2 files changed, 12 insertions, 1 deletions

diff --git a/lib/libc/gmon/gmon.c b/lib/libc/gmon/gmon.c
index edf4e2f3d5eb..8f508b065a0d 100644
--- a/lib/libc/gmon/gmon.c
+++ b/lib/libc/gmon/gmon.c
@@ -157,7 +157,12 @@ _mcleanup(void)
 	}
 
 	moncontrol(0);
-	snprintf(outname, sizeof(outname), "%s.gmon", _getprogname());
+	if (getenv("PROFIL_USE_PID"))
+		snprintf(outname, sizeof(outname), "%s.%d.gmon",
+		    _getprogname(), getpid());
+	else
+		snprintf(outname, sizeof(outname), "%s.gmon", _getprogname());
+
 	fd = _open(outname, O_CREAT|O_TRUNC|O_WRONLY, 0666);
 	if (fd < 0) {
 		_warn("_mcleanup: %s", outname);
diff --git a/lib/libc/gmon/moncontrol.3 b/lib/libc/gmon/moncontrol.3
index 7979a71c9fe8..f78ceaefd22d 100644
--- a/lib/libc/gmon/moncontrol.3
+++ b/lib/libc/gmon/moncontrol.3
@@ -98,6 +98,12 @@ however, all functions in that address range will
 have their execution time measured.
 Profiling begins on return from
 .Fn monstartup .
+.Sh ENVIRONMENT
+The following environment variables affect the execution of
+.Nm :
+.Bl -tag -width ".Ev PROFIL_USE_PID"
+.It PROFIL_USE_PID
+If set, the pid of the process is inserted into the filename.
 .Sh FILES
 .Bl -tag -width progname.gmon -compact
 .It Pa progname.gmon