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From: Joyce Kong <joyce.kong@arm.com>
To: dev@dpdk.org
Cc: nd@arm.com, thomas@monjalon.net, jerin.jacob@caviumnetworks.com,
	stephen@networkplumber.org, honnappa.nagarahalli@arm.com,
	gavin.hu@arm.com, Joyce kong <joyce.kong@arm.com>
Subject: [dpdk-dev] [PATCH v4 1/2] ticketlock: ticket based to improve fairness
Date: Tue, 19 Feb 2019 18:48:07 +0800	[thread overview]
Message-ID: <1550573288-148384-2-git-send-email-joyce.kong@arm.com> (raw)
In-Reply-To: <1550573288-148384-1-git-send-email-joyce.kong@arm.com>
In-Reply-To: <1548405441-60286-1-git-send-email-joyce.kong@arm.com>

The spinlock implementation is unfair, some threads may take locks
aggressively while leaving the other threads starving for long time.

This patch introduces ticketlock which gives each waiting thread a
ticket and they can take the lock one by one. First come, first serviced.
This avoids starvation for too long time and is more predictable.

Suggested-by: Jerin Jacob <jerinj@marvell.com>
Signed-off-by: Joyce kong <joyce.kong@arm.com>
Reviewed-by: Gavin Hu <gavin.hu@arm.com>
Reviewed-by: Ola Liljedahl <ola.liljedahl@arm.com>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
---
 MAINTAINERS                                        |   4 +
 doc/api/doxy-api-index.md                          |   1 +
 lib/librte_eal/common/Makefile                     |   2 +-
 .../common/include/generic/rte_ticketlock.h        | 201 +++++++++++++++++++++
 lib/librte_eal/common/meson.build                  |   1 +
 5 files changed, 208 insertions(+), 1 deletion(-)
 create mode 100644 lib/librte_eal/common/include/generic/rte_ticketlock.h

diff --git a/MAINTAINERS b/MAINTAINERS
index eef480a..022e6bb 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -212,6 +212,10 @@ M: Cristian Dumitrescu <cristian.dumitrescu@intel.com>
 F: lib/librte_eal/common/include/rte_bitmap.h
 F: test/test/test_bitmap.c
 
+Ticketlock
+M: Joyce Kong <joyce.kong@arm.com>
+F: lib/librte_eal/common/include/generic/rte_ticketlock.h
+
 ARM v7
 M: Jan Viktorin <viktorin@rehivetech.com>
 M: Gavin Hu <gavin.hu@arm.com>
diff --git a/doc/api/doxy-api-index.md b/doc/api/doxy-api-index.md
index d95ad56..aacc66b 100644
--- a/doc/api/doxy-api-index.md
+++ b/doc/api/doxy-api-index.md
@@ -65,6 +65,7 @@ The public API headers are grouped by topics:
   [atomic]             (@ref rte_atomic.h),
   [rwlock]             (@ref rte_rwlock.h),
   [spinlock]           (@ref rte_spinlock.h)
+  [ticketlock]         (@ref rte_ticketlock.h)
 
 - **CPU arch**:
   [branch prediction]  (@ref rte_branch_prediction.h),
diff --git a/lib/librte_eal/common/Makefile b/lib/librte_eal/common/Makefile
index 87d8c45..99e948b 100644
--- a/lib/librte_eal/common/Makefile
+++ b/lib/librte_eal/common/Makefile
@@ -20,7 +20,7 @@ INC += rte_bitmap.h rte_vfio.h rte_hypervisor.h rte_test.h
 INC += rte_reciprocal.h rte_fbarray.h rte_uuid.h
 
 GENERIC_INC := rte_atomic.h rte_byteorder.h rte_cycles.h rte_prefetch.h
-GENERIC_INC += rte_spinlock.h rte_memcpy.h rte_cpuflags.h rte_rwlock.h
+GENERIC_INC += rte_spinlock.h rte_memcpy.h rte_cpuflags.h rte_rwlock.h rte_ticketlock.h
 GENERIC_INC += rte_vect.h rte_pause.h rte_io.h
 
