:function event recording (Jiri Olsa)

 - Move disable_buildid_cache() to util/build-id.c (Namhyung Kim)

 - Clean up libelf feature support code (Namhyung Kim)

 - Fix typo in python 'perf test' (WANG Chao)

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

tools/perf/.gitignore

@@ -2,6 +2,8 @@ PERF-CFLAGS
 PERF-GUI-VARS
 PERF-VERSION-FILE
 perf
+perf-read-vdso32
+perf-read-vdsox32
 perf-help
 perf-record
 perf-report

tools/perf/Makefile.perf

@@ -497,8 +497,6 @@ ifneq ($(OUTPUT),)
 endif
 
 ifdef NO_LIBELF
-EXTLIBS := $(filter-out -lelf,$(EXTLIBS))
-
 # Remove ELF/DWARF dependent codes
 LIB_OBJS := $(filter-out $(OUTPUT)util/symbol-elf.o,$(LIB_OBJS))
 LIB_OBJS := $(filter-out $(OUTPUT)util/dwarf-aux.o,$(LIB_OBJS))

tools/perf/builtin-diff.c

@@ -357,6 +357,7 @@ static int diff__process_sample_event(struct perf_tool *tool __maybe_unused,
 static struct perf_tool tool = {
 	.sample	= diff__process_sample_event,
 	.mmap	= perf_event__process_mmap,
+	.mmap2	= perf_event__process_mmap2,
 	.comm	= perf_event__process_comm,
 	.exit	= perf_event__process_exit,
 	.fork	= perf_event__process_fork,

tools/perf/config/Makefile

@@ -150,7 +150,7 @@ CFLAGS += -std=gnu99
 # adding assembler files missing the .GNU-stack linker note.
 LDFLAGS += -Wl,-z,noexecstack
 
-EXTLIBS = -lelf -lpthread -lrt -lm -ldl
+EXTLIBS = -lpthread -lrt -lm -ldl
 
 ifneq ($(OUTPUT),)
   OUTPUT_FEATURES = $(OUTPUT)config/feature-checks/
@@ -354,6 +354,7 @@ endif # NO_LIBELF
 
 ifndef NO_LIBELF
   CFLAGS += -DHAVE_LIBELF_SUPPORT
+  EXTLIBS += -lelf
 
   ifeq ($(feature-libelf-mmap), 1)
     CFLAGS += -DHAVE_LIBELF_MMAP_SUPPORT
@@ -373,7 +374,7 @@ ifndef NO_LIBELF
     else
       CFLAGS += -DHAVE_DWARF_SUPPORT $(LIBDW_CFLAGS)
       LDFLAGS += $(LIBDW_LDFLAGS)
-      EXTLIBS += -lelf -ldw
+      EXTLIBS += -ldw
     endif # PERF_HAVE_DWARF_REGS
   endif # NO_DWARF
 endif # NO_LIBELF

tools/perf/tests/builtin-test.c

@@ -85,7 +85,7 @@ static struct test {
 		.func = test__hists_link,
 	},
 	{
-		.desc = "Try 'use perf' in python, checking link problems",
+		.desc = "Try 'import perf' in python, checking link problems",
 		.func = test__python_use,
 	},
 	{

