[dpdk-dev] [PATCH v5 2/2] mempool/ring: add support for new ring sync modes
Konstantin Ananyev
konstantin.ananyev at intel.com
Wed Jul 15 16:58:15 CEST 2020
Two new sync modes were introduced into rte_ring:
relaxed tail sync (RTS) and head/tail sync (HTS).
This change provides user with ability to select these
modes for ring based mempool via mempool ops API.
Signed-off-by: Konstantin Ananyev <konstantin.ananyev at intel.com>
Acked-by: Gage Eads <gage.eads at intel.com>
---
doc/guides/mempool/ring.rst | 22 ++++++-
doc/guides/prog_guide/ring_lib.rst | 8 +++
doc/guides/rel_notes/release_20_08.rst | 6 ++
drivers/mempool/ring/rte_mempool_ring.c | 88 ++++++++++++++++++++++---
4 files changed, 113 insertions(+), 11 deletions(-)
diff --git a/doc/guides/mempool/ring.rst b/doc/guides/mempool/ring.rst
index b8659c03f..ca03180ea 100644
--- a/doc/guides/mempool/ring.rst
+++ b/doc/guides/mempool/ring.rst
@@ -12,12 +12,14 @@ and can be selected via mempool ops API:
- ``ring_mp_mc``
Underlying **rte_ring** operates in multi-thread producer,
- multi-thread consumer sync mode.
+ multi-thread consumer sync mode. For more information please refer to:
+ :ref:`Ring_Library_MPMC_Mode`.
- ``ring_sp_sc``
Underlying **rte_ring** operates in single-thread producer,
- single-thread consumer sync mode.
+ single-thread consumer sync mode. For more information please refer to:
+ :ref:`Ring_Library_SPSC_Mode`.
- ``ring_sp_mc``
@@ -29,6 +31,22 @@ and can be selected via mempool ops API:
Underlying **rte_ring** operates in multi-thread producer,
single-thread consumer sync mode.
+- ``ring_mt_rts``
+
+ For underlying **rte_ring** both producer and consumer operate in
+ multi-thread Relaxed Tail Sync (RTS) mode. For more information please
+ refer to: :ref:`Ring_Library_MT_RTS_Mode`.
+
+- ``ring_mt_hts``
+
+ For underlying **rte_ring** both producer and consumer operate in
+ multi-thread Head-Tail Sync (HTS) mode. For more information please
+ refer to: :ref:`Ring_Library_MT_HTS_Mode`.
+
+For 'classic' DPDK deployments (with one thread per core) ``ring_mp_mc``
+mode is usually the most suitable and the fastest one. For overcommitted
+scenarios (multiple threads share same set of cores) ``ring_mt_rts`` or
+``ring_mt_hts`` usually provide a better alternative.
For more information about ``rte_ring`` structure, behaviour and available
synchronisation modes please refer to: :doc:`../prog_guide/ring_lib`.
diff --git a/doc/guides/prog_guide/ring_lib.rst b/doc/guides/prog_guide/ring_lib.rst
index f0a5a78b0..895484d95 100644
--- a/doc/guides/prog_guide/ring_lib.rst
+++ b/doc/guides/prog_guide/ring_lib.rst
@@ -359,6 +359,8 @@ That should help users to configure ring in the most suitable way for his
specific usage scenarios.
Currently supported modes:
+.. _Ring_Library_MPMC_Mode:
+
MP/MC (default one)
~~~~~~~~~~~~~~~~~~~
@@ -369,11 +371,15 @@ per core) this is usually the most suitable and fastest synchronization mode.
As a well known limitation - it can perform quite pure on some overcommitted
scenarios.
+.. _Ring_Library_SPSC_Mode:
+
SP/SC
~~~~~
Single-producer (/single-consumer) mode. In this mode only one thread at a time
is allowed to enqueue (/dequeue) objects to (/from) the ring.
+.. _Ring_Library_MT_RTS_Mode:
+
MP_RTS/MC_RTS
~~~~~~~~~~~~~
@@ -390,6 +396,8 @@ one for head update, second for tail update.
In comparison the original MP/MC algorithm requires one 32-bit CAS
for head update and waiting/spinning on tail value.
+.. _Ring_Library_MT_HTS_Mode:
+
MP_HTS/MC_HTS
~~~~~~~~~~~~~
diff --git a/doc/guides/rel_notes/release_20_08.rst b/doc/guides/rel_notes/release_20_08.rst
index 17d70e7c1..db25c6f9c 100644
--- a/doc/guides/rel_notes/release_20_08.rst
+++ b/doc/guides/rel_notes/release_20_08.rst
@@ -69,6 +69,12 @@ New Features
barriers. rte_*mb APIs, for ARMv8 platforms, are changed to use DMB
instruction to reflect this.
+* **Added support for new sync modes into mempool ring driver.**
+
+ Added ability to select new ring synchronisation modes:
+ ``relaxed tail sync (ring_mt_rts)`` and ``head/tail sync (ring_mt_hts)``
+ via mempool ops API.
