[ovs-dev] [ovs-dev, v5, 2/3] dpif-netdev: Detailed performance stats for PMDs
Ilya Maximets
i.maximets at samsung.com
Tue Jan 9 08:53:30 UTC 2018
Comments inline.
On 04.01.2018 15:07, Jan Scheurich wrote:
> This patch instruments the dpif-netdev datapath to record detailed
> statistics of what is happening in every iteration of a PMD thread.
>
> The collection of detailed statistics can be controlled by a new
> configuration parameter "other_config:pmd-perf-metrics". By default it
> is disabled. The run-time overhead, when enabled, is in the order of 1%.
>
> The covered metrics per iteration are:
> - cycles
> - packets
> - (rx) batches
> - packets/batch
> - max. vhostuser qlen
> - upcalls
> - cycles spent in upcalls
>
> This raw recorded data is used threefold:
>
> 1. In histograms for each of the following metrics:
> - cycles/iteration (log.)
> - packets/iteration (log.)
> - cycles/packet
> - packets/batch
> - max. vhostuser qlen (log.)
> - upcalls
> - cycles/upcall (log)
> The histograms bins are divided linear or logarithmic.
>
> 2. A cyclic history of the above statistics for 1024 iterations
>
> 3. A cyclic history of the cummulative/average values per millisecond
> wall clock for the last 1024 milliseconds:
> - number of iterations
> - avg. cycles/iteration
> - packets (Kpps)
> - avg. packets/batch
> - avg. max vhost qlen
> - upcalls
> - avg. cycles/upcall
>
> The gathered performance statists can be printed at any time with the
> new CLI command
>
> ovs-appctl dpif-netdev/pmd-perf-show [-nh] [-it iter_len] [-ms ms_len]
> [-pmd core] [dp]
>
> The options are
>
> -nh: Suppress the histograms
> -it iter_len: Display the last iter_len iteration stats
> -ms ms_len: Display the last ms_len millisecond stats
> -pmd core: Display only
>
> The performance statistics are reset with the existing
> dpif-netdev/pmd-stats-clear command.
>
> The output always contains the following global PMD statistics,
> similar to the pmd-stats-show command:
>
> Time: 15:24:55.270
> Measurement duration: 1.008 s
>
> pmd thread numa_id 0 core_id 1:
>
> Cycles: 2419034712 (2.40 GHz)
> Iterations: 572817 (1.76 us/it)
> - idle: 486808 (15.9 % cycles)
> - busy: 86009 (84.1 % cycles)
> Packets: 2399607 (2381 Kpps, 848 cycles/pkt)
> Datapath passes: 3599415 (1.50 passes/pkt)
> - EMC hits: 336472 ( 9.3 %)
> - Megaflow hits: 3262943 (90.7 %, 1.00 subtbl lookups/hit)
> - Upcalls: 0 ( 0.0 %, 0.0 us/upcall)
> - Lost upcalls: 0 ( 0.0 %)
>
> Signed-off-by: Jan Scheurich <jan.scheurich at ericsson.com>
> ---
> lib/dp-packet.h | 2 +
> lib/dpif-netdev-perf.c | 309 ++++++++++++++++++++++++++++++++++++++++++++++++-
> lib/dpif-netdev-perf.h | 173 ++++++++++++++++++++++++++-
> lib/dpif-netdev.c | 158 +++++++++++++++++++++++--
> lib/netdev-dpdk.c | 23 +++-
> lib/netdev-dpdk.h | 14 +++
> ofproto/ofproto-dpif.c | 3 +-
> 7 files changed, 664 insertions(+), 18 deletions(-)
>
> diff --git a/lib/dp-packet.h b/lib/dp-packet.h
> index b4b721c..7950247 100644
> --- a/lib/dp-packet.h
> +++ b/lib/dp-packet.h
> @@ -695,8 +695,10 @@ enum { NETDEV_MAX_BURST = 32 }; /* Maximum number packets in a batch. */
>
> struct dp_packet_batch {
> size_t count;
> + size_t qfill; /* Number of packets in queue when reading rx burst. */
This change looks completely wrog for me. 'qfill' should not be here.
