diff --git a/src/emu/CMakeLists.txt b/src/emu/CMakeLists.txt
index 6157f90..3bd09ac 100644
--- a/src/emu/CMakeLists.txt
+++ b/src/emu/CMakeLists.txt
@@ -28,6 +28,7 @@ add_library(emu STATIC
   path.c
   proc.c
   pv/pcf.c
+  pv/prf.c
   pv/prv.c
   pv/pvt.c
   recorder.c
diff --git a/src/emu/pv/prf.c b/src/emu/pv/prf.c
new file mode 100644
index 0000000..b92cf76
--- /dev/null
+++ b/src/emu/pv/prf.c
@@ -0,0 +1,80 @@
+#include "prf.h"
+
+#include <string.h>
+#include "common.h"
+
+int
+prf_open(struct prf *prf, const char *path, long nrows)
+{
+	memset(prf, 0, sizeof(*prf));
+
+	prf->f = fopen(path, "w");
+
+	if (prf->f == NULL) {
+		err("cannot open ROW file '%s':", path);
+		return -1;
+	}
+
+	prf->nrows = nrows;
+	prf->rows = calloc(nrows, sizeof(struct prf_row));
+
+	if (prf->rows == NULL) {
+		err("calloc failed:");
+		return -1;
+	}
+
+	return 0;
+}
+
+int
+prf_add(struct prf *prf, long index, const char *label)
+{
+	if (index < 0 || index >= prf->nrows) {
+		err("index out of bounds");
+		return -1;
+	}
+
+	struct prf_row *row = &prf->rows[index];
+	if (row->set) {
+		err("row %ld already set to '%s'", index, row->label);
+		return -1;
+	}
+
+	int n = snprintf(row->label, MAX_PRF_LABEL, "%s", label);
+
+	if (n >= MAX_PRF_LABEL) {
+		err("label '%s' too long", label);
+		return -1;
+	}
+
+	row->set = 1;
+	return 0;
+}
+
+int
+prf_close(struct prf *prf)
+{
+	for (long i = 0; i < prf->nrows; i++) {
+		struct prf_row *row = &prf->rows[i];
+		if (!row->set) {
+			err("row %ld not set", i);
+			return -1;
+		}
+	}
+
+	FILE *f = prf->f;
+	fprintf(f, "LEVEL NODE SIZE 1\n");
+	fprintf(f, "hostname\n");
+	fprintf(f, "\n");
+
+	fprintf(f, "LEVEL THREAD SIZE %ld\n", prf->nrows);
+
+	for (long i = 0; i < prf->nrows; i++) {
+		struct prf_row *row = &prf->rows[i];
+		fprintf(f, "%s\n", row->label);
+	}
+
+	fclose(f);
+
+	return 0;
+}
diff --git a/src/emu/pv/prf.h b/src/emu/pv/prf.h
new file mode 100644
index 0000000..d9101ff
--- /dev/null
+++ b/src/emu/pv/prf.h
@@ -0,0 +1,27 @@
+/* Copyright (c) 2021-2023 Barcelona Supercomputing Center (BSC)
+ * SPDX-License-Identifier: GPL-3.0-or-later */
+
+#ifndef PRF_H
+#define PRF_H
+
+#include <stdio.h>
+
+#define MAX_PRF_LABEL 512
+
+struct prf_row {
+	char label[MAX_PRF_LABEL];
+	int set;
+};
+
+struct prf {
+	FILE *f;
+	long nrows;
+	struct prf_row *rows;
+};
+
+int prf_open(struct prf *prf, const char *path, long nrows);
+int prf_add(struct prf *prf, long index, const char *name);
+int prf_close(struct prf *prf);
+
+
+#endif /* PRF_H */
diff --git a/src/emu/pv/pvt.c b/src/emu/pv/pvt.c
index 4bdf08e..bfba7de 100644
--- a/src/emu/pv/pvt.c
+++ b/src/emu/pv/pvt.c
@@ -37,6 +37,17 @@ pvt_open(struct pvt *pvt, long nrows, const char *dir, const char *name)
 		return -1;
 	}
 
+	char prfpath[PATH_MAX];
+	if (snprintf(prfpath, PATH_MAX, "%s/%s.row", dir, name) >= PATH_MAX) {
+		err("snprintf failed: path too long");
+		return -1;
+	}
+
+	if (prf_open(&pvt->prf, prfpath, nrows) != 0) {
+		err("prf_open failed");
+		return -1;
+	}
+
 	return 0;
 }
 