tools/perf/ui/browsers/annotate.c

@@ -27,6 +27,7 @@ static struct annotate_browser_opt {
 	bool hide_src_code,
 	     use_offset,
 	     jump_arrows,
+	     show_linenr,
 	     show_nr_jumps;
 } annotate_browser__opts = {
 	.use_offset	= true,
@@ -128,7 +129,11 @@ static void annotate_browser__write(struct ui_browser *browser, void *entry, int
 	if (!*dl->line)
 		slsmg_write_nstring(" ", width - pcnt_width);
 	else if (dl->offset == -1) {
-		printed = scnprintf(bf, sizeof(bf), "%*s  ",
+		if (dl->line_nr && annotate_browser__opts.show_linenr)
+			printed = scnprintf(bf, sizeof(bf), "%-*d ",
+					ab->addr_width + 1, dl->line_nr);
+		else
+			printed = scnprintf(bf, sizeof(bf), "%*s  ",
 				    ab->addr_width, " ");
 		slsmg_write_nstring(bf, printed);
 		slsmg_write_nstring(dl->line, width - printed - pcnt_width + 1);
@@ -733,6 +738,7 @@ static int annotate_browser__run(struct annotate_browser *browser,
 		"o             Toggle disassembler output/simplified view\n"
 		"s             Toggle source code view\n"
 		"/             Search string\n"
+		"k             Toggle line numbers\n"
 		"r             Run available scripts\n"
 		"?             Search string backwards\n");
 			continue;
@@ -741,6 +747,10 @@ static int annotate_browser__run(struct annotate_browser *browser,
 				script_browse(NULL);
 				continue;
 			}
+		case 'k':
+			annotate_browser__opts.show_linenr =
+				!annotate_browser__opts.show_linenr;
+			break;
 		case 'H':
 			nd = browser->curr_hot;
 			break;
@@ -984,6 +994,7 @@ static struct annotate_config {
 } annotate__configs[] = {
 	ANNOTATE_CFG(hide_src_code),
 	ANNOTATE_CFG(jump_arrows),
+	ANNOTATE_CFG(show_linenr),
 	ANNOTATE_CFG(show_nr_jumps),
 	ANNOTATE_CFG(use_offset),
 };

tools/perf/ui/browsers/hists.c

@@ -463,23 +463,6 @@ out:
 	return key;
 }
 
-static char *callchain_list__sym_name(struct callchain_list *cl,
-				      char *bf, size_t bfsize, bool show_dso)
-{
-	int printed;
-
-	if (cl->ms.sym)
-		printed = scnprintf(bf, bfsize, "%s", cl->ms.sym->name);
-	else
-		printed = scnprintf(bf, bfsize, "%#" PRIx64, cl->ip);
-
-	if (show_dso)
-		scnprintf(bf + printed, bfsize - printed, " %s",
-			  cl->ms.map ? cl->ms.map->dso->short_name : "unknown");
-
-	return bf;
-}
-
 struct callchain_print_arg {
 	/* for hists browser */
 	off_t	row_offset;

tools/perf/ui/gtk/hists.c

@@ -89,15 +89,6 @@ void perf_gtk__init_hpp(void)
 				perf_gtk__hpp_color_overhead_acc;
 }
 
-static void callchain_list__sym_name(struct callchain_list *cl,
-				     char *bf, size_t bfsize)
-{
-	if (cl->ms.sym)
-		scnprintf(bf, bfsize, "%s", cl->ms.sym->name);
-	else
-		scnprintf(bf, bfsize, "%#" PRIx64, cl->ip);
-}
-
 static void perf_gtk__add_callchain(struct rb_root *root, GtkTreeStore *store,
 				    GtkTreeIter *parent, int col, u64 total)
 {
@@ -128,7 +119,7 @@ static void perf_gtk__add_callchain(struct rb_root *root, GtkTreeStore *store,
 			scnprintf(buf, sizeof(buf), "%5.2f%%", percent);
 			gtk_tree_store_set(store, &iter, 0, buf, -1);
 
-			callchain_list__sym_name(chain, buf, sizeof(buf));
+			callchain_list__sym_name(chain, buf, sizeof(buf), false);
 			gtk_tree_store_set(store, &iter, col, buf, -1);
 
 			if (need_new_parent) {

tools/perf/ui/stdio/hist.c

@@ -41,6 +41,7 @@ static size_t ipchain__fprintf_graph(FILE *fp, struct callchain_list *chain,
 {
 	int i;
 	size_t ret = 0;
+	char bf[1024];
 
 	ret += callchain__fprintf_left_margin(fp, left_margin);
 	for (i = 0; i < depth; i++) {
@@ -56,11 +57,8 @@ static size_t ipchain__fprintf_graph(FILE *fp, struct callchain_list *chain,
 		} else
 			ret += fprintf(fp, "%s", "          ");
 	}
-	if (chain->ms.sym)
-		ret += fprintf(fp, "%s\n", chain->ms.sym->name);
-	else
-		ret += fprintf(fp, "0x%0" PRIx64 "\n", chain->ip);
-
+	fputs(callchain_list__sym_name(chain, bf, sizeof(bf), false), fp);
+	fputc('\n', fp);
 	return ret;
 }
 