This and all the related stuff in further code turns internatls of netdev-dpdk
inside out and pushes them to the higher level. I don't like this.
Also, currently there are at least 3 patch-sets in OVS mail list targeted to get
some statisics and performance counters.
Can we just use approach similar to "netdev: Custom statistics." ?
(https://mail.openvswitch.org/pipermail/ovs-dev/2018-January/342724.html)
We may collect drops or count high values of qfill using coverage counters or
in some other way.
'qfill', IMHO, should not belong to generic dp_packet_batch structure.
Butches are not for this.
> bool trunc; /* true if the batch needs truncate. */
> struct dp_packet *packets[NETDEV_MAX_BURST];
> +
Not needed empty line.
> };
>
> static inline void
> diff --git a/lib/dpif-netdev-perf.c b/lib/dpif-netdev-perf.c
> index 7d8b7b2..a66a48c 100644
> --- a/lib/dpif-netdev-perf.c
> +++ b/lib/dpif-netdev-perf.c
> @@ -15,6 +15,7 @@
> */
>
> #include <config.h>
> +#include <stdint.h>
>
> #ifdef DPDK_NETDEV
> #include <rte_cycles.h>
> @@ -27,13 +28,307 @@
>
> VLOG_DEFINE_THIS_MODULE(pmd_perf);
>
> +#ifdef DPDK_NETDEV
> +static uint64_t
> +get_tsc_hz(void)
> +{
> + return rte_get_tsc_hz();
> +}
> +#else
> +static uint64_t
> +read_tsc(void)
> +{
> + register uint64_t tsc asm("eax");
> + asm volatile (".byte 15, 49" : : : "eax", "edx");
> + return tsc;
> +}
This breaks non-x86 build:
lib/dpif-netdev-perf.c:58:31: error: unknown register name 'eax' in asm
register uint64_t tsc asm("eax");
^
lib/dpif-netdev-perf.c:59:40: error: unknown register name 'eax' in asm
asm volatile (".byte 15, 49" : : : "eax", "edx");
> +
> +static uint64_t
> +get_tsc_hz(void)
> +{
> + uint64_t tsc_start = read_tsc();
> + xsleep(1);
> + return read_tsc() - tsc_start;
> +}
> +#endif
> +
> +static void
> +histogram_walls_set_lin(struct histogram *hist, uint32_t min, uint32_t max)
> +{
> + int i;
> +
> + ovs_assert(min < max);
> + for (i = 0; i < NUM_BINS-1; i++) {
> + hist->wall[i] = min + (i * (max - min)) / (NUM_BINS - 2);
> + }
> + hist->wall[NUM_BINS-1] = UINT32_MAX;
> +}
> +
> +static void
> +histogram_walls_set_log(struct histogram *hist, uint32_t min, uint32_t max)
> +{
> + int i, start, bins, wall;
> + double log_min, log_max;
> +
> + ovs_assert(min < max);
> + if (min > 0) {
> + log_min = log(min);
> + log_max = log(max);
> + start = 0;
> + bins = NUM_BINS - 1;
> + } else {
> + hist->wall[0] = 0;
> + log_min = log(1);
> + log_max = log(max);
> + start = 1;
> + bins = NUM_BINS - 2;
> + }
> + wall = start;
> + for (i = 0; i < bins; i++) {
> + /* Make sure each wall is monotonically increasing. */
> + wall = MAX(wall, exp(log_min + (i * (log_max - log_min)) / (bins-1)));
> + hist->wall[start + i] = wall++;
> + }
> + if (hist->wall[NUM_BINS-2] < max) {
> + hist->wall[NUM_BINS-2] = max;
> + }
> + hist->wall[NUM_BINS-1] = UINT32_MAX;
> +}
> +
> +uint64_t
> +histogram_samples(const struct histogram *hist)
> +{
> + uint64_t samples = 0;
> +
> + for (int i = 0; i < NUM_BINS; i++) {
