[ovs-dev] [PATCH v3 7/9] dpif-netdev: Add simple per pmd-thread cycles counters.
Daniele Di Proietto
diproiettod at vmware.com
Fri Mar 27 13:26:07 UTC 2015
The counters use x86 TSC if available (currently only with DPDK). They
will be exposed by subsequents commits
Signed-off-by: Daniele Di Proietto <diproiettod at vmware.com>
---
lib/dpif-netdev.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 70 insertions(+), 3 deletions(-)
diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
index f7978ad..4543c30 100644
--- a/lib/dpif-netdev.c
+++ b/lib/dpif-netdev.c
@@ -228,6 +228,13 @@ enum dp_stat_type {
DP_N_STATS
};
+enum pmd_cycles_counter_type {
+ PMD_CYCLES_POLLING, /* Cycles spent polling NICs. */
+ PMD_CYCLES_PROCESSING, /* Cycles spent processing packets */
+ PMD_CYCLES_OTHER, /* Cycles spent doing other tasks */
+ PMD_N_CYCLES
+};
+
/* A port in a netdev-based datapath. */
struct dp_netdev_port {
struct cmap_node node; /* Node in dp_netdev's 'ports'. */
@@ -346,6 +353,12 @@ struct dp_netdev_pmd_stats {
unsigned long long int n[DP_N_STATS];
};
+/* Contained by struct dp_netdev_pmd_thread's 'cycle' member. */
+struct dp_netdev_pmd_cycles {
+ /* Indexed by PMD_CYCLES_*. */
+ uint64_t n[PMD_N_CYCLES];
+};
+
/* PMD: Poll modes drivers. PMD accesses devices via polling to eliminate
* the performance overhead of interrupt processing. Therefore netdev can
* not implement rx-wait for these devices. dpif-netdev needs to poll
@@ -387,10 +400,15 @@ struct dp_netdev_pmd_thread {
/* Statistics. */
struct dp_netdev_pmd_stats stats;
- /* Used to protect 'stats'. Only guarantees consistency of single stats
- * members, not of the structure as a whole */
+ /* Cycles counters */
+ struct dp_netdev_pmd_cycles cycles;
+ /* Used to protect 'stats' and 'cycles'. Only guarantees consistency of
+ * single members, not of the structure as a whole */
struct u64_stats_sync stats_lock;
+ /* Used to count cicles. See 'pmd_cycles_counter_diff()' */
+ uint64_t last_cycles;
+
struct latch exit_latch; /* For terminating the pmd thread. */
atomic_uint change_seq; /* For reloading pmd ports. */
pthread_t thread;
@@ -400,6 +418,10 @@ struct dp_netdev_pmd_thread {
int numa_id; /* numa node id of this pmd thread. */
};
+static inline uint64_t pmd_cycles_counter_diff(struct dp_netdev_pmd_thread *);
+static inline void pmd_count_previous_cycles(struct dp_netdev_pmd_thread *,
+ enum pmd_cycles_counter_type);
+
#define PMD_INITIAL_SEQ 1
/* Interface to netdev-based datapath. */
@@ -2089,6 +2111,7 @@ dpif_netdev_execute(struct dpif *dpif, struct dpif_execute *execute)
if (pmd->core_id == NON_PMD_CORE_ID) {
ovs_mutex_lock(&dp->non_pmd_mutex);
ovs_mutex_lock(&dp->port_mutex);
+ pmd_cycles_counter_diff(pmd);
}
pp = execute->packet;
@@ -2098,6 +2121,7 @@ dpif_netdev_execute(struct dpif *dpif, struct dpif_execute *execute)
dp_netdev_pmd_unref(pmd);
ovs_mutex_unlock(&dp->port_mutex);
ovs_mutex_unlock(&dp->non_pmd_mutex);
+ pmd_count_previous_cycles(pmd, PMD_CYCLES_PROCESSING);
}
return 0;
@@ -2240,6 +2264,36 @@ dp_netdev_actions_free(struct dp_netdev_actions *actions)
}
