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dpif-netdev: Change definitions of 'idle' & 'processing' cycles
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Instead of counting all polling cycles as processing cycles, only count
the cycles where packets were received from the polling.

Signed-off-by: Georg Schmuecking <[email protected]>
Signed-off-by: Ciara Loftus <[email protected]>
Co-authored-by: Georg Schmuecking <[email protected]>
Acked-by: Kevin Traynor <[email protected]>
Signed-off-by: Ben Pfaff <[email protected]>
Acked-by: Ian Stokes <[email protected]>
Tested-by: Ian Stokes <[email protected]>
Acked-by: Darrell Ball <[email protected]>
Signed-off-by: Ben Pfaff <[email protected]>
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@cloftus @gg17 @blp
2 people authored and blp committed Jul 6, 2017
1 parent a91c4cf commit a2ac666
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Showing 2 changed files with 48 additions and 15 deletions.
58 changes: 44 additions & 14 deletions lib/dpif-netdev.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -326,8 +326,9 @@ enum dp_stat_type {
};

enum pmd_cycles_counter_type {
PMD_CYCLES_POLLING, /* Cycles spent polling NICs. */
PMD_CYCLES_PROCESSING, /* Cycles spent processing packets */
PMD_CYCLES_IDLE, /* Cycles spent idle or unsuccessful polling */
PMD_CYCLES_PROCESSING, /* Cycles spent successfully polling and
* processing polled packets */
PMD_N_CYCLES
};

Expand Down Expand Up @@ -804,10 +805,10 @@ pmd_info_show_stats(struct ds *reply,
}

ds_put_format(reply,
"\tpolling cycles:%"PRIu64" (%.02f%%)\n"
"\tidle cycles:%"PRIu64" (%.02f%%)\n"
"\tprocessing cycles:%"PRIu64" (%.02f%%)\n",
cycles[PMD_CYCLES_POLLING],
cycles[PMD_CYCLES_POLLING] / (double)total_cycles * 100,
cycles[PMD_CYCLES_IDLE],
cycles[PMD_CYCLES_IDLE] / (double)total_cycles * 100,
cycles[PMD_CYCLES_PROCESSING],
cycles[PMD_CYCLES_PROCESSING] / (double)total_cycles * 100);

Expand Down Expand Up @@ -3079,30 +3080,43 @@ cycles_count_end(struct dp_netdev_pmd_thread *pmd,
non_atomic_ullong_add(&pmd->cycles.n[type], interval);
}

static void
/* Calculate the intermediate cycle result and add to the counter 'type' */
static inline void
cycles_count_intermediate(struct dp_netdev_pmd_thread *pmd,
enum pmd_cycles_counter_type type)
OVS_NO_THREAD_SAFETY_ANALYSIS
{
unsigned long long new_cycles = cycles_counter();
unsigned long long interval = new_cycles - pmd->last_cycles;
pmd->last_cycles = new_cycles;

non_atomic_ullong_add(&pmd->cycles.n[type], interval);
}

static int
dp_netdev_process_rxq_port(struct dp_netdev_pmd_thread *pmd,
struct netdev_rxq *rx,
odp_port_t port_no)
{
struct dp_packet_batch batch;
int error;
int batch_cnt = 0;

dp_packet_batch_init(&batch);
cycles_count_start(pmd);
error = netdev_rxq_recv(rx, &batch);
cycles_count_end(pmd, PMD_CYCLES_POLLING);
if (!error) {
*recirc_depth_get() = 0;

cycles_count_start(pmd);
batch_cnt = batch.count;
dp_netdev_input(pmd, &batch, port_no);
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);

VLOG_ERR_RL(&rl, "error receiving data from %s: %s",
netdev_rxq_get_name(rx), ovs_strerror(error));
}

return batch_cnt;
}

static struct tx_port *
Expand Down Expand Up @@ -3565,21 +3579,29 @@ dpif_netdev_run(struct dpif *dpif)
struct dp_netdev *dp = get_dp_netdev(dpif);
struct dp_netdev_pmd_thread *non_pmd;
uint64_t new_tnl_seq;
int process_packets = 0;

ovs_mutex_lock(&dp->port_mutex);
non_pmd = dp_netdev_get_pmd(dp, NON_PMD_CORE_ID);
if (non_pmd) {
ovs_mutex_lock(&dp->non_pmd_mutex);
cycles_count_start(non_pmd);
HMAP_FOR_EACH (port, node, &dp->ports) {
if (!netdev_is_pmd(port->netdev)) {
int i;

for (i = 0; i < port->n_rxq; i++) {
dp_netdev_process_rxq_port(non_pmd, port->rxqs[i].rx,
port->port_no);
process_packets =
dp_netdev_process_rxq_port(non_pmd,
port->rxqs[i].rx,
port->port_no);
cycles_count_intermediate(non_pmd, process_packets ?
PMD_CYCLES_PROCESSING
: PMD_CYCLES_IDLE);
}
}
}
cycles_count_end(non_pmd, PMD_CYCLES_IDLE);
dpif_netdev_xps_revalidate_pmd(non_pmd, time_msec(), false);
ovs_mutex_unlock(&dp->non_pmd_mutex);

Expand Down Expand Up @@ -3704,6 +3726,7 @@ pmd_thread_main(void *f_)
bool exiting;
int poll_cnt;
int i;
int process_packets = 0;

poll_list = NULL;

Expand All @@ -3730,10 +3753,15 @@ pmd_thread_main(void *f_)
lc = UINT_MAX;
}

cycles_count_start(pmd);
for (;;) {
for (i = 0; i < poll_cnt; i++) {
dp_netdev_process_rxq_port(pmd, poll_list[i].rx,
poll_list[i].port_no);
process_packets =
dp_netdev_process_rxq_port(pmd, poll_list[i].rx,
poll_list[i].port_no);
cycles_count_intermediate(pmd,
process_packets ? PMD_CYCLES_PROCESSING
: PMD_CYCLES_IDLE);
}

if (lc++ > 1024) {
Expand All @@ -3754,6 +3782,8 @@ pmd_thread_main(void *f_)
}
}

cycles_count_end(pmd, PMD_CYCLES_IDLE);

poll_cnt = pmd_load_queues_and_ports(pmd, &poll_list);
exiting = latch_is_set(&pmd->exit_latch);
/* Signal here to make sure the pmd finishes
Expand Down
5 changes: 4 additions & 1 deletion vswitchd/ovs-vswitchd.8.in
View file
Original file line number Diff line number Diff line change
Expand Up @@ -269,7 +269,10 @@ The sum of ``emc hits'', ``masked hits'' and ``miss'' is the number of
packets received by the datapath. Cycles are counted using the TSC or similar
facilities (when available on the platform). To reset these counters use
\fBdpif-netdev/pmd-stats-clear\fR. The duration of one cycle depends on the
measuring infrastructure.
measuring infrastructure. ``idle cycles'' refers to cycles spent polling
devices but not receiving any packets. ``processing cycles'' refers to cycles
spent polling devices and successfully receiving packets, plus the cycles
spent processing said packets.
.IP "\fBdpif-netdev/pmd-stats-clear\fR [\fIdp\fR]"
Resets to zero the per pmd thread performance numbers shown by the
\fBdpif-netdev/pmd-stats-show\fR command. It will NOT reset datapath or
Expand Down

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