> + samples += hist->bin[i];
> + }
> + return samples;
> +}
> +
> +static void
> +histogram_clear(struct histogram *hist)
> +{
> + int i;
> +
> + for (i = 0; i < NUM_BINS; i++) {
> + hist->bin[i] = 0;
> + }
> +}
> +
> +static void
> +history_init(struct history *h)
> +{
> + memset(h, 0, sizeof(*h));
> +}
> +
> void
> pmd_perf_stats_init(struct pmd_perf_stats *s) {
> - memset(s, 0 , sizeof(*s));
> + /* The struct has been zeroed at allocation. */
> + histogram_walls_set_log(&s->cycles, 500, 24000000);
> + histogram_walls_set_log(&s->pkts, 0, 1000);
> + histogram_walls_set_lin(&s->cycles_per_pkt, 100, 30000);
> + histogram_walls_set_lin(&s->pkts_per_batch, 0, 32);
> + histogram_walls_set_lin(&s->upcalls, 0, 30);
> + histogram_walls_set_log(&s->cycles_per_upcall, 1000, 1000000);
> + histogram_walls_set_log(&s->max_vhost_qfill, 0, 512);
> s->start_ms = time_msec();
> }
>
> void
> +pmd_perf_format_overall_stats(struct ds *str, struct pmd_perf_stats *s,
> + double duration)
> +{
> + uint64_t stats[PMD_N_STATS];
> + double us_per_cycle = 1000000.0 / get_tsc_hz();
> +
> + if (duration == 0) {
> + return;
> + }
> +
> + pmd_perf_read_counters(s, stats);
> + uint64_t tot_cycles = stats[PMD_CYCLES_ITER_IDLE] +
> + stats[PMD_CYCLES_ITER_BUSY];
> + uint64_t packets = stats[PMD_STAT_RECV];
> + uint64_t passes = stats[PMD_STAT_RECV] +
> + stats[PMD_STAT_RECIRC];
> + uint64_t upcalls = stats[PMD_STAT_MISS];
> + uint64_t upcall_cycles = stats[PMD_CYCLES_UPCALL];
> + uint64_t tot_iter = histogram_samples(&s->pkts);
> + uint64_t idle_iter = s->pkts.bin[0];
> + uint64_t busy_iter = tot_iter >= idle_iter ? tot_iter - idle_iter : 0;
> +
> + ds_put_format(str,
> + " Cycles: %12"PRIu64" (%.2f GHz)\n"
> + " Iterations: %12"PRIu64" (%.2f us/it)\n"
> + " - idle: %12"PRIu64" (%4.1f %% cycles)\n"
> + " - busy: %12"PRIu64" (%4.1f %% cycles)\n",
> + tot_cycles, (tot_cycles / duration) / 1E9,
> + tot_iter, tot_cycles * us_per_cycle / tot_iter,
> + idle_iter,
> + 100.0 * stats[PMD_CYCLES_ITER_IDLE] / tot_cycles,
> + busy_iter,
> + 100.0 * stats[PMD_CYCLES_ITER_BUSY] / tot_cycles);
> + if (packets > 0) {
> + ds_put_format(str,
> + " Packets: %12"PRIu64" (%.0f Kpps, %.0f cycles/pkt)\n"
> + " Datapath passes: %12"PRIu64" (%.2f passes/pkt)\n"
> + " - EMC hits: %12"PRIu64" (%4.1f %%)\n"
> + " - Megaflow hits: %12"PRIu64" (%4.1f %%, %.2f subtbl lookups/"
> + "hit)\n"
> + " - Upcalls: %12"PRIu64" (%4.1f %%, %.1f us/upcall)\n"
> + " - Lost upcalls: %12"PRIu64" (%4.1f %%)\n"
> + "\n",
> + packets, (packets / duration) / 1000,
> + 1.0 * stats[PMD_CYCLES_ITER_BUSY] / packets,
> + passes, packets ? 1.0 * passes / packets : 0,
> + stats[PMD_STAT_EXACT_HIT],
> + 100.0 * stats[PMD_STAT_EXACT_HIT] / passes,
> + stats[PMD_STAT_MASKED_HIT],
> + 100.0 * stats[PMD_STAT_MASKED_HIT] / passes,
> + stats[PMD_STAT_MASKED_HIT]
> + ? 1.0 * stats[PMD_STAT_MASKED_LOOKUP] / stats[PMD_STAT_MASKED_HIT]
> + : 0,
> + upcalls, 100.0 * upcalls / passes,
> + upcalls ? (upcall_cycles * us_per_cycle) / upcalls : 0,
