> From: Liang Ma <liang.j...@intel.com> > > Add a simple on/off switch that will enable saving power when no > packets are arriving. It is based on counting the number of empty > polls and, when the number reaches a certain threshold, entering an > architecture-defined optimized power state that will either wait > until a TSC timestamp expires, or when packets arrive. > > This API mandates a core-to-single-queue mapping (that is, multiple > queued per device are supported, but they have to be polled on different > cores). > > This design is using PMD RX callbacks. > > 1. UMWAIT/UMONITOR: > > When a certain threshold of empty polls is reached, the core will go > into a power optimized sleep while waiting on an address of next RX > descriptor to be written to. > > 2. Pause instruction > > Instead of move the core into deeper C state, this method uses the > pause instruction to avoid busy polling. > > 3. Frequency scaling > Reuse existing DPDK power library to scale up/down core frequency > depending on traffic volume. > > Signed-off-by: Liang Ma <liang.j...@intel.com> > Signed-off-by: Anatoly Burakov <anatoly.bura...@intel.com> > --- > > Notes: > v6: > - Added wakeup mechanism for UMWAIT > - Removed memory allocation (everything is now allocated statically) > - Fixed various typos and comments > - Check for invalid queue ID > - Moved release notes to this patch > > v5: > - Make error checking more robust > - Prevent initializing scaling if ACPI or PSTATE env wasn't set > - Prevent initializing UMWAIT path if PMD doesn't support get_wake_addr > - Add some debug logging > - Replace x86-specific code path to generic path using the intrinsic check > > doc/guides/rel_notes/release_20_11.rst | 11 + > lib/librte_power/meson.build | 5 +- > lib/librte_power/rte_power_pmd_mgmt.c | 300 +++++++++++++++++++++++++ > lib/librte_power/rte_power_pmd_mgmt.h | 92 ++++++++ > lib/librte_power/rte_power_version.map | 4 + > 5 files changed, 410 insertions(+), 2 deletions(-) > create mode 100644 lib/librte_power/rte_power_pmd_mgmt.c > create mode 100644 lib/librte_power/rte_power_pmd_mgmt.h > > diff --git a/doc/guides/rel_notes/release_20_11.rst > b/doc/guides/rel_notes/release_20_11.rst > index ca4f43f7f9..06b822aa36 100644 > --- a/doc/guides/rel_notes/release_20_11.rst > +++ b/doc/guides/rel_notes/release_20_11.rst > @@ -197,6 +197,17 @@ New Features > * Added new ``RTE_ACL_CLASSIFY_AVX512X32`` vector implementation, > which can process up to 32 flows in parallel. Requires AVX512 support. > > +* **Add PMD power management mechanism** > + > + 3 new Ethernet PMD power management mechanism is added through existing > + RX callback infrastructure. > + > + * Add power saving scheme based on UMWAIT instruction (x86 only) > + * Add power saving scheme based on ``rte_pause()`` > + * Add power saving scheme based on frequency scaling through the power > library > + * Add new EXPERIMENTAL API ``rte_power_pmd_mgmt_queue_enable()`` > + * Add new EXPERIMENTAL API ``rte_power_pmd_mgmt_queue_disable()`` > + > > Removed Items > ------------- > diff --git a/lib/librte_power/meson.build b/lib/librte_power/meson.build > index 78c031c943..cc3c7a8646 100644 > --- a/lib/librte_power/meson.build > +++ b/lib/librte_power/meson.build > @@ -9,6 +9,7 @@ sources = files('rte_power.c', 'power_acpi_cpufreq.c', > 'power_kvm_vm.c', 'guest_channel.c', > 'rte_power_empty_poll.c', > 'power_pstate_cpufreq.c', > + 'rte_power_pmd_mgmt.c', > 'power_common.c') > -headers = files('rte_power.h','rte_power_empty_poll.h') > -deps += ['timer'] > +headers = > files('rte_power.h','rte_power_empty_poll.h','rte_power_pmd_mgmt.h') > +deps += ['timer' ,'ethdev'] > diff --git a/lib/librte_power/rte_power_pmd_mgmt.c > b/lib/librte_power/rte_power_pmd_mgmt.c > new file mode 100644 > index 0000000000..2b7d2a1a46 > --- /dev/null > +++ b/lib/librte_power/rte_power_pmd_mgmt.c > @@ -0,0 +1,300 @@ > +/* SPDX-License-Identifier: BSD-3-Clause > + * Copyright(c) 2010-2020 Intel Corporation > + */ > + > +#include <rte_lcore.h> > +#include <rte_cycles.h> > +#include <rte_cpuflags.h> > +#include <rte_malloc.h> > +#include <rte_ethdev.h> > +#include <rte_power_intrinsics.h> > + > +#include "rte_power_pmd_mgmt.h" > + > +#define EMPTYPOLL_MAX 512 > + > +/** > + * Possible power management states of an ethdev port. > + */ > +enum pmd_mgmt_state { > + /** Device power management is disabled. */ > + PMD_MGMT_DISABLED = 0, > + /** Device power management is enabled. */ > + PMD_MGMT_ENABLED, > +}; > + > +struct pmd_queue_cfg { > + enum pmd_mgmt_state pwr_mgmt_state; > + /**< State of power management for this queue */ > + enum rte_power_pmd_mgmt_type cb_mode; > + /**< Callback mode for this queue */ > + const struct rte_eth_rxtx_callback *cur_cb; > + /**< Callback instance */ > + rte_spinlock_t umwait_lock; > + /**< Per-queue status lock - used only for UMWAIT mode */ > + volatile void *wait_addr; > + /**< UMWAIT wakeup address */ > + uint64_t empty_poll_stats; > + /**< Number of empty polls */ > +} __rte_cache_aligned; > + > +static struct pmd_queue_cfg > port_cfg[RTE_MAX_ETHPORTS][RTE_MAX_QUEUES_PER_PORT]; > + > +/* trigger a write to the cache line we're waiting on */ > +static void umwait_wakeup(volatile void *addr) > +{ > + uint64_t val; > + > + val = __atomic_load_n((volatile uint64_t *)addr, __ATOMIC_RELAXED); > + __atomic_compare_exchange_n((volatile uint64_t *)addr, &val, val, 0, > + __ATOMIC_RELAXED, __ATOMIC_RELAXED); > +} > + > +static uint16_t > +clb_umwait(uint16_t port_id, uint16_t qidx, > + struct rte_mbuf **pkts __rte_unused, uint16_t nb_rx, > + uint16_t max_pkts __rte_unused, void *addr __rte_unused) > +{ > + > + struct pmd_queue_cfg *q_conf; > + > + q_conf = &port_cfg[port_id][qidx]; > + > + if (unlikely(nb_rx == 0)) { > + q_conf->empty_poll_stats++; > + if (unlikely(q_conf->empty_poll_stats > EMPTYPOLL_MAX)) { > + volatile void *target_addr; > + uint64_t expected, mask; > + uint16_t ret; > + uint8_t data_sz; > + > + /* > + * get address of next descriptor in the RX > + * ring for this queue, as well as expected > + * value and a mask. > + */ > + ret = rte_eth_get_wake_addr(port_id, qidx, > + &target_addr, &expected, &mask, > + &data_sz); > + if (ret == 0) { > + /* > + * we need to ensure we can wake up by another > + * thread triggering a write, so we need the > + * address to always be up to date. > + */ > + rte_spinlock_lock(&q_conf->umwait_lock);
