perf_counter tools: Print out symbol parsing errors only if --verbose

Also, add a suggestion to 'perf report', if the default sort order is
used.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/Documentation/perf_counter/builtin-report.c b/Documentation/perf_counter/builtin-report.c
index 56c664d..15fe9da 100644
--- a/Documentation/perf_counter/builtin-report.c
+++ b/Documentation/perf_counter/builtin-report.c
@@ -26,7 +26,10 @@
 
 static char		const *input_name = "perf.data";
 static char		*vmlinux = NULL;
-static char		*sort_order = "comm,dso";
+
+static char		default_sort_order[] = "comm,dso";
+static char		*sort_order = default_sort_order;
+
 static int		input;
 static int		show_mask = SHOW_KERNEL | SHOW_USER | SHOW_HV;
 
@@ -103,9 +106,10 @@
 	if (!dso)
 		goto out_delete_dso;
 
-	nr = dso__load(dso, NULL);
+	nr = dso__load(dso, NULL, verbose);
 	if (nr < 0) {
-		fprintf(stderr, "Failed to open: %s\n", name);
+		if (verbose)
+			fprintf(stderr, "Failed to open: %s\n", name);
 		goto out_delete_dso;
 	}
 	if (!nr && verbose) {
@@ -139,7 +143,7 @@
 	if (!kernel_dso)
 		return -1;
 
-	err = dso__load_kernel(kernel_dso, vmlinux, NULL);
+	err = dso__load_kernel(kernel_dso, vmlinux, NULL, verbose);
 	if (err) {
 		dso__delete(kernel_dso);
 		kernel_dso = NULL;
@@ -741,6 +745,12 @@
 		ret += hist_entry__fprintf(fp, pos, total_samples);
 	}
 
+	if (!strcmp(sort_order, default_sort_order)) {
+		fprintf(fp, "#\n");
+		fprintf(fp, "# ( For more details, try: perf report --sort comm,dso,symbol )\n");
+		fprintf(fp, "#\n");
+	}
+
 	return ret;
 }
 
diff --git a/Documentation/perf_counter/builtin-top.c b/Documentation/perf_counter/builtin-top.c
index 3f7778b..548a8da 100644
--- a/Documentation/perf_counter/builtin-top.c
+++ b/Documentation/perf_counter/builtin-top.c
@@ -349,7 +349,7 @@
 	if (kernel_dso == NULL)
 		return -1;
 
-	if (dso__load_kernel(kernel_dso, NULL, symbol_filter) != 0)
+	if (dso__load_kernel(kernel_dso, NULL, symbol_filter, 1) != 0)
 		goto out_delete_dso;
 
 	node = rb_first(&kernel_dso->syms);
diff --git a/Documentation/perf_counter/util/symbol.c b/Documentation/perf_counter/util/symbol.c
index 35ee6de..15d5cf9 100644
--- a/Documentation/perf_counter/util/symbol.c
+++ b/Documentation/perf_counter/util/symbol.c
@@ -124,7 +124,7 @@
 	return ret;
 }
 
-static int dso__load_kallsyms(struct dso *self, symbol_filter_t filter)
+static int dso__load_kallsyms(struct dso *self, symbol_filter_t filter, int verbose)
 {
 	struct rb_node *nd, *prevnd;
 	char *line = NULL;
@@ -370,7 +370,7 @@
 }
 
 static int dso__load_sym(struct dso *self, int fd, const char *name,
-			 symbol_filter_t filter)
+			 symbol_filter_t filter, int verbose)
 {
 	Elf_Data *symstrs;
 	uint32_t nr_syms;
@@ -387,13 +387,15 @@
 
 	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
 	if (elf == NULL) {
-		fprintf(stderr, "%s: cannot read %s ELF file.\n",
-			__func__, name);
+		if (verbose)
+			fprintf(stderr, "%s: cannot read %s ELF file.\n",
+				__func__, name);
 		goto out_close;
 	}
 
 	if (gelf_getehdr(elf, &ehdr) == NULL) {
-		fprintf(stderr, "%s: cannot get elf header.\n", __func__);
+		if (verbose)
+			fprintf(stderr, "%s: cannot get elf header.\n", __func__);
 		goto out_elf_end;
 	}
 
@@ -473,7 +475,7 @@
 	return err;
 }
 
-int dso__load(struct dso *self, symbol_filter_t filter)
+int dso__load(struct dso *self, symbol_filter_t filter, int verbose)
 {
 	int size = strlen(self->name) + sizeof("/usr/lib/debug%s.debug");
 	char *name = malloc(size);
@@ -505,7 +507,7 @@
 		fd = open(name, O_RDONLY);
 	} while (fd < 0);
 
-	ret = dso__load_sym(self, fd, name, filter);
+	ret = dso__load_sym(self, fd, name, filter, verbose);
 	close(fd);
 
 	/*
@@ -520,28 +522,29 @@
 }
 
 static int dso__load_vmlinux(struct dso *self, const char *vmlinux,
-			     symbol_filter_t filter)
+			     symbol_filter_t filter, int verbose)
 {
 	int err, fd = open(vmlinux, O_RDONLY);
 
 	if (fd < 0)
 		return -1;
 
-	err = dso__load_sym(self, fd, vmlinux, filter);
+	err = dso__load_sym(self, fd, vmlinux, filter, verbose);
 	close(fd);
 
 	return err;
 }
 
-int dso__load_kernel(struct dso *self, const char *vmlinux, symbol_filter_t filter)
+int dso__load_kernel(struct dso *self, const char *vmlinux,
+		     symbol_filter_t filter, int verbose)
 {
 	int err = -1;
 
 	if (vmlinux)
-		err = dso__load_vmlinux(self, vmlinux, filter);
+		err = dso__load_vmlinux(self, vmlinux, filter, verbose);
 
 	if (err)
-		err = dso__load_kallsyms(self, filter);
+		err = dso__load_kallsyms(self, filter, verbose);
 
 	return err;
 }
diff --git a/Documentation/perf_counter/util/symbol.h b/Documentation/perf_counter/util/symbol.h
index b0299bc..8dd8522 100644
--- a/Documentation/perf_counter/util/symbol.h
+++ b/Documentation/perf_counter/util/symbol.h
@@ -32,8 +32,8 @@
 struct symbol *dso__find_symbol(struct dso *self, uint64_t ip);
 
 int dso__load_kernel(struct dso *self, const char *vmlinux,
-		     symbol_filter_t filter);
-int dso__load(struct dso *self, symbol_filter_t filter);
+		     symbol_filter_t filter, int verbose);
+int dso__load(struct dso *self, symbol_filter_t filter, int verbose);
 
 size_t dso__fprintf(struct dso *self, FILE *fp);