> + stats[PMD_STAT_LOST],
> + 100.0 * stats[PMD_STAT_LOST] / passes);
> + } else {
> + ds_put_format(str,
> + " Packets: %12"PRIu64"\n"
> + "\n",
> + 0UL);
> + }
> +}
> +
> +void
> +pmd_perf_format_histograms(struct ds *str, struct pmd_perf_stats *s)
> +{
> + int i;
> +
> + ds_put_cstr(str, "Histograms\n");
> + ds_put_format(str,
> + " %-21s %-21s %-21s %-21s %-21s %-21s %-21s\n",
> + "cycles/it", "packets/it", "cycles/pkt", "pkts/batch",
> + "max vhost qlen", "upcalls/it", "cycles/upcall");
> + for (i = 0; i < NUM_BINS-1; i++) {
> + ds_put_format(str,
> + " %-9d %-11"PRIu64" %-9d %-11"PRIu64" %-9d %-11"PRIu64
> + " %-9d %-11"PRIu64" %-9d %-11"PRIu64" %-9d %-11"PRIu64
> + " %-9d %-11"PRIu64"\n",
> + s->cycles.wall[i], s->cycles.bin[i],
> + s->pkts.wall[i],s->pkts.bin[i],
> + s->cycles_per_pkt.wall[i], s->cycles_per_pkt.bin[i],
> + s->pkts_per_batch.wall[i], s->pkts_per_batch.bin[i],
> + s->max_vhost_qfill.wall[i], s->max_vhost_qfill.bin[i],
> + s->upcalls.wall[i], s->upcalls.bin[i],
> + s->cycles_per_upcall.wall[i], s->cycles_per_upcall.bin[i]);
> + }
> + ds_put_format(str,
> + " %-9s %-11"PRIu64" %-9s %-11"PRIu64" %-9s %-11"PRIu64
> + " %-9s %-11"PRIu64" %-9s %-11"PRIu64" %-9s %-11"PRIu64
> + " %-9s %-11"PRIu64"\n",
> + ">", s->cycles.bin[i],
> + ">", s->pkts.bin[i],
> + ">", s->cycles_per_pkt.bin[i],
> + ">", s->pkts_per_batch.bin[i],
> + ">", s->max_vhost_qfill.bin[i],
> + ">", s->upcalls.bin[i],
> + ">", s->cycles_per_upcall.bin[i]);
> + if (s->totals.iterations > 0) {
> + ds_put_cstr(str,
> + "-----------------------------------------------------"
> + "-----------------------------------------------------"
> + "------------------------------------------------\n");
> + ds_put_format(str,
> + " %-21s %-21s %-21s %-21s %-21s %-21s %-21s\n",
> + "cycles/it", "packets/it", "cycles/pkt", "pkts/batch",
> + "vhost qlen", "upcalls/it", "cycles/upcall");
> + ds_put_format(str,
> + " %-21"PRIu64" %-21.5f %-21"PRIu64
> + " %-21.5f %-21.5f %-21.5f %-21"PRIu32"\n",
> + s->totals.cycles / s->totals.iterations,
> + 1.0 * s->totals.pkts / s->totals.iterations,
> + s->totals.pkts
> + ? s->totals.busy_cycles / s->totals.pkts : 0,
> + s->totals.batches
> + ? 1.0 * s->totals.pkts / s->totals.batches : 0,
> + 1.0 * s->totals.max_vhost_qfill / s->totals.iterations,
> + 1.0 * s->totals.upcalls / s->totals.iterations,
> + s->totals.upcalls
> + ? s->totals.upcall_cycles / s->totals.upcalls : 0);
> + }
> +}
> +
> +void
> +pmd_perf_format_iteration_history(struct ds *str, struct pmd_perf_stats *s,
> + int n_iter)
> +{
> + struct iter_stats *is;
> + size_t index;
> + int i;
> +
> + if (n_iter == 0) {
> + return;
> + }
> + ds_put_format(str, " %-17s %-10s %-10s %-10s %-10s "
> + "%-10s %-10s %-10s\n",
> + "tsc", "cycles", "packets", "cycles/pkt", "pkts/batch",
> + "vhost qlen", "upcalls", "cycles/upcall");
> + for (i = 1; i <= n_iter; i++) {
> + index = (s->iterations.idx + HISTORY_LEN - i) % HISTORY_LEN;
> + is = &s->iterations.sample[index];
