mwaitx allows epyc processors to enter a implementation dependent
power/performance optimized state (C1 state) for a specific period
or until a store to the monitored address range.
Signed-off-by: Sivaprasad Tummala <sivaprasad.tumm...@amd.com>
---
lib/eal/x86/rte_power_intrinsics.c | 83 ++++++++++++++++++++++++++++--
lib/power/rte_power_pmd_mgmt.c | 3 +-
2 files changed, 82 insertions(+), 4 deletions(-)
diff --git a/lib/eal/x86/rte_power_intrinsics.c
b/lib/eal/x86/rte_power_intrinsics.c
index f749da9b85..d688066b3a 100644
--- a/lib/eal/x86/rte_power_intrinsics.c
+++ b/lib/eal/x86/rte_power_intrinsics.c
@@ -30,6 +30,7 @@ __umwait_wakeup(volatile void *addr)
static bool wait_supported;
static bool wait_multi_supported;
+static bool amd_mwaitx_supported;
static inline uint64_t
__get_umwait_val(const volatile void *p, const uint8_t sz)
@@ -65,6 +66,76 @@ __check_val_size(const uint8_t sz)
}
}
+/**
+ * This function uses MONITORX/MWAITX instructions and will enter C1 state.
+ * For more information about usage of these instructions, please refer to
+ * AMD64 Architecture Programmer’s Manual.
+ */
+static inline int
+amd_power_monitorx(const struct rte_power_monitor_cond *pmc,
+ const uint64_t tsc_timestamp)
+{
+ const unsigned int lcore_id = rte_lcore_id();
+ struct power_wait_status *s;
+ uint64_t cur_value;
+
+ RTE_SET_USED(tsc_timestamp);
+
+ /* prevent non-EAL thread from using this API */
+ if (lcore_id >= RTE_MAX_LCORE)
+ return -EINVAL;
+
+ if (pmc == NULL)
+ return -EINVAL;
+
+ if (__check_val_size(pmc->size) < 0)
+ return -EINVAL;
+
+ if (pmc->fn == NULL)
+ return -EINVAL;
+
+ s = &wait_status[lcore_id];
+
+ /* update sleep address */
+ rte_spinlock_lock(&s->lock);
+ s->monitor_addr = pmc->addr;
+
+ /*
+ * we're using raw byte codes for now as only the newest compiler
+ * versions support this instruction natively.
+ */
+ /* set address for MONITORX */
+ asm volatile(".byte 0x0f, 0x01, 0xfa;"
+ :
+ : "a"(pmc->addr),
+ "c"(0), /* no extensions */
+ "d"(0)); /* no hints */
+
+ /* now that we've put this address into monitor, we can unlock */
+ rte_spinlock_unlock(&s->lock);
+
+ cur_value = __get_umwait_val(pmc->addr, pmc->size);
+
+ /* check if callback indicates we should abort */
+ if (pmc->fn(cur_value, pmc->opaque) != 0)
+ goto end;
+
+ /* execute MWAITX */
+ asm volatile(".byte 0x0f, 0x01, 0xfb;"
+ : /* ignore rflags */
+ : "a"(0), /* enter C1 */
+ "c"(0), /* no time-out */
+ "b"(0));
+
+end:
+ /* erase sleep address */
+ rte_spinlock_lock(&s->lock);
+ s->monitor_addr = NULL;
+ rte_spinlock_unlock(&s->lock);
+
+ return 0;
+}
+
/**
* This function uses UMONITOR/UMWAIT instructions and will enter C0.2 state.
* For more information about usage of these instructions, please refer to
@@ -81,8 +152,12 @@ rte_power_monitor(const struct rte_power_monitor_cond *pmc,
uint64_t cur_value;
/* prevent user from running this instruction if it's not supported */
- if (!wait_supported)
- return -ENOTSUP;
+ if (!wait_supported) {
+ if (amd_mwaitx_supported)
+ return amd_power_monitorx(pmc, tsc_timestamp);
+ else
+ return -ENOTSUP;
+ }
/* prevent non-EAL thread from using this API */
if (lcore_id >= RTE_MAX_LCORE)
@@ -170,6 +245,8 @@ RTE_INIT(rte_power_intrinsics_init) {
wait_supported = 1;
if (i.power_monitor_multi)
wait_multi_supported = 1;
+ if (i.amd_power_monitorx)
+ amd_mwaitx_supported = 1;
}
int
@@ -178,7 +255,7 @@ rte_power_monitor_wakeup(const unsigned int lcore_id)
struct power_wait_status *s;
/* prevent user from running this instruction if it's not supported */
- if (!wait_supported)
+ if (!wait_supported && !amd_mwaitx_supported)
return -ENOTSUP;
/* prevent buffer overrun */
diff --git a/lib/power/rte_power_pmd_mgmt.c b/lib/power/rte_power_pmd_mgmt.c
index ca1840387c..048a41dc29 100644
--- a/lib/power/rte_power_pmd_mgmt.c
+++ b/lib/power/rte_power_pmd_mgmt.c
@@ -447,7 +447,8 @@ check_monitor(struct pmd_core_cfg *cfg, const union queue
*qdata)
bool multimonitor_supported;
/* check if rte_power_monitor is supported */
- if (!global_data.intrinsics_support.power_monitor) {
+ if ((!global_data.intrinsics_support.power_monitor) &&
+ (!global_data.intrinsics_support.amd_power_monitorx)) {
RTE_LOG(DEBUG, POWER, "Monitoring intrinsics are not
supported\n");
return -ENOTSUP;
}
--
2.34.1
