diff --git a/MAINTAINERS b/MAINTAINERS
index 1fe5df3afd..2550d950de 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -164,6 +164,7 @@ F: app/test/test_lcores.c
 F: app/test/test_logs.c
 F: app/test/test_memcpy*
 F: app/test/test_per_lcore.c
+F: app/test/test_pflock.c
 F: app/test/test_prefetch.c
 F: app/test/test_reciprocal_division*
 F: app/test/test_rwlock.c
diff --git a/app/test/meson.build b/app/test/meson.build
index 76eaaea457..bd50818f82 100644
--- a/app/test/meson.build
+++ b/app/test/meson.build
@@ -90,6 +90,7 @@ test_sources = files('commands.c',
 	'test_mcslock.c',
 	'test_mp_secondary.c',
 	'test_per_lcore.c',
+	'test_pflock.c',
 	'test_pmd_perf.c',
 	'test_power.c',
 	'test_power_cpufreq.c',
@@ -228,6 +229,7 @@ fast_tests = [
         ['meter_autotest', true],
         ['multiprocess_autotest', false],
         ['per_lcore_autotest', true],
+        ['pflock_autotest', true],
         ['prefetch_autotest', true],
         ['rcu_qsbr_autotest', true],
         ['red_autotest', true],
diff --git a/app/test/test_pflock.c b/app/test/test_pflock.c
new file mode 100644
index 0000000000..38da6bce27
--- /dev/null
+++ b/app/test/test_pflock.c
@@ -0,0 +1,196 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2021 Microsoft Corporation
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <inttypes.h>
+#include <unistd.h>
+#include <sys/queue.h>
+#include <string.h>
+
+#include <rte_common.h>
+#include <rte_memory.h>
+#include <rte_per_lcore.h>
+#include <rte_launch.h>
+#include <rte_pflock.h>
+#include <rte_eal.h>
+#include <rte_lcore.h>
+#include <rte_cycles.h>
+
+#include "test.h"
+
+/*
+ * phase-fair lock test
+ * ====================
+ * Provides UT for phase-fair lock API.
+ * Main concern is on functional testing, but also provides some
+ * performance measurements.
+ * Obviously for proper testing need to be executed with more than one lcore.
+ */
+
+static rte_pflock_t sl;
+static rte_pflock_t sl_tab[RTE_MAX_LCORE];
+static uint32_t synchro;
+
+static int
+test_pflock_per_core(__rte_unused void *arg)
+{
+	rte_pflock_write_lock(&sl);
+	printf("Global write lock taken on core %u\n", rte_lcore_id());
+	rte_pflock_write_unlock(&sl);
+
+	rte_pflock_write_lock(&sl_tab[rte_lcore_id()]);
+	printf("Hello from core %u !\n", rte_lcore_id());
+	rte_pflock_write_unlock(&sl_tab[rte_lcore_id()]);
+
+	rte_pflock_read_lock(&sl);
+	printf("Global read lock taken on core %u\n", rte_lcore_id());
+	rte_delay_ms(100);
+	printf("Release global read lock on core %u\n", rte_lcore_id());
+	rte_pflock_read_unlock(&sl);
+
+	return 0;
+}
+
+static rte_pflock_t lk = RTE_PFLOCK_INITIALIZER;
+static uint64_t time_count[RTE_MAX_LCORE] = {0};
+
+#define MAX_LOOP 10000
+
+static int
+load_loop_fn(void *arg)
+{
+	uint64_t time_diff = 0, begin;
+	uint64_t hz = rte_get_timer_hz();
+	uint64_t lcount = 0;
+	const int use_lock = *(int *)arg;
+	const unsigned int lcore = rte_lcore_id();
+
+	/* wait synchro for workers */
+	if (lcore != rte_get_main_lcore())
+		rte_wait_until_equal_32(&synchro, 1, __ATOMIC_RELAXED);
+
+	begin = rte_rdtsc_precise();
+	while (lcount < MAX_LOOP) {
+		if (use_lock)
+			rte_pflock_write_lock(&lk);
+		lcount++;
+		if (use_lock)
+			rte_pflock_write_unlock(&lk);
+
+		if (use_lock) {
+			rte_pflock_read_lock(&lk);
+			rte_pflock_read_unlock(&lk);
+		}
+	}
+
+	time_diff = rte_rdtsc_precise() - begin;
+	time_count[lcore] = time_diff * 1000000 / hz;
+	return 0;
+}
+
+static int
+test_pflock_perf(void)
+{
+	unsigned int i;
+	int lock = 0;
+	uint64_t total = 0;
+	const unsigned int lcore = rte_lcore_id();
+
+	printf("\nTest with no lock on single core...\n");
+	__atomic_store_n(&synchro, 1, __ATOMIC_RELAXED);
+	load_loop_fn(&lock);
