Currently, the API documentation is ambiguous as to what happens when
certain conditions are met. Document the behavior explicitly, as well as
fix some typos and outdated comments.
Fixes: 6a17919b0e2a ("eal: change power intrinsics API")
Signed-off-by: Anatoly Burakov <[email protected]>
---
.../include/generic/rte_power_intrinsics.h | 20 ++++++++++++-------
1 file changed, 13 insertions(+), 7 deletions(-)
diff --git a/lib/librte_eal/include/generic/rte_power_intrinsics.h
b/lib/librte_eal/include/generic/rte_power_intrinsics.h
index 5960c48c80..dddca3d41c 100644
--- a/lib/librte_eal/include/generic/rte_power_intrinsics.h
+++ b/lib/librte_eal/include/generic/rte_power_intrinsics.h
@@ -35,17 +35,20 @@ struct rte_power_monitor_cond {
/**
* @warning
- * @b EXPERIMENTAL: this API may change without prior notice
+ * @b EXPERIMENTAL: this API may change without prior notice.
*
* Monitor specific address for changes. This will cause the CPU to enter an
* architecture-defined optimized power state until either the specified
* memory address is written to, a certain TSC timestamp is reached, or other
* reasons cause the CPU to wake up.
*
- * Additionally, an `expected` 64-bit value and 64-bit mask are provided. If
- * mask is non-zero, the current value pointed to by the `p` pointer will be
- * checked against the expected value, and if they match, the entering of
- * optimized power state may be aborted.
+ * Additionally, an expected value (`pmc->val`), mask (`pmc->mask`), and data
+ * size (`pmc->size`) are provided in the `pmc` power monitoring condition. If
+ * the mask is non-zero, the current value pointed to by the `pmc->addr`
pointer
+ * will be read and compared against the expected value, and if they match, the
+ * entering of optimized power state will be aborted. This is intended to
+ * prevent the CPU from entering optimized power state and waiting on a write
+ * that has already happened by the time this API is called.
*
* @warning It is responsibility of the user to check if this function is
* supported at runtime using `rte_cpu_get_intrinsics_support()` API call.
@@ -67,11 +70,14 @@ int rte_power_monitor(const struct rte_power_monitor_cond
*pmc,
/**
* @warning
- * @b EXPERIMENTAL: this API may change without prior notice
+ * @b EXPERIMENTAL: this API may change without prior notice.
*
* Wake up a specific lcore that is in a power optimized state and is
monitoring
* an address.
*
+ * @note It is safe to call this function if the lcore in question is not
+ * sleeping. The function will have no effect.
+ *
* @note This function will *not* wake up a core that is in a power optimized
* state due to calling `rte_power_pause`.
*
@@ -83,7 +89,7 @@ int rte_power_monitor_wakeup(const unsigned int lcore_id);
/**
* @warning
- * @b EXPERIMENTAL: this API may change without prior notice
+ * @b EXPERIMENTAL: this API may change without prior notice.
*
* Enter an architecture-defined optimized power state until a certain TSC
* timestamp is reached.
--
2.25.1