+
* **Added the support for vfio-pci new VF token interface.**
From Linux 5.7, vfio-pci supports to bind both SR-IOV PF and the created VFs,
diff --git a/drivers/mempool/ring/rte_mempool_ring.c b/drivers/mempool/ring/rte_mempool_ring.c
index bc123fc52..b1f09ff28 100644
--- a/drivers/mempool/ring/rte_mempool_ring.c
+++ b/drivers/mempool/ring/rte_mempool_ring.c
@@ -25,6 +25,22 @@ common_ring_sp_enqueue(struct rte_mempool *mp, void * const *obj_table,
obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
}
+static int
+rts_ring_mp_enqueue(struct rte_mempool *mp, void * const *obj_table,
+ unsigned int n)
+{
+ return rte_ring_mp_rts_enqueue_bulk(mp->pool_data,
+ obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
+}
+
+static int
+hts_ring_mp_enqueue(struct rte_mempool *mp, void * const *obj_table,
+ unsigned int n)
+{
+ return rte_ring_mp_hts_enqueue_bulk(mp->pool_data,
+ obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
+}
+
static int
common_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned n)
{
@@ -39,17 +55,30 @@ common_ring_sc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned n)
obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
}
+static int
+rts_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned int n)
+{
+ return rte_ring_mc_rts_dequeue_bulk(mp->pool_data,
+ obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
+}
+
+static int
+hts_ring_mc_dequeue(struct rte_mempool *mp, void **obj_table, unsigned int n)
+{
+ return rte_ring_mc_hts_dequeue_bulk(mp->pool_data,
+ obj_table, n, NULL) == 0 ? -ENOBUFS : 0;
+}
+
static unsigned
common_ring_get_count(const struct rte_mempool *mp)
{
return rte_ring_count(mp->pool_data);
}
-
static int
-common_ring_alloc(struct rte_mempool *mp)
+ring_alloc(struct rte_mempool *mp, uint32_t rg_flags)
{
- int rg_flags = 0, ret;
+ int ret;
char rg_name[RTE_RING_NAMESIZE];
struct rte_ring *r;
@@ -60,12 +89,6 @@ common_ring_alloc(struct rte_mempool *mp)
return -rte_errno;
}
- /* ring flags */
- if (mp->flags & MEMPOOL_F_SP_PUT)
- rg_flags |= RING_F_SP_ENQ;
- if (mp->flags & MEMPOOL_F_SC_GET)
- rg_flags |= RING_F_SC_DEQ;
-
/*
* Allocate the ring that will be used to store objects.
* Ring functions will return appropriate errors if we are
@@ -82,6 +105,31 @@ common_ring_alloc(struct rte_mempool *mp)
return 0;
}
+static int
+common_ring_alloc(struct rte_mempool *mp)
+{
+ uint32_t rg_flags = 0;
+
+ if (mp->flags & MEMPOOL_F_SP_PUT)
+ rg_flags |= RING_F_SP_ENQ;
+ if (mp->flags & MEMPOOL_F_SC_GET)
+ rg_flags |= RING_F_SC_DEQ;
+
+ return ring_alloc(mp, rg_flags);
+}
+
+static int
+rts_ring_alloc(struct rte_mempool *mp)
+{
+ return ring_alloc(mp, RING_F_MP_RTS_ENQ | RING_F_MC_RTS_DEQ);
+}
+
+static int
+hts_ring_alloc(struct rte_mempool *mp)
+{
+ return ring_alloc(mp, RING_F_MP_HTS_ENQ | RING_F_MC_HTS_DEQ);
+}
+
static void
common_ring_free(struct rte_mempool *mp)
{
@@ -130,7 +178,29 @@ static const struct rte_mempool_ops ops_sp_mc = {
.get_count = common_ring_get_count,
};
+/* ops for mempool with ring in MT_RTS sync mode */
+static const struct rte_mempool_ops ops_mt_rts = {
+ .name = "ring_mt_rts",
+ .alloc = rts_ring_alloc,
+ .free = common_ring_free,
+ .enqueue = rts_ring_mp_enqueue,
+ .dequeue = rts_ring_mc_dequeue,
+ .get_count = common_ring_get_count,
+};
+
+/* ops for mempool with ring in MT_HTS sync mode */
+static const struct rte_mempool_ops ops_mt_hts = {
+ .name = "ring_mt_hts",
+ .alloc = hts_ring_alloc,
+ .free = common_ring_free,
+ .enqueue = hts_ring_mp_enqueue,
+ .dequeue = hts_ring_mc_dequeue,
+ .get_count = common_ring_get_count,
+};
+
MEMPOOL_REGISTER_OPS(ops_mp_mc);
MEMPOOL_REGISTER_OPS(ops_sp_sc);
MEMPOOL_REGISTER_OPS(ops_mp_sc);
MEMPOOL_REGISTER_OPS(ops_sp_mc);
+MEMPOOL_REGISTER_OPS(ops_mt_rts);
+MEMPOOL_REGISTER_OPS(ops_mt_hts);
--
2.17.1
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