I think you need to check state here, and _disable() have to set state with lock grabbed. Otherwise this lock wouldn't protect you from race conditions. As an example: CP@T0: rte_spinlock_lock(&queue_cfg->umwait_lock); if (queue_cfg->wait_addr != NULL) //wait_addr == NULL, fallthrough rte_spinlock_unlock(&queue_cfg->umwait_lock); DP@T1: rte_spinlock_lock(&queue_cfg->umwait_lock); queue_cfg->wait_addr = target_addr; monitor_sync(...); // DP was put to sleep CP@T2: queue_cfg->cur_cb = NULL; queue_cfg->pwr_mgmt_state = PMD_MGMT_DISABLED; ret = 0; rte_power_pmd_mgmt_queue_disable() finished with success, but DP core wasn't wokenup. To be more specific: clb_umwait(...) { ... lock(&qcfg->lck); if (qcfg->state == ENABLED) { qcfg->wake_addr = addr; monitor_sync(addr, ...,&qcfg->lck); } unlock(&qcfg->lck); ... } _disable(...) { ... lock(&qcfg->lck); qcfg->state = DISABLED; if (qcfg->wake_addr != NULL) monitor_wakeup(qcfg->wake_addr); unlock(&qcfg->lock); ... } > + q_conf->wait_addr = target_addr; > + /* -1ULL is maximum value for TSC */ > + rte_power_monitor_sync(target_addr, expected, > + mask, -1ULL, data_sz, > + &q_conf->umwait_lock); > + /* erase the address */ > + q_conf->wait_addr = NULL; > + rte_spinlock_unlock(&q_conf->umwait_lock); > + } > + } > + } else > + q_conf->empty_poll_stats = 0; > + > + return nb_rx; > +} > + > +static uint16_t > +clb_pause(uint16_t port_id, uint16_t qidx, > + struct rte_mbuf **pkts __rte_unused, uint16_t nb_rx, > + uint16_t max_pkts __rte_unused, void *addr __rte_unused) > +{ > + struct pmd_queue_cfg *q_conf; > + > + q_conf = &port_cfg[port_id][qidx]; > + > + if (unlikely(nb_rx == 0)) { > + q_conf->empty_poll_stats++; > + /* sleep for 1 microsecond */ > + if (unlikely(q_conf->empty_poll_stats > EMPTYPOLL_MAX)) > + rte_delay_us(1); > + } else > + q_conf->empty_poll_stats = 0; > + > + return nb_rx; > +} > + > +static uint16_t > +clb_scale_freq(uint16_t port_id, uint16_t qidx, > + struct rte_mbuf **pkts __rte_unused, uint16_t nb_rx, > + uint16_t max_pkts __rte_unused, void *_ __rte_unused) > +{ > + struct pmd_queue_cfg *q_conf; > + > + q_conf = &port_cfg[port_id][qidx]; > + > + if (unlikely(nb_rx == 0)) { > + q_conf->empty_poll_stats++; > + if (unlikely(q_conf->empty_poll_stats > EMPTYPOLL_MAX)) > + /* scale down freq */ > + rte_power_freq_min(rte_lcore_id()); > + } else { > + q_conf->empty_poll_stats = 0; > + /* scale up freq */ > + rte_power_freq_max(rte_lcore_id()); > + } > + > + return nb_rx; > +} > + > +int > +rte_power_pmd_mgmt_queue_enable(unsigned int lcore_id, > + uint16_t port_id, uint16_t queue_id, > + enum rte_power_pmd_mgmt_type mode) > +{ > + struct rte_eth_dev *dev; > + struct pmd_queue_cfg *queue_cfg; > + int ret; > + > + RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -EINVAL); > + dev = &rte_eth_devices[port_id]; > + > + /* check if queue id is valid */ > + if (queue_id >= dev->data->nb_rx_queues || > + queue_id >= RTE_MAX_QUEUES_PER_PORT) { > + return -EINVAL; > + } > + > + queue_cfg = &port_cfg[port_id][queue_id]; > + > + if (queue_cfg->pwr_mgmt_state == PMD_MGMT_ENABLED) { > + ret = -EINVAL; > + goto end; > + } > + > + switch (mode) { > + case RTE_POWER_MGMT_TYPE_WAIT: > + { > + /* check if rte_power_monitor is supported */ > + uint64_t dummy_expected, dummy_mask; > + struct rte_cpu_intrinsics i; > + volatile void *dummy_addr; > + uint8_t dummy_sz; > + > + rte_cpu_get_intrinsics_support(&i); > + > + if (!i.power_monitor) { > + RTE_LOG(DEBUG, POWER, "Monitoring