> + ds_put_format(str,
> + " %-17"PRIu64" %-11"PRIu64" %-11"PRIu32
> + " %-11"PRIu64" %-11"PRIu32" %-11"PRIu32
> + " %-11"PRIu32" %-11"PRIu32"\n",
> + is->timestamp,
> + is->cycles,
> + is->pkts,
> + is->pkts ? is->cycles / is->pkts : 0,
> + is->batches ? is->pkts / is->batches : 0,
> + is->max_vhost_qfill,
> + is->upcalls,
> + is->upcalls ? is->upcall_cycles / is->upcalls : 0);
> + }
> +}
> +
> +void
> +pmd_perf_format_ms_history(struct ds *str, struct pmd_perf_stats *s, int n_ms)
> +{
> + struct iter_stats *is;
> + size_t index;
> + int i;
> +
> + if (n_ms == 0) {
> + return;
> + }
> + ds_put_format(str,
> + " %-12s %-10s %-10s %-10s %-10s"
> + " %-10s %-10s %-10s %-10s\n",
> + "ms", "iterations", "cycles/it", "Kpps", "cycles/pkt",
> + "pkts/batch", "vhost qlen", "upcalls", "cycles/upcall");
> + for (i = 1; i <= n_ms; i++) {
> + index = (s->milliseconds.idx + HISTORY_LEN - i) % HISTORY_LEN;
> + is = &s->milliseconds.sample[index];
> + ds_put_format(str,
> + " %-12"PRIu64" %-11"PRIu32" %-11"PRIu64
> + " %-11"PRIu32" %-11"PRIu64" %-11"PRIu32
> + " %-11"PRIu32" %-11"PRIu32" %-11"PRIu32"\n",
> + is->timestamp,
> + is->iterations,
> + is->iterations ? is->cycles / is->iterations : 0,
> + is->pkts,
> + is->pkts ? is->busy_cycles / is->pkts : 0,
> + is->batches ? is->pkts / is->batches : 0,
> + is->iterations
> + ? is->max_vhost_qfill / is->iterations : 0,
> + is->upcalls,
> + is->upcalls ? is->upcall_cycles / is->upcalls : 0);
> + }
> +}
> +
> +void
> pmd_perf_read_counters(struct pmd_perf_stats *s,
> uint64_t stats[PMD_N_STATS])
> {
> @@ -59,8 +354,20 @@ void
> pmd_perf_stats_clear(struct pmd_perf_stats *s)
> {
> s->start_ms = 0; /* Marks start of clearing. */
> + memset(&s->current, 0 , sizeof(struct iter_stats));
> + memset(&s->totals, 0 , sizeof(struct iter_stats));
> for (int i = 0; i < PMD_N_STATS; i++) {
> atomic_read_relaxed(&s->counters.n[i], &s->counters.zero[i]);
> }
> + histogram_clear(&s->cycles);
> + histogram_clear(&s->pkts);
> + histogram_clear(&s->cycles_per_pkt);
> + histogram_clear(&s->upcalls);
> + histogram_clear(&s->cycles_per_upcall);
> + histogram_clear(&s->pkts_per_batch);
> + histogram_clear(&s->max_vhost_qfill);
> + history_init(&s->iterations);
> + history_init(&s->milliseconds);
> s->start_ms = time_msec(); /* Clearing finished. */
> + s->milliseconds.sample[0].timestamp = s->start_ms;
> }
> diff --git a/lib/dpif-netdev-perf.h b/lib/dpif-netdev-perf.h
> index fa5cf37..3611723 100644
> --- a/lib/dpif-netdev-perf.h
> +++ b/lib/dpif-netdev-perf.h
> @@ -33,6 +33,11 @@
> extern "C" {
> #endif
>
> +#define NUM_BINS 32 /* Number of histogram bins. */
> +#define HISTORY_LEN 1000 /* Length of recorded history
> + (iterations and ms). */
> +#define DEF_HIST_SHOW 20 /* Default number of history samples. */
> +
> enum pmd_stat_type {
> PMD_STAT_EXACT_HIT, /* Packets that had an exact match (emc). */
> PMD_STAT_MASKED_HIT, /* Packets that matched in the flow table. */
> @@ -62,6 +67,28 @@ enum pmd_stat_type {