+	printf("Core [%u] Cost Time = %"PRIu64" us\n",
+			lcore, time_count[lcore]);
+	memset(time_count, 0, sizeof(time_count));
+
+	printf("\nTest with phase-fair lock on single core...\n");
+	lock = 1;
+	__atomic_store_n(&synchro, 1, __ATOMIC_RELAXED);
+	load_loop_fn(&lock);
+	printf("Core [%u] Cost Time = %"PRIu64" us\n",
+			lcore, time_count[lcore]);
+	memset(time_count, 0, sizeof(time_count));
+
+	printf("\nPhase-fair test on %u cores...\n", rte_lcore_count());
+
+	/* clear synchro and start workers */
+	__atomic_store_n(&synchro, 0, __ATOMIC_RELAXED);
+	if (rte_eal_mp_remote_launch(load_loop_fn, &lock, SKIP_MAIN) < 0)
+		return -1;
+
+	/* start synchro and launch test on main */
+	__atomic_store_n(&synchro, 1, __ATOMIC_RELAXED);
+	load_loop_fn(&lock);
+
+	rte_eal_mp_wait_lcore();
+
+	RTE_LCORE_FOREACH(i) {
+		printf("Core [%u] cost time = %"PRIu64" us\n",
+			i, time_count[i]);
+		total += time_count[i];
+	}
+
+	printf("Total cost time = %"PRIu64" us\n", total);
+	memset(time_count, 0, sizeof(time_count));
+
+	return 0;
+}
+
+/*
+ * - There is a global pflock and a table of pflocks (one per lcore).
+ *
+ * - The test function takes all of these locks and launches the
+ *   ``test_pflock_per_core()`` function on each core (except the main).
+ *
+ *   - The function takes the global write lock, display something,
+ *     then releases the global lock.
+ *   - Then, it takes the per-lcore write lock, display something, and
+ *     releases the per-core lock.
+ *   - Finally, a read lock is taken during 100 ms, then released.
+ *
+ * - The main function unlocks the per-lcore locks sequentially and
+ *   waits between each lock. This triggers the display of a message
+ *   for each core, in the correct order.
+ *
+ *   Then, it tries to take the global write lock and display the last
+ *   message. The autotest script checks that the message order is correct.
+ */
+static int
+test_pflock(void)
+{
+	int i;
+
+	rte_pflock_init(&sl);
+	for (i = 0; i < RTE_MAX_LCORE; i++)
+		rte_pflock_init(&sl_tab[i]);
+
+	rte_pflock_write_lock(&sl);
+
+	RTE_LCORE_FOREACH_WORKER(i) {
+		rte_pflock_write_lock(&sl_tab[i]);
+		rte_eal_remote_launch(test_pflock_per_core, NULL, i);
+	}
+
+	rte_pflock_write_unlock(&sl);
+
+	RTE_LCORE_FOREACH_WORKER(i) {
+		rte_pflock_write_unlock(&sl_tab[i]);
+		rte_delay_ms(100);
+	}
+
+	rte_pflock_write_lock(&sl);
+	/* this message should be the last message of test */
+	printf("Global write lock taken on main core %u\n", rte_lcore_id());
+	rte_pflock_write_unlock(&sl);
+
+	rte_eal_mp_wait_lcore();
+
+	if (test_pflock_perf() < 0)
+		return -1;
+
+	return 0;
+}
+
+REGISTER_TEST_COMMAND(pflock_autotest, test_pflock);
diff --git a/doc/api/doxy-api-index.md b/doc/api/doxy-api-index.md
index a734430c16..1992107a03 100644
--- a/doc/api/doxy-api-index.md
+++ b/doc/api/doxy-api-index.md
@@ -72,6 +72,7 @@ The public API headers are grouped by topics:
 - **locks**:
   [atomic]             (@ref rte_atomic.h),
   [mcslock]            (@ref rte_mcslock.h),
+  [pflock]             (@ref rte_pflock.h),
   [rwlock]             (@ref rte_rwlock.h),
   [spinlock]           (@ref rte_spinlock.h),
   [ticketlock]         (@ref rte_ticketlock.h),
diff --git a/doc/guides/rel_notes/release_21_05.rst b/doc/guides/rel_notes/release_21_05.rst
index 9a666b629d..2e3bf5c95a 100644
--- a/doc/guides/rel_notes/release_21_05.rst
+++ b/doc/guides/rel_notes/release_21_05.rst
@@ -55,6 +55,11 @@ New Features
      Also, make sure to start the actual text at the margin.
      =======================================================
 
+* **Added phase-fair lock.**
+
+  Phase-fair lock provides fairness guarantees.
+  It has two ticket pools, one for readers and one for writers.