intrinsics are not > supported\n"); > + ret = -ENOTSUP; > + goto end; > + } > + > + /* check if the device supports the necessary PMD API */ > + if (rte_eth_get_wake_addr(port_id, queue_id, > + &dummy_addr, &dummy_expected, > + &dummy_mask, &dummy_sz) == -ENOTSUP) { > + RTE_LOG(DEBUG, POWER, "The device does not support > rte_eth_rxq_ring_addr_get\n"); > + ret = -ENOTSUP; > + goto end; > + } > + /* initialize UMWAIT spinlock */ > + rte_spinlock_init(&queue_cfg->umwait_lock); I think don't need to do that. It supposed to be in valid state (otherwise you are probably in trouble anyway). > + > + /* initialize data before enabling the callback */ > + queue_cfg->empty_poll_stats = 0; > + queue_cfg->cb_mode = mode; > + queue_cfg->pwr_mgmt_state = PMD_MGMT_ENABLED; > + > + queue_cfg->cur_cb = rte_eth_add_rx_callback(port_id, queue_id, > + clb_umwait, NULL); Would be a bit cleaner/nicer to move add_rx_callback out of switch() {} As you have to do it always anyway. Same thought for disable() and remove_rx_callback(). > + break; > + } > + case RTE_POWER_MGMT_TYPE_SCALE: > + { > + enum power_management_env env; > + /* only PSTATE and ACPI modes are supported */ > + if (!rte_power_check_env_supported(PM_ENV_ACPI_CPUFREQ) && > + !rte_power_check_env_supported( > + PM_ENV_PSTATE_CPUFREQ)) { > + RTE_LOG(DEBUG, POWER, "Neither ACPI nor PSTATE modes > are supported\n"); > + ret = -ENOTSUP; > + goto end; > + } > + /* ensure we could initialize the power library */ > + if (rte_power_init(lcore_id)) { > + ret = -EINVAL; > + goto end; > + } > + /* ensure we initialized the correct env */ > + env = rte_power_get_env(); > + if (env != PM_ENV_ACPI_CPUFREQ && > + env != PM_ENV_PSTATE_CPUFREQ) { > + RTE_LOG(DEBUG, POWER, "Neither ACPI nor PSTATE modes > were initialized\n"); > + ret = -ENOTSUP; > + goto end; > + } > + /* initialize data before enabling the callback */ > + queue_cfg->empty_poll_stats = 0; > + queue_cfg->cb_mode = mode; > + queue_cfg->pwr_mgmt_state = PMD_MGMT_ENABLED; > + > + queue_cfg->cur_cb = rte_eth_add_rx_callback(port_id, > + queue_id, clb_scale_freq, NULL); > + break; > + } > + case RTE_POWER_MGMT_TYPE_PAUSE: > + /* initialize data before enabling the callback */ > + queue_cfg->empty_poll_stats = 0; > + queue_cfg->cb_mode = mode; > + queue_cfg->pwr_mgmt_state = PMD_MGMT_ENABLED; > + > + queue_cfg->cur_cb = rte_eth_add_rx_callback(port_id, queue_id, > + clb_pause, NULL); > + break; > + } > + ret = 0; > + > +end: > + return ret; > +} > + > +int > +rte_power_pmd_mgmt_queue_disable(unsigned int lcore_id, > + uint16_t port_id, uint16_t queue_id) > +{ > + struct pmd_queue_cfg *queue_cfg; > + int ret; > + > + queue_cfg = &port_cfg[port_id][queue_id]; > + > + if (queue_cfg->pwr_mgmt_state == PMD_MGMT_DISABLED) { > + ret = -EINVAL; > + goto end; > + } > + > + switch (queue_cfg->cb_mode) { > + case RTE_POWER_MGMT_TYPE_WAIT: > + rte_spinlock_lock(&queue_cfg->umwait_lock); > + > + /* wake up the core from UMWAIT sleep, if any */ > + if (queue_cfg->wait_addr != NULL) > + umwait_wakeup(queue_cfg->wait_addr); > + > + rte_spinlock_unlock(&queue_cfg->umwait_lock); > + /* fall-through */ > + case RTE_POWER_MGMT_TYPE_PAUSE: > + rte_eth_remove_rx_callback(port_id, queue_id, > + queue_cfg->cur_cb); > + break; > + case