 # defined in mk/arch/$(RTE_ARCH)/rte.vars.mk
diff --git a/lib/librte_eal/common/include/generic/rte_ticketlock.h b/lib/librte_eal/common/include/generic/rte_ticketlock.h
new file mode 100644
index 0000000..4846962
--- /dev/null
+++ b/lib/librte_eal/common/include/generic/rte_ticketlock.h
@@ -0,0 +1,201 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2018-2019 Arm Limited
+ */
+
+#ifndef _RTE_TICKETLOCK_H_
+#define _RTE_TICKETLOCK_H_
+
+/**
+ * @file
+ *
+ * RTE ticket locks
+ *
+ * This file defines an API for ticket locks, which give each waiting
+ * thread a ticket and take the lock one by one, first come, first
+ * serviced.
+ *
+ * All locks must be initialised before use, and only initialised once.
+ *
+ */
+
+#include <rte_lcore.h>
+#include <rte_common.h>
+#include <rte_pause.h>
+
+/**
+ * The rte_ticketlock_t type.
+ */
+typedef struct {
+	unsigned int current;
+	unsigned int next;
+} rte_ticketlock_t;
+
+/**
+ * A static ticketlock initializer.
+ */
+#define RTE_TICKETLOCK_INITIALIZER { 0 }
+
+/**
+ * Initialize the ticketlock to an unlocked state.
+ *
+ * @param tl
+ *   A pointer to the ticketlock.
+ */
+static inline __rte_experimental void
+rte_ticketlock_init(rte_ticketlock_t *tl)
+{
+	__atomic_store_n(&tl->current, 0, __ATOMIC_RELAXED);
+	__atomic_store_n(&tl->next, 0, __ATOMIC_RELAXED);
+}
+
+/**
+ * Take the ticketlock.
+ *
+ * @param tl
+ *   A pointer to the ticketlock.
+ */
+static inline __rte_experimental void
+rte_ticketlock_lock(rte_ticketlock_t *tl)
+{
+	unsigned int me = __atomic_fetch_add(&tl->next, 1, __ATOMIC_RELAXED);
+	while (__atomic_load_n(&tl->current, __ATOMIC_ACQUIRE) != me)
+		rte_pause();
+}
+
+/**
+ * Release the ticketlock.
+ *
+ * @param tl
+ *   A pointer to the ticketlock.
+ */
+static inline __rte_experimental void
+rte_ticketlock_unlock(rte_ticketlock_t *tl)
+{
+	unsigned int i = __atomic_load_n(&tl->current, __ATOMIC_RELAXED);
+	i++;
+	__atomic_store_n(&tl->current, i, __ATOMIC_RELEASE);
+}
+
+/**
+ * Try to take the lock.
+ *
+ * @param tl
+ *   A pointer to the ticketlock.
+ * @return
+ *   1 if the lock is successfully taken; 0 otherwise.
+ */
+static inline __rte_experimental int
+rte_ticketlock_trylock(rte_ticketlock_t *tl)
+{
+	unsigned int next = __atomic_load_n(&tl->next, __ATOMIC_RELAXED);
+	unsigned int cur = __atomic_load_n(&tl->current, __ATOMIC_RELAXED);
+	if (next == cur) {
+		if (__atomic_compare_exchange_n(&tl->next, &next, next+1,
+			0, __ATOMIC_ACQUIRE, __ATOMIC_RELAXED))
+			return 1;
+	}
+
+	return 0;
+}
+
+/**
+ * Test if the lock is taken.
+ *
+ * @param tl
+ *   A pointer to the ticketlock.
+ * @return
+ *   1 if the lock icurrently taken; 0 otherwise.
+ */
+static inline __rte_experimental int
+rte_ticketlock_is_locked(rte_ticketlock_t *tl)
+{
