Index: usr.sbin/pmcstat/pmcpl_gprof.c
===================================================================
--- usr.sbin/pmcstat/pmcpl_gprof.c
+++ usr.sbin/pmcstat/pmcpl_gprof.c
@@ -74,6 +74,14 @@
 #include "pmcpl_callgraph.h"
 #include "pmcpl_gprof.h"
 
+typedef	uint64_t	WIDEHISTCOUNTER;
+
+#define	WIDEHISTCOUNTER_MAX		UINT64_MAX
+#define	HISTCOUNTER_MAX			USHRT_MAX
+#define	WIDEHISTCOUNTER_GMONTYPE	((int) 64)
+#define	HISTCOUNTER_GMONTYPE		((int) 0)
+static int hc_sz=0;
+
 /*
  * struct pmcstat_gmonfile tracks a given 'gmon.out' file.  These
  * files are mmap()'ed in as needed.
@@ -126,11 +134,13 @@
 
 	gm.lpc = image->pi_start;
 	gm.hpc = image->pi_end;
-	gm.ncnt = (pgf->pgf_nbuckets * sizeof(HISTCOUNTER)) +
-	    sizeof(struct gmonhdr);
+	gm.ncnt = (pgf->pgf_nbuckets * hc_sz) + sizeof(struct gmonhdr);
 	gm.version = GMONVERSION;
 	gm.profrate = 0;		/* use ticks */
-	gm.histcounter_type = 0;	/* compatibility with moncontrol() */
+	if (args.pa_flags & FLAG_DO_WIDE_GPROF_HC)
+		gm.histcounter_type = WIDEHISTCOUNTER_GMONTYPE;
+	else
+		gm.histcounter_type = HISTCOUNTER_GMONTYPE;;
 	gm.spare[0] = gm.spare[1] = 0;
 
 	/* Write out the gmon header */
@@ -400,6 +410,7 @@
 	struct pmcstat_gmonfile *pgf;
 	uintfptr_t bucket;
 	HISTCOUNTER *hc;
+	WIDEHISTCOUNTER *whc;
 	pmc_id_t pmcid;
 
 	(void) nsamples; (void) usermode; (void) cpu;
@@ -437,6 +448,14 @@
 	 */
 	pgf = pmcstat_image_find_gmonfile(image, pmcid);
 	if (pgf == NULL) {
+		if (hc_sz == 0) {
+			/* Determine the correct histcounter size. */
+			if (args.pa_flags & FLAG_DO_WIDE_GPROF_HC)
+				hc_sz = sizeof(WIDEHISTCOUNTER);
+			else
+				hc_sz = sizeof(HISTCOUNTER);
+		}
+
 		if ((pgf = calloc(1, sizeof(*pgf))) == NULL)
 			err(EX_OSERR, "ERROR:");
 
@@ -448,7 +467,7 @@
 		pgf->pgf_nbuckets = (image->pi_end - image->pi_start) /
 		    FUNCTION_ALIGNMENT;	/* see <machine/profile.h> */
 		pgf->pgf_ndatabytes = sizeof(struct gmonhdr) +
-		    pgf->pgf_nbuckets * sizeof(HISTCOUNTER);
+		    pgf->pgf_nbuckets * hc_sz;
 		pgf->pgf_nsamples = 0;
 		pgf->pgf_file = NULL;
 
@@ -474,14 +493,25 @@
 
 	assert(bucket < pgf->pgf_nbuckets);
 
-	hc = (HISTCOUNTER *) ((uintptr_t) pgf->pgf_gmondata +
-	    sizeof(struct gmonhdr));
-
-	/* saturating add */
-	if (hc[bucket] < 0xFFFFU)  /* XXX tie this to sizeof(HISTCOUNTER) */
-		hc[bucket]++;
-	else /* mark that an overflow occurred */
-		pgf->pgf_overflow = 1;
+	if (args.pa_flags & FLAG_DO_WIDE_GPROF_HC) {
+		whc = (WIDEHISTCOUNTER *) ((uintptr_t) pgf->pgf_gmondata +
+		    sizeof(struct gmonhdr));
+
+		/* saturating add */
+		if (whc[bucket] < WIDEHISTCOUNTER_MAX)
+			whc[bucket]++;
+		else /* mark that an overflow occurred */
+			pgf->pgf_overflow = 1;
+	} else {
+		hc = (HISTCOUNTER *) ((uintptr_t) pgf->pgf_gmondata +
+		    sizeof(struct gmonhdr));
+
+		/* saturating add */
+		if (hc[bucket] < HISTCOUNTER_MAX)
+			hc[bucket]++;
+		else /* mark that an overflow occurred */
+			pgf->pgf_overflow = 1;
+	}
 