@@ -168,6 +166,7 @@ static size_t callchain__fprintf_graph(FILE *fp, struct rb_root *root,
 	struct rb_node *node;
 	int i = 0;
 	int ret = 0;
+	char bf[1024];
 
 	/*
 	 * If have one single callchain root, don't bother printing
@@ -196,10 +195,8 @@ static size_t callchain__fprintf_graph(FILE *fp, struct rb_root *root,
 			} else
 				ret += callchain__fprintf_left_margin(fp, left_margin);
 
-			if (chain->ms.sym)
-				ret += fprintf(fp, " %s\n", chain->ms.sym->name);
-			else
-				ret += fprintf(fp, " %p\n", (void *)(long)chain->ip);
+			ret += fprintf(fp, "%s\n", callchain_list__sym_name(chain, bf, sizeof(bf),
+							false));
 
 			if (++entries_printed == callchain_param.print_limit)
 				break;
@@ -219,6 +216,7 @@ static size_t __callchain__fprintf_flat(FILE *fp, struct callchain_node *node,
 {
 	struct callchain_list *chain;
 	size_t ret = 0;
+	char bf[1024];
 
 	if (!node)
 		return 0;
@@ -229,11 +227,8 @@ static size_t __callchain__fprintf_flat(FILE *fp, struct callchain_node *node,
 	list_for_each_entry(chain, &node->val, list) {
 		if (chain->ip >= PERF_CONTEXT_MAX)
 			continue;
-		if (chain->ms.sym)
-			ret += fprintf(fp, "                %s\n", chain->ms.sym->name);
-		else
-			ret += fprintf(fp, "                %p\n",
-					(void *)(long)chain->ip);
+		ret += fprintf(fp, "                %s\n", callchain_list__sym_name(chain,
+					bf, sizeof(bf), false));
 	}
 
 	return ret;

tools/perf/util/annotate.c

@@ -17,11 +17,13 @@
 #include "debug.h"
 #include "annotate.h"
 #include "evsel.h"
+#include <regex.h>
 #include <pthread.h>
 #include <linux/bitops.h>
 
 const char 	*disassembler_style;
 const char	*objdump_path;
+static regex_t	 file_lineno;
 
 static struct ins *ins__find(const char *name);
 static int disasm_line__parse(char *line, char **namep, char **rawp);
@@ -570,13 +572,15 @@ out_free_name:
 	return -1;
 }
 
-static struct disasm_line *disasm_line__new(s64 offset, char *line, size_t privsize)
+static struct disasm_line *disasm_line__new(s64 offset, char *line,
+					size_t privsize, int line_nr)
 {
 	struct disasm_line *dl = zalloc(sizeof(*dl) + privsize);
 
 	if (dl != NULL) {
 		dl->offset = offset;
 		dl->line = strdup(line);
+		dl->line_nr = line_nr;
 		if (dl->line == NULL)
 			goto out_delete;
 
@@ -788,13 +792,15 @@ static int disasm_line__print(struct disasm_line *dl, struct symbol *sym, u64 st
  * The ops.raw part will be parsed further according to type of the instruction.
  */
 static int symbol__parse_objdump_line(struct symbol *sym, struct map *map,
-				      FILE *file, size_t privsize)
+				      FILE *file, size_t privsize,
+				      int *line_nr)
 {
 	struct annotation *notes = symbol__annotation(sym);
 	struct disasm_line *dl;
 	char *line = NULL, *parsed_line, *tmp, *tmp2, *c;
 	size_t line_len;
 	s64 line_ip, offset = -1;
+	regmatch_t match[2];
 
 	if (getline(&line, &line_len, file) < 0)
 		return -1;
@@ -812,6 +818,12 @@ static int symbol__parse_objdump_line(struct symbol *sym, struct map *map,
 	line_ip = -1;
 	parsed_line = line;
 
+	/* /filename:linenr ? Save line number and ignore. */
+	if (regexec(&file_lineno, line, 2, match, 0) == 0) {
+		*line_nr = atoi(line + match[1].rm_so);
+		return 0;
+	}
+
 	/*
 	 * Strip leading spaces:
 	 */
@@ -842,8 +854,9 @@ static int symbol__parse_objdump_line(struct symbol *sym, struct map *map,
 			parsed_line = tmp2 + 1;
 	}
 