+	return (__atomic_load_n(&tl->current, __ATOMIC_ACQUIRE) !=
+			__atomic_load_n(&tl->next, __ATOMIC_ACQUIRE));
+}
+
+/**
+ * The rte_ticketlock_recursive_t type.
+ */
+#define TICKET_LOCK_INVALID_ID -1
+
+typedef struct {
+	rte_ticketlock_t tl; /**< the actual ticketlock */
+	int user; /**< core id using lock, TICKET_LOCK_INVALID_ID for unused */
+	unsigned int count; /**< count of time this lock has been called */
+} rte_ticketlock_recursive_t;
+
+/**
+ * A static recursive ticketlock initializer.
+ */
+#define RTE_TICKETLOCK_RECURSIVE_INITIALIZER {RTE_TICKETLOCK_INITIALIZER, -1, 0}
+
+/**
+ * Initialize the recursive ticketlock to an unlocked state.
+ *
+ * @param tlr
+ *   A pointer to the recursive ticketlock.
+ */
+static inline __rte_experimental void
+rte_ticketlock_recursive_init(rte_ticketlock_recursive_t *tlr)
+{
+	rte_ticketlock_init(&tlr->tl);
+	__atomic_store_n(&tlr->user, TICKET_LOCK_INVALID_ID, __ATOMIC_RELAXED);
+	__atomic_store_n(&tlr->count, 0, __ATOMIC_RELAXED);
+}
+
+/**
+ * Take the recursive ticketlock.
+ *
+ * @param tlr
+ *   A pointer to the recursive ticketlock.
+ */
+static inline __rte_experimental void
+rte_ticketlock_recursive_lock(rte_ticketlock_recursive_t *tlr)
+{
+	int id = rte_gettid();
+
+	if (__atomic_load_n(&tlr->user, __ATOMIC_RELAXED) != id) {
+		rte_ticketlock_lock(&tlr->tl);
+		__atomic_store_n(&tlr->user, id, __ATOMIC_RELAXED);
+	}
+	tlr->count++;
+}
+
+/**
+ * Release the recursive ticketlock.
+ *
+ * @param tlr
+ *   A pointer to the recursive ticketlock.
+ */
+static inline __rte_experimental void
+rte_ticketlock_recursive_unlock(rte_ticketlock_recursive_t *tlr)
+{
+	if (--(tlr->count) == 0) {
+		__atomic_store_n(&tlr->user, TICKET_LOCK_INVALID_ID, __ATOMIC_RELAXED);
+		rte_ticketlock_unlock(&tlr->tl);
+	}
+}
+
+/**
+ * Try to take the recursive lock.
+ *
+ * @param tlr
+ *   A pointer to the recursive ticketlock.
+ * @return
+ *   1 if the lock is successfully taken; 0 otherwise.
+ */
+static inline __rte_experimental int
+rte_ticketlock_recursive_trylock(rte_ticketlock_recursive_t *tlr)
+{
+	int id = rte_gettid();
+
+	if (__atomic_load_n(&tlr->user, __ATOMIC_RELAXED) != id) {
+		if (rte_ticketlock_trylock(&tlr->tl) == 0)
+			return 0;
+		__atomic_store_n(&tlr->user, id, __ATOMIC_RELAXED);
+	}
+	tlr->count++;
+	return 1;
+}
+
+#endif /* _RTE_TICKETLOCK_H_ */
diff --git a/lib/librte_eal/common/meson.build b/lib/librte_eal/common/meson.build
index 2a10d57..23f9416 100644
--- a/lib/librte_eal/common/meson.build
+++ b/lib/librte_eal/common/meson.build
@@ -98,6 +98,7 @@ generic_headers = files(
 	'include/generic/rte_prefetch.h',
 	'include/generic/rte_rwlock.h',
 	'include/generic/rte_spinlock.h',
+	'include/generic/rte_ticketlock.h',
 	'include/generic/rte_vect.h')
 install_headers(generic_headers, subdir: 'generic')
 