+/* This function returns the length of the interval since the last call
+ * to the function itself (with the same 'pmd' argument) */
+static inline uint64_t
+pmd_cycles_counter_diff(struct dp_netdev_pmd_thread *pmd)
+{
+ uint64_t old_cycles = pmd->last_cycles,
+#ifdef DPDK_NETDEV
+ new_cycles = rte_get_tsc_cycles();
+#else
+ new_cycles = 0;
+#endif
+
+ pmd->last_cycles = new_cycles;
+
+ return new_cycles - old_cycles;
+}
+
+/* Updates the pmd cycles counter, considering the past cycles spent
+ * for the reason specified in 'type' */
+static inline void
+pmd_count_previous_cycles(struct dp_netdev_pmd_thread *pmd,
+ enum pmd_cycles_counter_type type)
+{
+ uint32_t c;
+
+ c = u64_stats_write_begin(&pmd->stats_lock);
+ pmd->cycles.n[type] += pmd_cycles_counter_diff(pmd);
+ u64_stats_write_end(&pmd->stats_lock, c);
+}
+
static void
dp_netdev_process_rxq_port(struct dp_netdev_pmd_thread *pmd,
struct dp_netdev_port *port,
@@ -2252,6 +2306,8 @@ dp_netdev_process_rxq_port(struct dp_netdev_pmd_thread *pmd,
if (!error) {
int i;
+ pmd_count_previous_cycles(pmd, PMD_CYCLES_POLLING);
+
*recirc_depth_get() = 0;
/* XXX: initialize md in netdev implementation. */
@@ -2259,6 +2315,7 @@ dp_netdev_process_rxq_port(struct dp_netdev_pmd_thread *pmd,
packets[i]->md = PKT_METADATA_INITIALIZER(port->port_no);
}
dp_netdev_input(pmd, packets, cnt);
+ pmd_count_previous_cycles(pmd, PMD_CYCLES_PROCESSING);
} else if (error != EAGAIN && error != EOPNOTSUPP) {
static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
@@ -2278,6 +2335,7 @@ dpif_netdev_run(struct dpif *dpif)
uint64_t new_tnl_seq;
ovs_mutex_lock(&dp->non_pmd_mutex);
+ pmd_count_previous_cycles(non_pmd, PMD_CYCLES_OTHER);
CMAP_FOR_EACH (port, node, &dp->ports) {
if (!netdev_is_pmd(port->netdev)) {
int i;
@@ -2388,6 +2446,10 @@ pmd_thread_main(void *f_)
/* Stores the pmd thread's 'pmd' to 'per_pmd_key'. */
ovsthread_setspecific(pmd->dp->per_pmd_key, pmd);
pmd_thread_setaffinity_cpu(pmd->core_id);
+
+ /* Initialize the cycles counter */
+ pmd_cycles_counter_diff(pmd);
+
reload:
emc_cache_init(&pmd->flow_cache);
poll_cnt = pmd_load_queues(pmd, &poll_list, poll_cnt);
@@ -2396,6 +2458,7 @@ reload:
* reloading the updated configuration. */
dp_netdev_pmd_reload_done(pmd);
+ pmd_count_previous_cycles(pmd, PMD_CYCLES_OTHER);
for (;;) {
int i;
@@ -2406,6 +2469,8 @@ reload:
if (lc++ > 1024) {
unsigned int seq;
+ pmd_count_previous_cycles(pmd, PMD_CYCLES_POLLING);
+
lc = 0;
emc_cache_slow_sweep(&pmd->flow_cache);
@@ -2416,6 +2481,7 @@ reload:
port_seq = seq;
break;
}
+
}
}
@@ -2556,10 +2622,11 @@ dp_netdev_configure_pmd(struct dp_netdev_pmd_thread *pmd, struct dp_netdev *dp,
ovs_mutex_init(&pmd->flow_mutex);
dpcls_init(&pmd->cls);
cmap_init(&pmd->flow_table);
- /* init the 'flow_cache' since there is no
+ /* init the 'flow_cache' and cycles counter since there is no
* actual thread created for NON_PMD_CORE_ID. */
if (core_id == NON_PMD_CORE_ID) {
emc_cache_init(&pmd->flow_cache);
+ pmd_cycles_counter_diff(pmd);
}
cmap_insert(&dp->poll_threads, CONST_CAST(struct cmap_node *, &pmd->node),
hash_int(core_id, 0));
--
2.1.4
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