+
 * **Added support for Marvell CN10K SoC drivers.**
 
   Added Marvell CN10K SoC support. Marvell CN10K SoC are based on Octeon 10
diff --git a/lib/librte_eal/arm/include/meson.build b/lib/librte_eal/arm/include/meson.build
index 770766de1a..2c3cff61be 100644
--- a/lib/librte_eal/arm/include/meson.build
+++ b/lib/librte_eal/arm/include/meson.build
@@ -21,6 +21,7 @@ arch_headers = files(
 	'rte_pause_32.h',
 	'rte_pause_64.h',
 	'rte_pause.h',
+	'rte_pflock.h',
 	'rte_power_intrinsics.h',
 	'rte_prefetch_32.h',
 	'rte_prefetch_64.h',
diff --git a/lib/librte_eal/arm/include/rte_pflock.h b/lib/librte_eal/arm/include/rte_pflock.h
new file mode 100644
index 0000000000..bb9934eec4
--- /dev/null
+++ b/lib/librte_eal/arm/include/rte_pflock.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2021 Microsoft Corporation
+ */
+
+#ifndef _RTE_PFLOCK_ARM_H_
+#define _RTE_PFLOCK_ARM_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "generic/rte_pflock.h"
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _RTE_PFLOCK_ARM_H_ */
diff --git a/lib/librte_eal/include/generic/rte_pflock.h b/lib/librte_eal/include/generic/rte_pflock.h
new file mode 100644
index 0000000000..e57c179ef2
--- /dev/null
+++ b/lib/librte_eal/include/generic/rte_pflock.h
@@ -0,0 +1,205 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2021 Microsoft Corp.
+ * All rights reserved.
+ *
+ * Derived from Concurrency Kit
+ * Copyright 2011-2015 Samy Al Bahra.
+ */
+
+#ifndef _RTE_PFLOCK_H_
+#define _RTE_PFLOCK_H_
+
+/**
+ * @file
+ *
+ * Phase-fair locks
+ *
+ * This file defines an API for phase-fair reader writer locks,
+ * which is a variant of typical reader-writer locks that prevent
+ * starvation. In this type of lock, readers and writers alternate.
+ * This significantly reduces the worst-case blocking for readers and writers.
+ *
+ * This is an implementation derived from FreeBSD
+ * based on the work described in:
+ *    Brandenburg, B. and Anderson, J. 2010. Spin-Based
+ *    Reader-Writer Synchronization for Multiprocessor Real-Time Systems
+ *
+ * All locks must be initialised before use, and only initialised once.
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <rte_common.h>
+#include <rte_pause.h>
+
+/**
+ * The rte_pflock_t type.
+ */
+struct rte_pflock {
+	struct {
+		uint16_t in;
+		uint16_t out;
+	} rd, wr;
+};
+typedef struct rte_pflock rte_pflock_t;
+
+/*
+ * Allocation of bits to reader
+ *
+ * 15                 4 3 2 1 0
+ * +-------------------+---+-+-+
+ * | rin: reads issued |x|x| | |
+ * +-------------------+---+-+-+
+ *                          ^ ^
+ *                          | |
+ * PRES: writer present ----/ |
+ * PHID: writer phase id -----/
+ *
+ * 15                4 3 2 1 0
+ * +------------------+------+
+ * |rout:read complete|unused|
+ * +------------------+------+
+ *
+ * The maximum number of readers is 4095
+ */
+
+/* Constants used to map the bits in reader counter */
+#define RTE_PFLOCK_WBITS 0x3	/* Writer bits in reader. */
+#define RTE_PFLOCK_PRES  0x2	/* Writer present bit. */
+#define RTE_PFLOCK_PHID  0x1	/* Phase ID bit. */
+#define RTE_PFLOCK_LSB   0xFFF0 /* reader bits. */
+#define RTE_PFLOCK_RINC  0x10	/* Reader increment. */
+
+/**
+ * A static pflock initializer.
+ */
+#define RTE_PFLOCK_INITIALIZER {  }
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Initialize the pflock to an unlocked state.
+ *
+ * @param pf
+ *   A pointer to the pflock.
+ */
+__rte_experimental
+static inline void
+rte_pflock_init(struct rte_pflock *pf)
+{
+	pf->rd.in = 0;
+	pf->rd.out = 0;
+	pf->wr.in = 0;
+	pf->wr.out = 0;
+}
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Take a pflock for read.
+ *
+ * @param pf
+ *   A pointer to a pflock structure.
+ */
+__rte_experimental
+static inline void
+rte_pflock_read_lock(rte_pflock_t *pf)
+{
+	uint16_t w;
+
+	/*
+	 * If no writer is present, then the operation has completed
+	 * successfully.
