[1/2] eal: add API that sleeps while waiting for threads
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Commit Message
It is common that sample applications call rte_eal_wait_lcore() while
waiting for worker threads to be terminated.
Mostly master lcore keeps waiting in this function.
The waiting app for termination is not a time critical task, app can
prefer a sleep version of the waiting to consume less cycles.
A sleeping version of the API, rte_eal_wait_lcore_sleep(), has been
added which gets sleeping interval as parameter.
Sample applications will be updated later to use this API.
Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
---
lib/librte_eal/common/eal_common_launch.c | 22 ++++++++++++++++++
lib/librte_eal/common/include/rte_launch.h | 27 ++++++++++++++++++++++
lib/librte_eal/rte_eal_version.map | 1 +
3 files changed, 50 insertions(+)
Comments
On Thu, 11 Oct 2018 20:57:52 +0100
Ferruh Yigit <ferruh.yigit@intel.com> wrote:
> +/*
> + * Wait until a lcore finished its job by sleeping.
> + * Sleep time will be times of 'usec'
> + */
> +int
> +rte_eal_wait_lcore_sleep(unsigned slave_id, size_t usec)
> +{
> + if (lcore_config[slave_id].state == WAIT)
> + return 0;
> +
> + while (lcore_config[slave_id].state != WAIT &&
> + lcore_config[slave_id].state != FINISHED)
> + usleep(usec);
> +
> + rte_rmb();
> +
> + /* we are in finished state, go to wait state */
> + lcore_config[slave_id].state = WAIT;
> + return lcore_config[slave_id].ret;
> +}
> +
Since lcore threads are really pthreads you could avoid doing polling by
using a pthread condition (ie. pthread_cond_wait and/or pthread_cond_timedwait)
@@ -5,6 +5,7 @@
#include <errno.h>
#include <stdint.h>
#include <stdio.h>
+#include <unistd.h>
#include <sys/queue.h>
#include <rte_launch.h>
@@ -35,6 +36,27 @@ rte_eal_wait_lcore(unsigned slave_id)
return lcore_config[slave_id].ret;
}
+/*
+ * Wait until a lcore finished its job by sleeping.
+ * Sleep time will be times of 'usec'
+ */
+int
+rte_eal_wait_lcore_sleep(unsigned slave_id, size_t usec)
+{
+ if (lcore_config[slave_id].state == WAIT)
+ return 0;
+
+ while (lcore_config[slave_id].state != WAIT &&
+ lcore_config[slave_id].state != FINISHED)
+ usleep(usec);
+
+ rte_rmb();
+
+ /* we are in finished state, go to wait state */
+ lcore_config[slave_id].state = WAIT;
+ return lcore_config[slave_id].ret;
+}
+
/*
* Check that every SLAVE lcores are in WAIT state, then call
* rte_eal_remote_launch() for all of them. If call_master is true
@@ -11,6 +11,8 @@
* Launch tasks on other lcores
*/
+#include <rte_compat.h>
+
#ifdef __cplusplus
extern "C" {
#endif
@@ -129,6 +131,31 @@ enum rte_lcore_state_t rte_eal_get_lcore_state(unsigned slave_id);
*/
int rte_eal_wait_lcore(unsigned slave_id);
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Wait until an lcore finishes its job.
+ *
+ * To be executed on the MASTER lcore only.
+ *
+ * Same as rte_eal_wait_lcore() but sleeps instead of busy wait.
+ *
+ * @param slave_id
+ * The identifier of the lcore.
+ * @param usec
+ * The sleep interval in microseconds
+ * @return
+ * - 0: If the lcore identified by the slave_id is in a WAIT state.
+ * - The value that was returned by the previous remote launch
+ * function call if the lcore identified by the slave_id was in a
+ * FINISHED or RUNNING state. In this case, it changes the state
+ * of the lcore to WAIT.
+ */
+__rte_experimental int
+rte_eal_wait_lcore_sleep(unsigned slave_id, size_t usec);
+
/**
* Wait until all lcores finish their jobs.
*
@@ -292,6 +292,7 @@ EXPERIMENTAL {
rte_devargs_remove;
rte_devargs_type_count;
rte_eal_cleanup;
+ rte_eal_wait_lcore_sleep;
rte_fbarray_attach;
rte_fbarray_destroy;
rte_fbarray_detach;