> PMD_N_STATS
> };
>
> +struct histogram {
> + uint32_t wall[NUM_BINS];
> + uint64_t bin[NUM_BINS];
> +};
> +
> +struct iter_stats {
> + uint64_t timestamp;
> + uint64_t cycles;
> + uint64_t busy_cycles;
> + uint32_t iterations;
> + uint32_t pkts;
> + uint32_t upcalls;
> + uint32_t upcall_cycles;
> + uint32_t batches;
> + uint32_t max_vhost_qfill;
> +};
> +
> +struct history {
> + uint64_t idx;
> + struct iter_stats sample[HISTORY_LEN];
> +};
> +
> struct pmd_counters {
> atomic_uint64_t n[PMD_N_STATS]; /* Indexed by PMD_STAT_*. */
> uint64_t zero[PMD_N_STATS];
> @@ -71,6 +98,17 @@ struct pmd_perf_stats {
> uint64_t start_ms;
> uint64_t last_tsc;
> struct pmd_counters counters;
> + struct iter_stats current;
> + struct iter_stats totals;
> + struct histogram cycles;
> + struct histogram pkts;
> + struct histogram cycles_per_pkt;
> + struct histogram upcalls;
> + struct histogram cycles_per_upcall;
> + struct histogram pkts_per_batch;
> + struct histogram max_vhost_qfill;
> + struct history iterations;
> + struct history milliseconds;
> };
>
> enum pmd_info_type;
> @@ -98,6 +136,63 @@ pmd_perf_update_counter(struct pmd_perf_stats *s,
> atomic_store_relaxed(&s->counters.n[counter], tmp);
> }
>
> +void pmd_perf_format_overall_stats(struct ds *str, struct pmd_perf_stats *s,
> + double duration);
> +void pmd_perf_format_histograms(struct ds *str, struct pmd_perf_stats *s);
> +void pmd_perf_format_iteration_history(struct ds *str,
> + struct pmd_perf_stats *s,
> + int n_iter);
> +void pmd_perf_format_ms_history(struct ds *str, struct pmd_perf_stats *s,
> + int n_ms);
> +
> +void pmd_perf_show(struct unixctl_conn *conn, int argc,
> + const char *argv[],
> + void *aux OVS_UNUSED);
> +static inline void
> +histogram_add_sample(struct histogram *hist, uint32_t val)
> +{
> + /* TODO: Can do better with binary search? */
> + for (int i = 0; i < NUM_BINS-1; i++) {
> + if (val <= hist->wall[i]) {
> + hist->bin[i]++;
> + return;
> + }
> + }
> + hist->bin[NUM_BINS-1]++;
> +}
> +
> +uint64_t histogram_samples(const struct histogram *hist);
> +
> +static inline struct iter_stats *
> +history_current(struct history *h)
> +{
> + return &h->sample[h->idx];
> +}
> +
> +static inline struct iter_stats *
> +history_next(struct history *h)
> +{
> + struct iter_stats *next;
> +
> + h->idx++;
> + if (h->idx == HISTORY_LEN) {
> + h->idx = 0;
> + }
> + next = &h->sample[h->idx];
> + memset(next, 0, sizeof(*next));
> + return next;
> +}
> +
> +static inline struct iter_stats *
> +history_store(struct history *h, struct iter_stats *is)
> +{
> + if (is) {
> + h->sample[h->idx] = *is;
> + }
> + /* Advance the history pointer */
> + return history_next(h);
> +}
> +
> static inline void
> pmd_perf_start_iteration(struct pmd_perf_stats *s, uint64_t now_tsc)
> {
> @@ -105,14 +200,25 @@ pmd_perf_start_iteration(struct pmd_perf_stats *s, uint64_t now_tsc)
> /* Stats not yet fully initialised. */
> return;
> }
> - s->last_tsc = now_tsc;
> + memset(&s->current, 0, sizeof(struct iter_stats));
