[PATCH] perf tools: improve robutness of topology parsing code

[Stephane Eranian <eranian@google.com>]

This patch improves the robutness of the build_cpu_topo()
routine by allowing either the CPU parsing or the thread
parsing to fail and yet get perf to produce some topology
data which could be useful for the analysis. Without this
patch, if the cpu parsing fails, the thread parsing is not
attempted vice-versa.

Signed-off-by: Stephane Eranian <eranian@google.com>
---

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index f558f83..c993204 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -716,18 +716,19 @@ static int build_cpu_topo(struct cpu_topo *tp, int cpu)
 	char filename[MAXPATHLEN];
 	char *buf = NULL, *p;
 	size_t len = 0;
+	ssize_t sret;
 	u32 i = 0;
 	int ret = -1;
 
 	sprintf(filename, CORE_SIB_FMT, cpu);
 	fp = fopen(filename, "r");
 	if (!fp)
-		return -1;
-
-	if (getline(&buf, &len, fp) <= 0)
-		goto done;
-
+		goto try_threads;
+		
+	sret = getline(&buf, &len, fp);
 	fclose(fp);
+	if (sret <= 0)
+		goto try_threads;
 
 	p = strchr(buf, '\n');
 	if (p)
@@ -743,7 +744,9 @@ static int build_cpu_topo(struct cpu_topo *tp, int cpu)
 		buf = NULL;
 		len = 0;
 	}
+	ret = 0;
 
+try_threads:
 	sprintf(filename, THRD_SIB_FMT, cpu);
 	fp = fopen(filename, "r");
 	if (!fp)