diff --git a/jemalloc/configure.ac b/jemalloc/configure.ac
index 17c7aa64..b6ded7bc 100644
--- a/jemalloc/configure.ac
+++ b/jemalloc/configure.ac
@@ -688,10 +688,13 @@ fi
 AC_SUBST([enable_prof])
 if test "x$enable_prof" = "x0" ; then
   roff_prof=".\\\" "
+  roff_no_prof=""
 else
   roff_prof=""
+  roff_no_prof=".\\\" "
 fi
 AC_SUBST([roff_prof])
+AC_SUBST([roff_no_prof])
 
 dnl If libunwind isn't enabled, try to use libgcc rather than gcc intrinsics
 dnl for backtracing.
diff --git a/jemalloc/doc/jemalloc.3.in b/jemalloc/doc/jemalloc.3.in
index e6611777..3865ac9b 100644
--- a/jemalloc/doc/jemalloc.3.in
+++ b/jemalloc/doc/jemalloc.3.in
@@ -38,7 +38,7 @@
 .\"     @(#)malloc.3	8.1 (Berkeley) 6/4/93
 .\" $FreeBSD: head/lib/libc/stdlib/malloc.3 182225 2008-08-27 02:00:53Z jasone $
 .\"
-.Dd January 27, 2010
+.Dd February 11, 2010
 .Dt JEMALLOC 3
 .Os
 .Sh NAME
@@ -345,7 +345,12 @@ will disable dirty page purging.
 @roff_prof@.Xr atexit 3
 @roff_prof@function to dump final memory usage to a file named according to
 @roff_prof@the pattern
-@roff_prof@.Pa jeprof.<pid>.<seq>.f.heap .
+@roff_prof@.Pa <prefix>.<pid>.<seq>.f.heap ,
+@roff_prof@where
+@roff_prof@.Pa <prefix>
+@roff_prof@is controlled by the
+@roff_prof@JEMALLOC_PROF_PREFIX
+@roff_prof@environment variable.
 @roff_prof@See the
 @roff_prof@.Dq B
 @roff_prof@option for backtrace depth control.
@@ -390,7 +395,12 @@ will disable dirty page purging.
 @roff_prof@This is an artifact of the concurrent algorithm that is used to
 @roff_prof@track allocation activity.
 @roff_prof@Profiles are dumped to files named according to the pattern
-@roff_prof@.Pa jeprof.<pid>.<seq>.i<iseq>.heap .
+@roff_prof@.Pa <prefix>.<pid>.<seq>.i<iseq>.heap ,
+@roff_prof@where
+@roff_prof@.Pa <prefix>
+@roff_prof@is controlled by the
+@roff_prof@JEMALLOC_PROF_PREFIX
+@roff_prof@environment variable.
 @roff_prof@The default maximum interval is 4 GiB.
 @roff_fill@.It J
 @roff_fill@Each byte of new memory allocated by
@@ -474,7 +484,12 @@ The default value is 128 bytes.
 @roff_prof@Trigger a memory profile dump every time the total virtual memory
 @roff_prof@exceeds the previous maximum.
 @roff_prof@Profiles are dumped to files named according to the pattern
-@roff_prof@.Pa jeprof.<pid>.<seq>.u<useq>.heap .
+@roff_prof@.Pa <prefix>.<pid>.<seq>.u<useq>.heap ,
+@roff_prof@where
+@roff_prof@.Pa <prefix>
+@roff_prof@is controlled by the
+@roff_prof@JEMALLOC_PROF_PREFIX
+@roff_prof@environment variable.
 @roff_prof@This option is disabled by default.
 @roff_sysv@.It V
 @roff_sysv@Attempting to allocate zero bytes will return a
@@ -970,7 +985,12 @@ Maximum size supported by this large size class.
 @roff_prof@.It Sy "prof.dump (void) --"
 @roff_prof@.Bd -ragged -offset indent -compact
 @roff_prof@Dump a memory profile to a file according to the pattern
-@roff_prof@.Pa jeprof.<pid>.<seq>.m<mseq>.heap .
+@roff_prof@.Pa <prefix>.<pid>.<seq>.m<mseq>.heap ,
+@roff_prof@where
+@roff_prof@.Pa <prefix>
+@roff_prof@is controlled by the
+@roff_prof@JEMALLOC_PROF_PREFIX
+@roff_prof@environment variable.
 @roff_prof@.Ed
 .\"-----------------------------------------------------------------------------
 @roff_stats@.It Sy "stats.allocated (size_t) r-"
@@ -1356,12 +1376,19 @@ read/write processing.
 .Sh ENVIRONMENT
 The following environment variables affect the execution of the allocation
 functions:
-.Bl -tag -width ".Ev JEMALLOC_OPTIONS"
+@roff_prof@.Bl -tag -width ".Ev JEMALLOC_PROF_PREFIX"
+@roff_no_prof@.Bl -tag -width ".Ev JEMALLOC_OPTIONS"
 .It Ev JEMALLOC_OPTIONS
 If the environment variable
 .Ev JEMALLOC_OPTIONS
 is set, the characters it contains will be interpreted as flags to the
 allocation functions.
+@roff_prof@.It Ev JEMALLOC_PROF_PREFIX
+@roff_prof@If the environment variable
+@roff_prof@.Ev JEMALLOC_PROF_PREFIX
+@roff_prof@is set, use itas the filename prefix for profile dumps; otherwise use
+@roff_prof@.Pa jeprof
+@roff_prof@as the prefix.
 .El
 .Sh EXAMPLES
 To dump core whenever a problem occurs:
diff --git a/jemalloc/src/prof.c b/jemalloc/src/prof.c
index f471c6a1..8f69c01f 100644
--- a/jemalloc/src/prof.c
+++ b/jemalloc/src/prof.c
@@ -854,13 +854,12 @@ prof_dump(const char *filename, bool leakcheck)
 	}
 }
 