@@ -52,6 +63,12 @@ pvt_get_pcf(struct pvt *pvt)
 	return &pvt->pcf;
 }
 
+struct prf *
+pvt_get_prf(struct pvt *pvt)
+{
+	return &pvt->prf;
+}
+
 int
 pvt_advance(struct pvt *pvt, int64_t time)
 {
@@ -62,12 +79,17 @@ int
 pvt_close(struct pvt *pvt)
 {
 	if (prv_close(&pvt->prv) != 0) {
-		err("prv_close failed");
+		err("prv_close failed for '%s'", pvt->name);
 		return -1;
 	}
 
 	if (pcf_close(&pvt->pcf) != 0) {
-		err("pcf_close failed");
+		err("pcf_close failed for '%s'", pvt->name);
+		return -1;
+	}
+
+	if (prf_close(&pvt->prf) != 0) {
+		err("prf_close failed for '%s'", pvt->name);
 		return -1;
 	}
 
diff --git a/src/emu/pv/pvt.h b/src/emu/pv/pvt.h
index 2984f11..6ba40fc 100644
--- a/src/emu/pv/pvt.h
+++ b/src/emu/pv/pvt.h
@@ -6,6 +6,7 @@
 
 #include "prv.h"
 #include "pcf.h"
+#include "prf.h"
 #include "uthash.h"
 #include <linux/limits.h>
 
@@ -14,6 +15,7 @@ struct pvt {
 	char name[PATH_MAX]; /* Without .prv extension */
 	struct prv prv;
 	struct pcf pcf;
+	struct prf prf;
 
 	struct UT_hash_handle hh; /* For recorder */
 };
@@ -21,6 +23,7 @@ struct pvt {
 int pvt_open(struct pvt *pvt, long nrows, const char *dir, const char *name);
 struct prv *pvt_get_prv(struct pvt *pvt);
 struct pcf *pvt_get_pcf(struct pvt *pvt);
+struct prf *pvt_get_prf(struct pvt *pvt);
 int pvt_advance(struct pvt *pvt, int64_t time);
 int pvt_close(struct pvt *pvt);
 
diff --git a/src/emu/system.c b/src/emu/system.c
index 8cbfb74..4891993 100644
--- a/src/emu/system.c
+++ b/src/emu/system.c
@@ -533,11 +533,14 @@ int
 system_connect(struct system *sys, struct bay *bay, struct recorder *rec)
 {
 	/* Create Paraver traces */
-	if (recorder_add_pvt(rec, "cpu", sys->ncpus) == NULL) {
+	struct pvt *pvt_cpu = NULL;
+	if ((pvt_cpu = recorder_add_pvt(rec, "cpu", sys->ncpus)) == NULL) {
 		err("recorder_add_pvt failed");
 		return -1;
 	}
-	if (recorder_add_pvt(rec, "thread", sys->nthreads) == NULL) {
+
+	struct pvt *pvt_th = NULL;
+	if ((pvt_th = recorder_add_pvt(rec, "thread", sys->nthreads)) == NULL) {
 		err("recorder_add_pvt failed");
 		return -1;
 	}
@@ -547,6 +550,20 @@ system_connect(struct system *sys, struct bay *bay, struct recorder *rec)
 			err("thread_connect failed\n");
 			return -1;
 		}
+
+		struct prf *prf = pvt_get_prf(pvt_th);
+		char name[128];
+		int appid = th->proc->appid;
+		int tid = th->tid;
+		if (snprintf(name, 128, "TH %d.%d", appid, tid) >= 128) {
+			err("label too long");
+			return -1;
+		}
+
+		if (prf_add(prf, th->gindex, name) != 0) {
+			err("prf_add failed for thread '%s'", th->id);
+			return -1;
+		}
 	}
 
 	for (struct cpu *cpu = sys->cpus; cpu; cpu = cpu->next) {
@@ -554,6 +571,12 @@ system_connect(struct system *sys, struct bay *bay, struct recorder *rec)
 			err("cpu_connect failed\n");
 			return -1;
 		}
+
+		struct prf *prf = pvt_get_prf(pvt_cpu);
+		if (prf_add(prf, cpu->gindex, cpu->name) != 0) {
+			err("prf_add failed for cpu '%s'", cpu->name);
+			return -1;
+		}
 	}
 
 	return 0;