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dpif-netdev: Add simple per pmd-thread cycles counters.

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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@vmware.com>
Acked-by: Ethan Jackson <ethan@nicira.com>
This commit is contained in:
Daniele Di Proietto
2015-04-10 19:09:48 +01:00
committed by Ethan Jackson
parent 77e2b03174
commit 55e3ca97d1
1 changed files with 55 additions and 0 deletions
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55
lib/dpif-netdev.c
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@@ -227,6 +227,12 @@ 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_N_CYCLES
};
/* A port in a netdev-based datapath. */
struct dp_netdev_port {
struct cmap_node node; /* Node in dp_netdev's 'ports'. */
@@ -342,6 +348,12 @@ struct dp_netdev_pmd_stats {
atomic_ullong n[DP_N_STATS];
};
/* Contained by struct dp_netdev_pmd_thread's 'cycle' member. */
struct dp_netdev_pmd_cycles {
/* Indexed by PMD_CYCLES_*. */
atomic_ullong 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
@@ -384,6 +396,12 @@ struct dp_netdev_pmd_thread {
/* Statistics. */
struct dp_netdev_pmd_stats stats;
/* Cycles counters */
struct dp_netdev_pmd_cycles cycles;
/* Used to count cicles. See 'cycles_counter_end()' */
unsigned long long last_cycles;
struct latch exit_latch; /* For terminating the pmd thread. */
atomic_uint change_seq; /* For reloading pmd ports. */
pthread_t thread;
@@ -2259,6 +2277,39 @@ dp_netdev_actions_free(struct dp_netdev_actions *actions)
free(actions);
}
static inline unsigned long long
cycles_counter(void)
{
#ifdef DPDK_NETDEV
return rte_get_tsc_cycles();
#else
return 0;
#endif
}
/* Fake mutex to make sure that the calls to cycles_count_* are balanced */
extern struct ovs_mutex cycles_counter_fake_mutex;
/* Start counting cycles. Must be followed by 'cycles_count_end()' */
static inline void
cycles_count_start(struct dp_netdev_pmd_thread *pmd)
OVS_ACQUIRES(&cycles_counter_fake_mutex)
OVS_NO_THREAD_SAFETY_ANALYSIS
{
pmd->last_cycles = cycles_counter();
}
/* Stop counting cycles and add them to the counter 'type' */
static inline void
cycles_count_end(struct dp_netdev_pmd_thread *pmd,
enum pmd_cycles_counter_type type)
OVS_RELEASES(&cycles_counter_fake_mutex)
OVS_NO_THREAD_SAFETY_ANALYSIS
{
unsigned long long interval = cycles_counter() - pmd->last_cycles;
non_atomic_ullong_add(&pmd->cycles.n[type], interval);
}
static void
dp_netdev_process_rxq_port(struct dp_netdev_pmd_thread *pmd,
@@ -2268,7 +2319,9 @@ dp_netdev_process_rxq_port(struct dp_netdev_pmd_thread *pmd,
struct dp_packet *packets[NETDEV_MAX_RX_BATCH];
int error, cnt;
cycles_count_start(pmd);
error = netdev_rxq_recv(rxq, packets, &cnt);
cycles_count_end(pmd, PMD_CYCLES_POLLING);
if (!error) {
int i;
@@ -2278,7 +2331,9 @@ dp_netdev_process_rxq_port(struct dp_netdev_pmd_thread *pmd,
for (i = 0; i < cnt; i++) {
packets[i]->md = PKT_METADATA_INITIALIZER(port->port_no);
}
cycles_count_start(pmd);
dp_netdev_input(pmd, packets, cnt);
cycles_count_end(pmd, PMD_CYCLES_PROCESSING);
} else if (error != EAGAIN && error != EOPNOTSUPP) {
static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);