8031126: java/lang/management/ThreadMXBean/ThreadUserTime.java fails intermittently
Reviewed-by: coleenp, simonis, goetz, gthornbr
--- a/hotspot/src/os/linux/vm/os_linux.cpp Fri May 02 11:06:26 2014 -0700
+++ b/hotspot/src/os/linux/vm/os_linux.cpp Mon May 05 20:17:19 2014 +0200
@@ -5271,7 +5271,6 @@
//
static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
- static bool proc_task_unchecked = true;
pid_t tid = thread->osthread()->thread_id();
char *s;
char stat[2048];
@@ -5284,24 +5283,7 @@
long ldummy;
FILE *fp;
- snprintf(proc_name, 64, "/proc/%d/stat", tid);
-
- // The /proc/<tid>/stat aggregates per-process usage on
- // new Linux kernels 2.6+ where NPTL is supported.
- // The /proc/self/task/<tid>/stat still has the per-thread usage.
- // See bug 6328462.
- // There possibly can be cases where there is no directory
- // /proc/self/task, so we check its availability.
- if (proc_task_unchecked && os::Linux::is_NPTL()) {
- // This is executed only once
- proc_task_unchecked = false;
- fp = fopen("/proc/self/task", "r");
- if (fp != NULL) {
- snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid);
- fclose(fp);
- }
- }
-
+ snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid);
fp = fopen(proc_name, "r");
if ( fp == NULL ) return -1;
statlen = fread(stat, 1, 2047, fp);