perf top: Improve the autosizing of column lenghts

When profiling C++ workloads the symbol name length can be
really big, so cap it before it garbles the result.

This builds upon the autosizing already present where we choose
to use the short, basename of DSOs instead of its long, full
pathname.
Reported-by: NPavel Krauz <krauz@cngroup.cz>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1268676230-9261-1-git-send-email-acme@infradead.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

tools/perf/builtin-top.c

@@ -455,7 +455,7 @@ static void print_sym_table(void)
 	struct sym_entry *syme, *n;
 	struct rb_root tmp = RB_ROOT;
 	struct rb_node *nd;
-	int sym_width = 0, dso_width = 0, max_dso_width;
+	int sym_width = 0, dso_width = 0, dso_short_width;
 	const int win_width = winsize.ws_col - 1;
 
 	samples = userspace_samples = 0;
@@ -545,15 +545,20 @@ static void print_sym_table(void)
 		if (syme->map->dso->long_name_len > dso_width)
 			dso_width = syme->map->dso->long_name_len;
 
+		if (syme->map->dso->short_name_len > dso_short_width)
+			dso_short_width = syme->map->dso->short_name_len;
+
 		if (syme->name_len > sym_width)
 			sym_width = syme->name_len;
 	}
 
 	printed = 0;
 
-	max_dso_width = winsize.ws_col - sym_width - 29;
-	if (dso_width > max_dso_width)
-		dso_width = max_dso_width;
+	if (sym_width + dso_width > winsize.ws_col - 29) {
+		dso_width = dso_short_width;
+		if (sym_width + dso_width > winsize.ws_col - 29)
+			sym_width = winsize.ws_col - dso_width - 29;
+	}
 	putchar('\n');
 	if (nr_counters == 1)
 		printf("             samples  pcnt");

tools/perf/util/symbol.c

@@ -163,9 +163,17 @@ void dso__set_long_name(struct dso *self, char *name)
 	self->long_name_len = strlen(name);
 }
 
+static void dso__set_short_name(struct dso *self, const char *name)
+{
+	if (name == NULL)
+		return;
+	self->short_name = name;
+	self->short_name_len = strlen(name);
+}
+
 static void dso__set_basename(struct dso *self)
 {
-	self->short_name = basename(self->long_name);
+	dso__set_short_name(self, basename(self->long_name));
 }
 
 struct dso *dso__new(const char *name)
@@ -176,7 +184,7 @@ struct dso *dso__new(const char *name)
 		int i;
 		strcpy(self->name, name);
 		dso__set_long_name(self, self->name);
-		self->short_name = self->name;
+		dso__set_short_name(self, self->name);
 		for (i = 0; i < MAP__NR_TYPES; ++i)
 			self->symbols[i] = self->symbol_names[i] = RB_ROOT;
 		self->slen_calculated = 0;
@@ -897,7 +905,6 @@ static int dso__load_sym(struct dso *self, struct map *map, const char *name,
 	struct kmap *kmap = self->kernel ? map__kmap(map) : NULL;
 	struct map *curr_map = map;
 	struct dso *curr_dso = self;
-	size_t dso_name_len = strlen(self->short_name);
 	Elf_Data *symstrs, *secstrs;
 	uint32_t nr_syms;
 	int err = -1;
@@ -987,7 +994,8 @@ static int dso__load_sym(struct dso *self, struct map *map, const char *name,
 			char dso_name[PATH_MAX];
 
 			if (strcmp(section_name,
-				   curr_dso->short_name + dso_name_len) == 0)
+				   (curr_dso->short_name +
+				    self->short_name_len)) == 0)
 				goto new_symbol;
 
 			if (strcmp(section_name, ".text") == 0) {
@@ -1782,7 +1790,7 @@ struct dso *dso__new_kernel(const char *name)
 	struct dso *self = dso__new(name ?: "[kernel.kallsyms]");
 
 	if (self != NULL) {
-		self->short_name = "[kernel]";
+		dso__set_short_name(self, "[kernel]");
 		self->kernel	 = 1;
 	}
 

tools/perf/util/symbol.h

@@ -110,9 +110,10 @@ struct dso {
 	u8		 sorted_by_name;
 	u8		 loaded;
 	u8		 build_id[BUILD_ID_SIZE];
-	u16		 long_name_len;
 	const char	 *short_name;
 	char	 	 *long_name;
+	u16		 long_name_len;
+	u16		 short_name_len;
 	char		 name[0];
 };