> + s->current.timestamp = now_tsc;
> }
>
> static inline void
> pmd_perf_end_iteration(struct pmd_perf_stats *s, uint64_t now_tsc,
> - int packets)
> + int packets, bool full_metrics)
> {
> - uint64_t cycles = now_tsc - s->last_tsc;
> + struct iter_stats *cum_ms;
> + uint64_t cycles, cycles_per_pkt = 0;
> +
> + if (OVS_UNLIKELY(s->current.timestamp == 0)) {
> + /* Stats were cleared during the ongoing iteration. */
> + return;
> + }
> +
> + cycles = now_tsc - s->current.timestamp;
> + s->current.cycles = cycles;
> + s->current.pkts = packets;
>
> /* No need for atomic updates as only invoked within PMD thread. */
> if (packets > 0) {
> @@ -120,7 +226,68 @@ pmd_perf_end_iteration(struct pmd_perf_stats *s, uint64_t now_tsc,
> } else {
> s->counters.n[PMD_CYCLES_ITER_IDLE] += cycles;
> }
> + /* Add iteration sample to histograms. */
> + histogram_add_sample(&s->cycles, cycles);
> + histogram_add_sample(&s->pkts, packets);
> +
> + if (!full_metrics) {
> + return;
> + }
> +
> + s->counters.n[PMD_CYCLES_UPCALL] += s->current.upcall_cycles;
> +
> + if (packets > 0) {
> + cycles_per_pkt = cycles / packets;
> + histogram_add_sample(&s->cycles_per_pkt, cycles_per_pkt);
> + }
> + if (s->current.batches > 0) {
> + histogram_add_sample(&s->pkts_per_batch, packets / s->current.batches);
> + }
> + histogram_add_sample(&s->upcalls, s->current.upcalls);
> + if (s->current.upcalls > 0) {
> + histogram_add_sample(&s->cycles_per_upcall,
> + s->current.upcall_cycles / s->current.upcalls);
> + }
> + histogram_add_sample(&s->max_vhost_qfill, s->current.max_vhost_qfill);
> +
> + /* Add iteration samples to millisecond stats. */
> + cum_ms = history_current(&s->milliseconds);
> + cum_ms->iterations++;
> + cum_ms->cycles += cycles;
> + if (packets > 0) {
> + cum_ms->busy_cycles += cycles;
> + }
> + cum_ms->pkts += s->current.pkts;
> + cum_ms->upcalls += s->current.upcalls;
> + cum_ms->upcall_cycles += s->current.upcall_cycles;
> + cum_ms->batches += s->current.batches;
> + cum_ms->max_vhost_qfill += s->current.max_vhost_qfill;
> +
> + /* Store in iteration history. */
> + history_store(&s->iterations, &s->current);
> + if (now_tsc - s->last_tsc > 10000) {
> + /* Check if ms is completed and store in milliseconds history. */
> + uint64_t now = time_msec();
> + if (now != cum_ms->timestamp) {
> + /* Add ms stats to totals. */
> + s->totals.iterations += cum_ms->iterations;
> + s->totals.cycles += cum_ms->cycles;
> + s->totals.busy_cycles += cum_ms->busy_cycles;
> + s->totals.pkts += cum_ms->pkts;
> + s->totals.upcalls += cum_ms->upcalls;
> + s->totals.upcall_cycles += cum_ms->upcall_cycles;
> + s->totals.batches += cum_ms->batches;
> + s->totals.max_vhost_qfill += cum_ms->max_vhost_qfill;
> + cum_ms = history_next(&s->milliseconds);
> + cum_ms->timestamp = now;
> + }
> + s->last_tsc = now_tsc;
> + }
> +}
> +
> +#ifdef __cplusplus
> }
> +#endif
>
> #ifdef __cplusplus
> }
> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
> index 8b9698a..8f64df3 100644