-	dl = disasm_line__new(offset, parsed_line, privsize);
+	dl = disasm_line__new(offset, parsed_line, privsize, *line_nr);
 	free(line);
+	(*line_nr)++;
 
 	if (dl == NULL)
 		return -1;
@@ -869,6 +882,11 @@ static int symbol__parse_objdump_line(struct symbol *sym, struct map *map,
 	return 0;
 }
 
+static __attribute__((constructor)) void symbol__init_regexpr(void)
+{
+	regcomp(&file_lineno, "^/[^:]+:([0-9]+)", REG_EXTENDED);
+}
+
 static void delete_last_nop(struct symbol *sym)
 {
 	struct annotation *notes = symbol__annotation(sym);
@@ -904,6 +922,7 @@ int symbol__annotate(struct symbol *sym, struct map *map, size_t privsize)
 	char symfs_filename[PATH_MAX];
 	struct kcore_extract kce;
 	bool delete_extract = false;
+	int lineno = 0;
 
 	if (filename)
 		symbol__join_symfs(symfs_filename, filename);
@@ -915,6 +934,8 @@ int symbol__annotate(struct symbol *sym, struct map *map, size_t privsize)
 			return -ENOMEM;
 		}
 		goto fallback;
+	} else if (dso__is_kcore(dso)) {
+		goto fallback;
 	} else if (readlink(symfs_filename, command, sizeof(command)) < 0 ||
 		   strstr(command, "[kernel.kallsyms]") ||
 		   access(symfs_filename, R_OK)) {
@@ -982,7 +1003,7 @@ fallback:
 	snprintf(command, sizeof(command),
 		 "%s %s%s --start-address=0x%016" PRIx64
 		 " --stop-address=0x%016" PRIx64
-		 " -d %s %s -C %s 2>/dev/null|grep -v %s|expand",
+		 " -l -d %s %s -C %s 2>/dev/null|grep -v %s|expand",
 		 objdump_path ? objdump_path : "objdump",
 		 disassembler_style ? "-M " : "",
 		 disassembler_style ? disassembler_style : "",
@@ -999,7 +1020,8 @@ fallback:
 		goto out_free_filename;
 
 	while (!feof(file))
-		if (symbol__parse_objdump_line(sym, map, file, privsize) < 0)
+		if (symbol__parse_objdump_line(sym, map, file, privsize,
+			    &lineno) < 0)
 			break;
 
 	/*

tools/perf/util/annotate.h

@@ -58,6 +58,7 @@ struct disasm_line {
 	char		    *line;
 	char		    *name;
 	struct ins	    *ins;
+	int		    line_nr;
 	struct ins_operands ops;
 };
 

tools/perf/util/build-id.c

@@ -18,6 +18,9 @@
 #include "header.h"
 #include "vdso.h"
 
+
+static bool no_buildid_cache;
+
 int build_id__mark_dso_hit(struct perf_tool *tool __maybe_unused,
 			   union perf_event *event,
 			   struct perf_sample *sample,
@@ -251,6 +254,11 @@ int dsos__hit_all(struct perf_session *session)
 	return 0;
 }
 
+void disable_buildid_cache(void)
+{
+	no_buildid_cache = true;
+}
+
 int build_id_cache__add_s(const char *sbuild_id, const char *debugdir,
 			  const char *name, bool is_kallsyms, bool is_vdso)
 {
@@ -404,6 +412,9 @@ int perf_session__cache_build_ids(struct perf_session *session)
 	int ret;
 	char debugdir[PATH_MAX];
 
+	if (no_buildid_cache)
+		return 0;
+
 	snprintf(debugdir, sizeof(debugdir), "%s", buildid_dir);
 
 	if (mkdir(debugdir, 0755) != 0 && errno != EEXIST)

tools/perf/util/build-id.h

@@ -25,5 +25,6 @@ int perf_session__cache_build_ids(struct perf_session *session);
 int build_id_cache__add_s(const char *sbuild_id, const char *debugdir,
 			  const char *name, bool is_kallsyms, bool is_vdso);
 int build_id_cache__remove_s(const char *sbuild_id, const char *debugdir);
+void disable_buildid_cache(void);
 