+	 */
+	w = __atomic_fetch_add(&pf->rd.in, RTE_PFLOCK_RINC, __ATOMIC_ACQUIRE)
+		& RTE_PFLOCK_WBITS;
+	if (w == 0)
+		return;
+
+	/* Wait for current write phase to complete. */
+	while ((__atomic_load_n(&pf->rd.in, __ATOMIC_ACQUIRE)
+		& RTE_PFLOCK_WBITS) == w)
+		rte_pause();
+}
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Release a pflock locked for reading.
+ *
+ * @param pf
+ *   A pointer to the pflock structure.
+ */
+__rte_experimental
+static inline void
+rte_pflock_read_unlock(rte_pflock_t *pf)
+{
+	__atomic_fetch_add(&pf->rd.out, RTE_PFLOCK_RINC, __ATOMIC_RELEASE);
+}
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Take the pflock for write.
+ *
+ * @param pf
+ *   A pointer to the pflock structure.
+ */
+__rte_experimental
+static inline void
+rte_pflock_write_lock(rte_pflock_t *pf)
+{
+	uint16_t ticket, w;
+
+	/* Acquire ownership of write-phase.
+	 * This is same as rte_tickelock_lock().
+	 */
+	ticket = __atomic_fetch_add(&pf->wr.in, 1, __ATOMIC_RELAXED);
+	rte_wait_until_equal_16(&pf->wr.out, ticket, __ATOMIC_ACQUIRE);
+
+	/*
+	 * Acquire ticket on read-side in order to allow them
+	 * to flush. Indicates to any incoming reader that a
+	 * write-phase is pending.
+	 *
+	 * The load of rd.out in wait loop could be executed
+	 * speculatively.
+	 */
+	w = RTE_PFLOCK_PRES | (ticket & RTE_PFLOCK_PHID);
+	ticket = __atomic_fetch_add(&pf->rd.in, w, __ATOMIC_RELAXED);
+
+	/* Wait for any pending readers to flush. */
+	rte_wait_until_equal_16(&pf->rd.out, ticket, __ATOMIC_ACQUIRE);
+}
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Release a pflock held for writing.
+ *
+ * @param pf
+ *   A pointer to a pflock structure.
+ */
+__rte_experimental
+static inline void
+rte_pflock_write_unlock(rte_pflock_t *pf)
+{
+	/* Migrate from write phase to read phase. */
+	__atomic_fetch_and(&pf->rd.in, RTE_PFLOCK_LSB, __ATOMIC_RELEASE);
+
+	/* Allow other writers to continue. */
+	__atomic_fetch_add(&pf->wr.out, 1, __ATOMIC_RELEASE);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* RTE_PFLOCK_H */
diff --git a/lib/librte_eal/ppc/include/meson.build b/lib/librte_eal/ppc/include/meson.build
index dae40ede54..7692a531cc 100644
--- a/lib/librte_eal/ppc/include/meson.build
+++ b/lib/librte_eal/ppc/include/meson.build
@@ -11,6 +11,7 @@ arch_headers = files(
 	'rte_mcslock.h',
 	'rte_memcpy.h',
 	'rte_pause.h',
+	'rte_pflock.h',
 	'rte_power_intrinsics.h',
 	'rte_prefetch.h',
 	'rte_rwlock.h',
diff --git a/lib/librte_eal/ppc/include/rte_pflock.h b/lib/librte_eal/ppc/include/rte_pflock.h
new file mode 100644
index 0000000000..27c201b11d
--- /dev/null
+++ b/lib/librte_eal/ppc/include/rte_pflock.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2021 Microsoft Corporation
+ */
+#ifndef _RTE_PFLOCK_PPC_64_H_
+#define _RTE_PFLOCK_PPC_64_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "generic/rte_pflock.h"
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _RTE_PFLOCK_PPC_64_H_ */
diff --git a/lib/librte_eal/x86/include/meson.build b/lib/librte_eal/x86/include/meson.build
index 1a6ad0b173..f43645c208 100644
--- a/lib/librte_eal/x86/include/meson.build
+++ b/lib/librte_eal/x86/include/meson.build
@@ -10,6 +10,7 @@ arch_headers = files(
 	'rte_mcslock.h',
 	'rte_memcpy.h',
 	'rte_pause.h',
+	'rte_pflock.h',
 	'rte_power_intrinsics.h',
 	'rte_prefetch.h',
 	'rte_rtm.h',
diff --git a/lib/librte_eal/x86/include/rte_pflock.h b/lib/librte_eal/x86/include/rte_pflock.h
new file mode 100644
index 0000000000..c2d876062c
--- /dev/null
+++ b/lib/librte_eal/x86/include/rte_pflock.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2021 Microsoft Corporation
+ */
+
+#ifndef _RTE_PFLOCK_X86_64_H_
+#define _RTE_PFLOCK_X86_64_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "generic/rte_pflock.h"
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _RTE_PFLOCK_X86_64_H_ */