 	pgf->pgf_nsamples++;
 }
Index: usr.sbin/pmcstat/pmcstat.h
===================================================================
--- usr.sbin/pmcstat/pmcstat.h
+++ usr.sbin/pmcstat/pmcstat.h
@@ -55,6 +55,7 @@
 #define	FLAG_DO_ANALYSIS		0x00020000	/* -g or -G or -m or -T */
 #define	FLAGS_HAS_CPUMASK		0x00040000	/* -c */
 #define	FLAG_HAS_DURATION		0x00080000	/* -l secs */
+#define	FLAG_DO_WIDE_GPROF_HC		0x00100000	/* -e */
 
 #define	DEFAULT_SAMPLE_COUNT		65536
 #define	DEFAULT_WAIT_INTERVAL		5.0
Index: usr.sbin/pmcstat/pmcstat.8
===================================================================
--- usr.sbin/pmcstat/pmcstat.8
+++ usr.sbin/pmcstat/pmcstat.8
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd May 27, 2015
+.Dd November 17, 2015
 .Dt PMCSTAT 8
 .Os
 .Sh NAME
@@ -49,6 +49,7 @@
 .Op Fl a Ar pathname
 .Op Fl c Ar cpu-spec
 .Op Fl d
+.Op Fl e
 .Op Fl f Ar pluginopt
 .Op Fl g
 .Op Fl k Ar kerneldir
@@ -260,6 +261,12 @@
 .Fl P ,
 or
 .Fl S ) .
+.It Fl e
+Specify that the gprof profile files will use a wide history counter.
+These files are produced in a format compatible with
+.Xr gprof 1 .
+However, other tools that cannot fully parse a BSD-style
+gmon header might be unable to correctly parse these files.
 .It Fl f Ar pluginopt
 Pass option string to the active plugin.
 .br
Index: usr.sbin/pmcstat/pmcstat.c
===================================================================
--- usr.sbin/pmcstat/pmcstat.c
+++ usr.sbin/pmcstat/pmcstat.c
@@ -506,6 +506,7 @@
 	    "\t -a file\t print sampled PCs and callgraph to \"file\"\n"
 	    "\t -c cpu-list\t set cpus for subsequent system-wide PMCs\n"
 	    "\t -d\t\t (toggle) track descendants\n"
+	    "\t -e\t\t use wide history counter for gprof(1) output\n"
 	    "\t -f spec\t pass \"spec\" to as plugin option\n"
 	    "\t -g\t\t produce gprof(1) compatible profiles\n"
 	    "\t -k dir\t\t set the path to the kernel\n"
@@ -627,7 +628,7 @@
 	CPU_COPY(&rootmask, &cpumask);
 
 	while ((option = getopt(argc, argv,
-	    "CD:EF:G:M:NO:P:R:S:TWa:c:df:gk:l:m:n:o:p:qr:s:t:vw:z:")) != -1)
+	    "CD:EF:G:M:NO:P:R:S:TWa:c:def:gk:l:m:n:o:p:qr:s:t:vw:z:")) != -1)
 		switch (option) {
 		case 'a':	/* Annotate + callgraph */
 			args.pa_flags |= FLAG_DO_ANNOTATE;
@@ -668,6 +669,10 @@
 			args.pa_required |= FLAG_HAS_PROCESS_PMCS;
 			break;
 
+		case 'e':	/* wide gprof metrics */
+			args.pa_flags |= FLAG_DO_WIDE_GPROF_HC;
+			break;
+
 		case 'F':	/* produce a system-wide calltree */
 			args.pa_flags |= FLAG_DO_CALLGRAPHS;
 			args.pa_plugin = PMCSTAT_PL_CALLTREE;
@@ -1022,6 +1027,13 @@
 "ERROR: options -g/-G/-m/-T require sampling PMCs or -R to be specified."
 		    );
 
+	/* check if -e was specified without -g */
+	if ((args.pa_flags & FLAG_DO_WIDE_GPROF_HC) &&
+	    !(args.pa_flags & FLAG_DO_GPROF))
+		errx(EX_USAGE,
+"ERROR: option -e requires gprof mode to be specified."
+		    );
+
 	/* check if -O was spuriously specified */
 	if ((args.pa_flags & FLAG_HAS_OUTPUT_LOGFILE) &&
 	    (args.pa_required & FLAG_HAS_OUTPUT_LOGFILE) == 0)