-- 
2.7.4

  parent reply	other threads:[~2019-02-19 10:48 UTC|newest]

Thread overview: 74+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-13 14:46 [dpdk-dev] [PATCH v1] " Gavin Hu
2019-01-14  7:59 ` [dpdk-dev] [EXT] " Jerin Jacob Kollanukkaran
2019-01-14 16:57   ` Gavin Hu (Arm Technology China)
2019-01-14 23:36 ` [dpdk-dev] " Honnappa Nagarahalli
2019-01-18  9:15 ` [dpdk-dev] [PATCH v2 1/2] " Joyce Kong
2019-01-25  8:37   ` [dpdk-dev] [PATCH v3 0/2] ticketlock: implement ticketlock and add test case Joyce Kong
2019-02-19 10:48     ` [dpdk-dev] [PATCH v4 " Joyce Kong
2019-03-11  5:52       ` [dpdk-dev] [PATCH v5 " Joyce Kong
2019-02-19 10:48     ` Joyce Kong [this message]
2019-03-11  5:52       ` [dpdk-dev] [PATCH v5 1/2] eal/ticketlock: ticket based to improve fairness Joyce Kong
2019-03-13  9:41         ` Jerin Jacob Kollanukkaran
2019-03-15  6:57           ` Joyce Kong (Arm Technology China)
2019-03-15  6:57             ` Joyce Kong (Arm Technology China)
2019-03-13 15:36         ` Jerin Jacob Kollanukkaran
2019-03-15  6:58           ` Joyce Kong (Arm Technology China)
2019-03-15  6:58             ` Joyce Kong (Arm Technology China)
2019-02-19 10:48     ` [dpdk-dev] [PATCH v4 2/2] test/ticketlock: add ticket lock test case Joyce Kong
2019-03-11  5:52       ` [dpdk-dev] [PATCH v5 " Joyce Kong
2019-03-13 13:31         ` Jerin Jacob Kollanukkaran
2019-03-15  6:57           ` Joyce Kong (Arm Technology China)
2019-03-15  6:57             ` Joyce Kong (Arm Technology China)
2019-01-25  8:37   ` [dpdk-dev] [PATCH v3 1/2] ticketlock: ticket based to improve fairness Joyce Kong
2019-01-25  8:37   ` [dpdk-dev] [PATCH v3 2/2] test/ticketlock: add ticket lock test case Joyce Kong
2019-03-15  6:56   ` [dpdk-dev] [PATCH v6 0/2] ticketlock: implement ticketlock and add " Joyce Kong
2019-03-15  6:56     ` Joyce Kong
2019-03-15  6:56   ` [dpdk-dev] [PATCH v6 1/2] eal/ticketlock: ticket based to improve fairness Joyce Kong
2019-03-15  6:56     ` Joyce Kong
2019-03-15 12:55     ` Ananyev, Konstantin
2019-03-15 12:55       ` Ananyev, Konstantin
2019-03-19  9:44       ` Gavin Hu (Arm Technology China)
2019-03-19  9:44         ` Gavin Hu (Arm Technology China)
2019-03-19 10:15         ` Ananyev, Konstantin
2019-03-19 10:15           ` Ananyev, Konstantin
2019-03-20  5:11           ` Gavin Hu (Arm Technology China)
2019-03-20  5:11             ` Gavin Hu (Arm Technology China)
2019-03-20  9:47             ` Ananyev, Konstantin
2019-03-20  9:47               ` Ananyev, Konstantin
2019-03-22  2:04               ` Gavin Hu (Arm Technology China)
2019-03-22  2:04                 ` Gavin Hu (Arm Technology China)
2019-03-15  6:56   ` [dpdk-dev] [PATCH v6 2/2] test/ticketlock: add ticket lock test case Joyce Kong
2019-03-15  6:56     ` Joyce Kong
2019-03-21  9:13   ` [dpdk-dev] [PATCH v7 0/3] ticketlock: implement ticketlock and add " Joyce Kong
2019-03-21  9:13     ` Joyce Kong
2019-03-21  9:13   ` [dpdk-dev] [PATCH v7 2/3] eal/ticketlock: enable generic ticketlock on all arch Joyce Kong
2019-03-21  9:13     ` Joyce Kong
2019-03-21  9:13   ` [dpdk-dev] [PATCH v7 3/3] test/ticketlock: add ticket lock test case Joyce Kong
2019-03-21  9:13     ` Joyce Kong
2019-03-22 11:38     ` Ananyev, Konstantin
2019-03-22 11:38       ` Ananyev, Konstantin
2019-03-25 10:25       ` Joyce Kong (Arm Technology China)
2019-03-25 10:25         ` Joyce Kong (Arm Technology China)
2019-03-21  9:15   ` [dpdk-dev] [PATCH v7 1/3] eal/ticketlock: ticket based to improve fairness Joyce Kong
2019-03-21  9:15     ` Joyce Kong
2019-03-22 10:56     ` Ananyev, Konstantin
2019-03-22 10:56       ` Ananyev, Konstantin
2019-03-25 11:11   ` [dpdk-dev] [PATCH v8 0/3] ticketlock: implement ticketlock and add test case Joyce Kong
2019-03-25 11:11     ` Joyce Kong
2019-03-27 11:20     ` Ananyev, Konstantin
2019-03-27 11:20       ` Ananyev, Konstantin
2019-03-28 14:02       ` Thomas Monjalon
2019-03-28 14:02         ` Thomas Monjalon
2019-03-25 11:11   ` [dpdk-dev] [PATCH v8 1/3] eal/ticketlock: ticket based to improve fairness Joyce Kong
2019-03-25 11:11     ` Joyce Kong
2019-03-25 11:11   ` [dpdk-dev] [PATCH v8 2/3] eal/ticketlock: enable generic ticketlock on all arch Joyce Kong
2019-03-25 11:11     ` Joyce Kong
2019-03-25 11:11   ` [dpdk-dev] [PATCH v8 3/3] test/ticketlock: add ticket lock test case Joyce Kong
2019-03-25 11:11     ` Joyce Kong
2019-04-08 20:18     ` David Marchand
2019-04-08 20:18       ` David Marchand
2019-04-14 20:37       ` Thomas Monjalon
2019-04-14 20:37         ` Thomas Monjalon
2019-04-15  9:07         ` Joyce Kong (Arm Technology China)
2019-04-15  9:07           ` Joyce Kong (Arm Technology China)
2019-01-18  9:15 ` [dpdk-dev] [PATCH v2 2/2] " Joyce Kong

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