 #endif

tools/perf/util/callchain.c

@@ -808,3 +808,22 @@ int fill_callchain_info(struct addr_location *al, struct callchain_cursor_node *
 out:
 	return 1;
 }
+
+char *callchain_list__sym_name(struct callchain_list *cl,
+			       char *bf, size_t bfsize, bool show_dso)
+{
+	int printed;
+
+	if (cl->ms.sym) {
+		printed = scnprintf(bf, bfsize, "%s", cl->ms.sym->name);
+	} else
+		printed = scnprintf(bf, bfsize, "%#" PRIx64, cl->ip);
+
+	if (show_dso)
+		scnprintf(bf + printed, bfsize - printed, " %s",
+			  cl->ms.map ?
+			  cl->ms.map->dso->short_name :
+			  "unknown");
+
+	return bf;
+}

tools/perf/util/callchain.h

@@ -193,4 +193,7 @@ static inline int arch_skip_callchain_idx(struct thread *thread __maybe_unused,
 }
 #endif
 
+char *callchain_list__sym_name(struct callchain_list *cl,
+			       char *bf, size_t bfsize, bool show_dso);
+
 #endif	/* __PERF_CALLCHAIN_H */

tools/perf/util/evlist.c

@@ -816,7 +816,15 @@ static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx,
 			perf_evlist__mmap_get(evlist, idx);
 		}
 
-		if (__perf_evlist__add_pollfd(evlist, fd, idx) < 0) {
+		/*
+		 * The system_wide flag causes a selected event to be opened
+		 * always without a pid.  Consequently it will never get a
+		 * POLLHUP, but it is used for tracking in combination with
+		 * other events, so it should not need to be polled anyway.
+		 * Therefore don't add it for polling.
+		 */
+		if (!evsel->system_wide &&
+		    __perf_evlist__add_pollfd(evlist, fd, idx) < 0) {
 			perf_evlist__mmap_put(evlist, idx);
 			return -1;
 		}

tools/perf/util/evsel.c

@@ -658,6 +658,14 @@ void perf_evsel__config(struct perf_evsel *evsel, struct record_opts *opts)
 		attr->mmap_data = track;
 	}
 
+	/*
+	 * We don't allow user space callchains for  function trace
+	 * event, due to issues with page faults while tracing page
+	 * fault handler and its overall trickiness nature.
+	 */
+	if (perf_evsel__is_function_event(evsel))
+		evsel->attr.exclude_callchain_user = 1;
+
 	if (callchain_param.enabled && !evsel->no_aux_samples)
 		perf_evsel__config_callgraph(evsel);
 

tools/perf/util/header.c

@@ -24,8 +24,6 @@
 #include "build-id.h"
 #include "data.h"
 
-static bool no_buildid_cache = false;
-
 static u32 header_argc;
 static const char **header_argv;
 
@@ -191,8 +189,7 @@ static int write_build_id(int fd, struct perf_header *h,
 		pr_debug("failed to write buildid table\n");
 		return err;
 	}
-	if (!no_buildid_cache)
-		perf_session__cache_build_ids(session);
+	perf_session__cache_build_ids(session);
 
 	return 0;
 }
@@ -2791,8 +2788,3 @@ int perf_event__process_build_id(struct perf_tool *tool __maybe_unused,
 				 session);
 	return 0;
 }
-
-void disable_buildid_cache(void)
-{
-	no_buildid_cache = true;
-}

tools/perf/util/machine.c

@@ -1381,6 +1381,34 @@ struct mem_info *sample__resolve_mem(struct perf_sample *sample,
 	return mi;
 }
 
