From 63af6fcfe1fd9b53a4ea045232bbd3913afaca3a Mon Sep 17 00:00:00 2001 From: Roman Dementiev Date: Fri, 19 Jun 2015 13:08:22 +0200 Subject: [PATCH] rwlock: add HTM lock elision for x86 This patch adds methods that use hardware memory transactions (HTM) on fast-path for rwlock (a.k.a. lock elision). Here the methods are implemented for x86 using Restricted Transactional Memory instructions (Intel(r) Transactional Synchronization Extensions). The implementation fall-backs to the normal rwlock if HTM is not available or memory transactions fail. This is not a replacement for all rwlock usages since not all critical sections protected by locks are friendly to HTM. For example, an attempt to perform a HW I/O operation inside a hardware memory transaction always aborts the transaction since the CPU is not able to roll-back should the transaction fail. Therefore, hardware transactional locks are not advised to be used around rte_eth_rx_burst() and rte_eth_tx_burst() calls. Signed-off-by: Roman Dementiev Acked-by: Bruce Richardson --- lib/librte_eal/common/Makefile | 4 +- .../common/include/arch/ppc_64/rte_rwlock.h | 38 +++++++++ .../common/include/arch/x86/rte_rwlock.h | 82 +++++++++++++++++++ .../common/include/{ => generic}/rte_rwlock.h | 50 +++++++++++ 4 files changed, 172 insertions(+), 2 deletions(-) create mode 100644 lib/librte_eal/common/include/arch/ppc_64/rte_rwlock.h create mode 100644 lib/librte_eal/common/include/arch/x86/rte_rwlock.h rename lib/librte_eal/common/include/{ => generic}/rte_rwlock.h (70%) diff --git a/lib/librte_eal/common/Makefile b/lib/librte_eal/common/Makefile index 3ea3bbf9dc..38772d4e1b 100644 --- a/lib/librte_eal/common/Makefile +++ b/lib/librte_eal/common/Makefile @@ -35,7 +35,7 @@ INC := rte_branch_prediction.h rte_common.h INC += rte_debug.h rte_eal.h rte_errno.h rte_launch.h rte_lcore.h INC += rte_log.h rte_memory.h rte_memzone.h rte_pci.h INC += rte_pci_dev_ids.h rte_per_lcore.h rte_random.h -INC += rte_rwlock.h rte_tailq.h rte_interrupts.h rte_alarm.h +INC += rte_tailq.h rte_interrupts.h rte_alarm.h INC += rte_string_fns.h rte_version.h INC += rte_eal_memconfig.h rte_malloc_heap.h INC += rte_hexdump.h rte_devargs.h rte_dev.h @@ -46,7 +46,7 @@ INC += rte_warnings.h endif 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 +GENERIC_INC += rte_spinlock.h rte_memcpy.h rte_cpuflags.h rte_rwlock.h # defined in mk/arch/$(RTE_ARCH)/rte.vars.mk ARCH_DIR ?= $(RTE_ARCH) ARCH_INC := $(notdir $(wildcard $(RTE_SDK)/lib/librte_eal/common/include/arch/$(ARCH_DIR)/*.h)) diff --git a/lib/librte_eal/common/include/arch/ppc_64/rte_rwlock.h b/lib/librte_eal/common/include/arch/ppc_64/rte_rwlock.h new file mode 100644 index 0000000000..de8af19e73 --- /dev/null +++ b/lib/librte_eal/common/include/arch/ppc_64/rte_rwlock.h @@ -0,0 +1,38 @@ +#ifndef _RTE_RWLOCK_PPC_64_H_ +#define _RTE_RWLOCK_PPC_64_H_ + +#ifdef __cplusplus +extern "C" { +#endif + +#include "generic/rte_rwlock.h" + +static inline void +rte_rwlock_read_lock_tm(rte_rwlock_t *rwl) +{ + rte_rwlock_read_lock(rwl); +} + +static inline void +rte_rwlock_read_unlock_tm(rte_rwlock_t *rwl) +{ + rte_rwlock_read_unlock(rwl); +} + +static inline void +rte_rwlock_write_lock_tm(rte_rwlock_t *rwl) +{ + rte_rwlock_write_lock(rwl); +} + +static inline void +rte_rwlock_write_unlock_tm(rte_rwlock_t *rwl) +{ + rte_rwlock_write_unlock(rwl); +} + +#ifdef __cplusplus +} +#endif + +#endif /* _RTE_RWLOCK_PPC_64_H_ */ diff --git a/lib/librte_eal/common/include/arch/x86/rte_rwlock.h b/lib/librte_eal/common/include/arch/x86/rte_rwlock.h new file mode 100644 index 0000000000..afd1c3c242 --- /dev/null +++ b/lib/librte_eal/common/include/arch/x86/rte_rwlock.h @@ -0,0 +1,82 @@ +/*- + * BSD LICENSE + * + * Copyright(c) 2015 Intel Corporation. All rights reserved. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * * Neither the name of Intel Corporation nor the names of its + * contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#ifndef _RTE_RWLOCK_X86_64_H_ +#define _RTE_RWLOCK_X86_64_H_ + +#ifdef __cplusplus +extern "C" { +#endif + +#include "generic/rte_rwlock.h" +#include "rte_spinlock.h" + +static inline void +rte_rwlock_read_lock_tm(rte_rwlock_t *rwl) +{ + if (likely(rte_try_tm(&rwl->cnt))) + return; + rte_rwlock_read_lock(rwl); +} + +static inline void +rte_rwlock_read_unlock_tm(rte_rwlock_t *rwl) +{ + if (unlikely(rwl->cnt)) + rte_rwlock_read_unlock(rwl); + else + rte_xend(); +} + +static inline void +rte_rwlock_write_lock_tm(rte_rwlock_t *rwl) +{ + if (likely(rte_try_tm(&rwl->cnt))) + return; + rte_rwlock_write_lock(rwl); +} + +static inline void +rte_rwlock_write_unlock_tm(rte_rwlock_t *rwl) +{ + if (unlikely(rwl->cnt)) + rte_rwlock_write_unlock(rwl); + else + rte_xend(); +} + +#ifdef __cplusplus +} +#endif + +#endif /* _RTE_RWLOCK_X86_64_H_ */ diff --git a/lib/librte_eal/common/include/rte_rwlock.h b/lib/librte_eal/common/include/generic/rte_rwlock.h similarity index 70% rename from lib/librte_eal/common/include/rte_rwlock.h rename to lib/librte_eal/common/include/generic/rte_rwlock.h index 115731de4a..7a0fdc55c8 100644 --- a/lib/librte_eal/common/include/rte_rwlock.h +++ b/lib/librte_eal/common/include/generic/rte_rwlock.h @@ -151,6 +151,56 @@ rte_rwlock_write_unlock(rte_rwlock_t *rwl) rte_atomic32_inc((rte_atomic32_t *)(intptr_t)&rwl->cnt); } +/** + * Try to execute critical section in a hardware memory transaction, if it + * fails or not available take a read lock + * + * NOTE: An attempt to perform a HW I/O operation inside a hardware memory + * transaction always aborts the transaction since the CPU is not able to + * roll-back should the transaction fail. Therefore, hardware transactional + * locks are not advised to be used around rte_eth_rx_burst() and + * rte_eth_tx_burst() calls. + * + * @param rwl + * A pointer to a rwlock structure. + */ +static inline void +rte_rwlock_read_lock_tm(rte_rwlock_t *rwl); + +/** + * Commit hardware memory transaction or release the read lock if the lock is used as a fall-back + * + * @param rwl + * A pointer to the rwlock structure. + */ +static inline void +rte_rwlock_read_unlock_tm(rte_rwlock_t *rwl); + +/** + * Try to execute critical section in a hardware memory transaction, if it + * fails or not available take a write lock + * + * NOTE: An attempt to perform a HW I/O operation inside a hardware memory + * transaction always aborts the transaction since the CPU is not able to + * roll-back should the transaction fail. Therefore, hardware transactional + * locks are not advised to be used around rte_eth_rx_burst() and + * rte_eth_tx_burst() calls. + * + * @param rwl + * A pointer to a rwlock structure. + */ +static inline void +rte_rwlock_write_lock_tm(rte_rwlock_t *rwl); + +/** + * Commit hardware memory transaction or release the write lock if the lock is used as a fall-back + * + * @param rwl + * A pointer to a rwlock structure. + */ +static inline void +rte_rwlock_write_unlock_tm(rte_rwlock_t *rwl); + #ifdef __cplusplus } #endif -- 2.20.1