-/*                               jeprof.<pid>.<seq>.v<vseq>.heap\0     */
-#define	DUMP_FILENAME_BUFSIZE	(7	+ UMAX2S_BUFSIZE		\
-					     + 1			\
-					      + UMAX2S_BUFSIZE		\
-						   + 2			\
-						     + UMAX2S_BUFSIZE	\
-						           + 5  + 1)
+#define	DUMP_FILENAME_BUFSIZE	(PATH_MAX+ UMAX2S_BUFSIZE		\
+					       + 1			\
+						+ UMAX2S_BUFSIZE	\
+						     + 2		\
+						       + UMAX2S_BUFSIZE	\
+						             + 5  + 1)
 static void
 prof_dump_filename(char *filename, char v, int64_t vseq)
 {
@@ -868,9 +867,30 @@ prof_dump_filename(char *filename, char v, int64_t vseq)
 	char *s;
 	unsigned i, slen;
 
+	/*
+	 * Construct a filename of the form:
+	 *
+	 *   <prefix>.<pid>.<seq>.v<vseq>.heap\0
+	 * or
+	 *   jeprof.<pid>.<seq>.v<vseq>.heap\0
+	 */
+
 	i = 0;
 
-	s = "jeprof.";
+	/*
+	 * Use JEMALLOC_PROF_PREFIX if it's set, and if it is short enough to
+	 * avoid overflowing DUMP_FILENAME_BUFSIZE.  The result may exceed
+	 * PATH_MAX, but creat(2) will catch that problem.
+	 */
+	if ((s = getenv("JEMALLOC_PROF_PREFIX")) != NULL
+	    && strlen(s) + (DUMP_FILENAME_BUFSIZE - PATH_MAX) <= PATH_MAX) {
+		slen = strlen(s);
+		memcpy(&filename[i], s, slen);
+		i += slen;
+
+		s = ".";
+	} else
+		s = "jeprof.";
 	slen = strlen(s);
 	memcpy(&filename[i], s, slen);
 	i += slen;