RTE_POWER_MGMT_TYPE_SCALE: > + rte_power_freq_max(lcore_id); > + rte_eth_remove_rx_callback(port_id, queue_id, > + queue_cfg->cur_cb); > + rte_power_exit(lcore_id); > + break; > + } > + /* > + * we don't free the RX callback here because it is unsafe to do so > + * unless we know for a fact that all data plane threads have stopped. > + */ > + queue_cfg->cur_cb = NULL; > + queue_cfg->pwr_mgmt_state = PMD_MGMT_DISABLED; > + ret = 0; > +end: > + return ret; > +} > diff --git a/lib/librte_power/rte_power_pmd_mgmt.h > b/lib/librte_power/rte_power_pmd_mgmt.h > new file mode 100644 > index 0000000000..a7a3f98268 > --- /dev/null > +++ b/lib/librte_power/rte_power_pmd_mgmt.h > @@ -0,0 +1,92 @@ > +/* SPDX-License-Identifier: BSD-3-Clause > + * Copyright(c) 2010-2020 Intel Corporation > + */ > + > +#ifndef _RTE_POWER_PMD_MGMT_H > +#define _RTE_POWER_PMD_MGMT_H > + > +/** > + * @file > + * RTE PMD Power Management > + */ > +#include <stdint.h> > +#include <stdbool.h> > + > +#include <rte_common.h> > +#include <rte_byteorder.h> > +#include <rte_log.h> > +#include <rte_power.h> > +#include <rte_atomic.h> > + > +#ifdef __cplusplus > +extern "C" { > +#endif > + > +/** > + * PMD Power Management Type > + */ > +enum rte_power_pmd_mgmt_type { > + /** WAIT callback mode. */ > + RTE_POWER_MGMT_TYPE_WAIT = 1, > + /** PAUSE callback mode. */ > + RTE_POWER_MGMT_TYPE_PAUSE, > + /** Freq Scaling callback mode. */ > + RTE_POWER_MGMT_TYPE_SCALE, > +}; > + > +/** > + * @warning > + * @b EXPERIMENTAL: this API may change, or be removed, without prior notice > + * > + * Setup per-queue power management callback. > + * > + * @note This function is not thread-safe. > + * > + * @param lcore_id > + * lcore_id. > + * @param port_id > + * The port identifier of the Ethernet device. > + * @param queue_id > + * The queue identifier of the Ethernet device. > + * @param mode > + * The power management callback function type. > + > + * @return > + * 0 on success > + * <0 on error > + */ > +__rte_experimental > +int > +rte_power_pmd_mgmt_queue_enable(unsigned int lcore_id, > + uint16_t port_id, > + uint16_t queue_id, > + enum rte_power_pmd_mgmt_type mode); > + > +/** > + * @warning > + * @b EXPERIMENTAL: this API may change, or be removed, without prior notice > + * > + * Remove per-queue power management callback. > + * > + * @note This function is not thread-safe. > + * > + * @param lcore_id > + * lcore_id. > + * @param port_id > + * The port identifier of the Ethernet device. > + * @param queue_id > + * The queue identifier of the Ethernet device. > + * @return > + * 0 on success > + * <0 on error > + */ > +__rte_experimental > +int > +rte_power_pmd_mgmt_queue_disable(unsigned int lcore_id, > + uint16_t port_id, > + uint16_t queue_id); > +#ifdef __cplusplus > +} > +#endif > + > +#endif > diff --git a/lib/librte_power/rte_power_version.map > b/lib/librte_power/rte_power_version.map > index 69ca9af616..3f2f6cd6f6 100644 > --- a/lib/librte_power/rte_power_version.map > +++ b/lib/librte_power/rte_power_version.map > @@ -34,4 +34,8 @@ EXPERIMENTAL { > rte_power_guest_channel_receive_msg; > rte_power_poll_stat_fetch; > rte_power_poll_stat_update; > + # added in 20.11 > + rte_power_pmd_mgmt_queue_enable; > + rte_power_pmd_mgmt_queue_disable; > + > }; > -- > 2.17.1