+static int add_callchain_ip(struct thread *thread,
+			    struct symbol **parent,
+			    struct addr_location *root_al,
+			    int cpumode,
+			    u64 ip)
+{
+	struct addr_location al;
+
+	al.filtered = 0;
+	al.sym = NULL;
+	thread__find_addr_location(thread, cpumode, MAP__FUNCTION,
+				   ip, &al);
+	if (al.sym != NULL) {
+		if (sort__has_parent && !*parent &&
+		    symbol__match_regex(al.sym, &parent_regex))
+			*parent = al.sym;
+		else if (have_ignore_callees && root_al &&
+		  symbol__match_regex(al.sym, &ignore_callees_regex)) {
+			/* Treat this symbol as the root,
+			   forgetting its callees. */
+			*root_al = al;
+			callchain_cursor_reset(&callchain_cursor);
+		}
+	}
+
+	return callchain_cursor_append(&callchain_cursor, al.addr, al.map, al.sym);
+}
+
 struct branch_info *sample__resolve_bstack(struct perf_sample *sample,
 					   struct addr_location *al)
 {
@@ -1427,7 +1455,6 @@ static int thread__resolve_callchain_sample(struct thread *thread,
 
 	for (i = 0; i < chain_nr; i++) {
 		u64 ip;
-		struct addr_location al;
 
 		if (callchain_param.order == ORDER_CALLEE)
 			j = i;
@@ -1464,24 +1491,10 @@ static int thread__resolve_callchain_sample(struct thread *thread,
 			continue;
 		}
 
-		al.filtered = 0;
-		thread__find_addr_location(thread, cpumode,
-					   MAP__FUNCTION, ip, &al);
-		if (al.sym != NULL) {
-			if (sort__has_parent && !*parent &&
-			    symbol__match_regex(al.sym, &parent_regex))
-				*parent = al.sym;
-			else if (have_ignore_callees && root_al &&
-			  symbol__match_regex(al.sym, &ignore_callees_regex)) {
-				/* Treat this symbol as the root,
-				   forgetting its callees. */
-				*root_al = al;
-				callchain_cursor_reset(&callchain_cursor);
-			}
-		}
-
-		err = callchain_cursor_append(&callchain_cursor,
-					      ip, al.map, al.sym);
+		err = add_callchain_ip(thread, parent, root_al,
+				       cpumode, ip);
+		if (err == -EINVAL)
+			break;
 		if (err)
 			return err;
 	}

tools/perf/util/sort.c

@@ -309,7 +309,7 @@ sort__srcline_cmp(struct hist_entry *left, struct hist_entry *right)
 static int hist_entry__srcline_snprintf(struct hist_entry *he, char *bf,
 					size_t size, unsigned int width)
 {
-	return repsep_snprintf(bf, size, "%*.*-s", width, width, he->srcline);
+	return repsep_snprintf(bf, size, "%-*.*s", width, width, he->srcline);
 }
 
 struct sort_entry sort_srcline = {

tools/perf/util/srcline.c

@@ -274,7 +274,7 @@ char *get_srcline(struct dso *dso, unsigned long addr)
 	if (!addr2line(dso_name, addr, &file, &line, dso))
 		goto out;
 
-	if (asprintf(&srcline, "%s:%u", file, line) < 0) {
+	if (asprintf(&srcline, "%s:%u", basename(file), line) < 0) {
 		free(file);
 		goto out;
 	}

tools/perf/util/symbol-minimal.c

@@ -341,7 +341,6 @@ int dso__load_sym(struct dso *dso, struct map *map __maybe_unused,
 
 	if (filename__read_build_id(ss->name, build_id, BUILD_ID_SIZE) > 0) {
 		dso__set_build_id(dso, build_id);
-		return 1;
 	}
 	return 0;
 }

tools/perf/util/thread.c

@@ -103,15 +103,14 @@ struct comm *thread__exec_comm(const struct thread *thread)
 	return last;
 }
 
-/* CHECKME: time should always be 0 if event aren't ordered */
 int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp,
 		       bool exec)
 {
 	struct comm *new, *curr = thread__comm(thread);
 	int err;
 
-	/* Override latest entry if it had no specific time coverage */
-	if (!curr->start && !curr->exec) {
+	/* Override the default :tid entry */
+	if (!thread->comm_set) {
 		err = comm__override(curr, str, timestamp, exec);
 		if (err)
 			return err;

tools/perf/util/util.h

@@ -154,7 +154,6 @@ extern void set_die_routine(void (*routine)(const char *err, va_list params) NOR
 
 extern int prefixcmp(const char *str, const char *prefix);
 extern void set_buildid_dir(void);
-extern void disable_buildid_cache(void);
 
 static inline const char *skip_prefix(const char *str, const char *prefix)
 {