> --- a/lib/dpif-netdev.c
> +++ b/lib/dpif-netdev.c
> @@ -53,6 +53,7 @@
> #include "id-pool.h"
> #include "latch.h"
> #include "netdev.h"
> +#include "netdev-provider.h"
> #include "netdev-vport.h"
> #include "netlink.h"
> #include "odp-execute.h"
> @@ -278,6 +279,8 @@ struct dp_netdev {
>
> /* Probability of EMC insertions is a factor of 'emc_insert_min'.*/
> OVS_ALIGNED_VAR(CACHE_LINE_SIZE) atomic_uint32_t emc_insert_min;
> + /* Enable collection of PMD performance metrics. */
> + ATOMIC(bool) pmd_perf_metrics;
>
> /* Protects access to ofproto-dpif-upcall interface during revalidator
> * thread synchronization. */
> @@ -703,6 +706,7 @@ static inline bool emc_entry_alive(struct emc_entry *ce);
> static void emc_clear_entry(struct emc_entry *ce);
>
> static void dp_netdev_request_reconfigure(struct dp_netdev *dp);
> +static inline bool pmd_perf_metrics_enabled(const struct dp_netdev_pmd_thread *pmd);
>
> static void
> emc_cache_init(struct emc_cache *flow_cache)
> @@ -786,7 +790,8 @@ get_dp_netdev(const struct dpif *dpif)
> enum pmd_info_type {
> PMD_INFO_SHOW_STATS, /* Show how cpu cycles are spent. */
> PMD_INFO_CLEAR_STATS, /* Set the cycles count to 0. */
> - PMD_INFO_SHOW_RXQ /* Show poll-lists of pmd threads. */
> + PMD_INFO_SHOW_RXQ, /* Show poll-lists of pmd threads. */
> + PMD_INFO_PERF_SHOW, /* Show pmd performance details. */
> };
>
> static void
> @@ -873,8 +878,46 @@ pmd_info_show_stats(struct ds *reply,
> ds_put_format(reply,
> "\tavg processing cycles per packet: "
> "%.02f (%"PRIu64"/%"PRIu64")\n",
> - stats[PMD_CYCLES_POLL_BUSY] / (double)total_packets,
> - stats[PMD_CYCLES_POLL_BUSY], total_packets);
> + stats[PMD_CYCLES_ITER_BUSY] / (double)total_packets,
> + stats[PMD_CYCLES_ITER_BUSY], total_packets);
> +}
> +
> +static void
> +pmd_info_show_perf(struct ds *reply,
> + struct dp_netdev_pmd_thread *pmd,
> + struct pmd_perf_params *par)
> +{
> + if (pmd->core_id != NON_PMD_CORE_ID) {
> + char *time_str =
> + xastrftime_msec("%H:%M:%S.###", time_wall_msec(), true);
> + long long now = time_msec();
> + double duration = (now - pmd->perf_stats.start_ms) / 1000.0;
> +
> + ds_put_cstr(reply, "\n");
> + ds_put_format(reply, "Time: %s\n", time_str);
> + ds_put_format(reply, "Measurement duration: %.3f s\n", duration);
> + ds_put_cstr(reply, "\n");
> + format_pmd_thread(reply, pmd);
> + ds_put_cstr(reply, "\n");
> + pmd_perf_format_overall_stats(reply, &pmd->perf_stats, duration);
> + if (pmd_perf_metrics_enabled(pmd)) {
> + if (par->histograms) {
> + ds_put_cstr(reply, "\n");
> + pmd_perf_format_histograms(reply, &pmd->perf_stats);
> + }
> + if (par->iter_hist_len > 0) {
> + ds_put_cstr(reply, "\n");
> + pmd_perf_format_iteration_history(reply, &pmd->perf_stats,
> + par->iter_hist_len);
> + }
> + if (par->ms_hist_len > 0) {
> + ds_put_cstr(reply, "\n");
> + pmd_perf_format_ms_history(reply, &pmd->perf_stats,
> + par->ms_hist_len);
> + }
> + }
> + free(time_str);
> + }
> }
>
> static int
> @@ -1079,6 +1122,8 @@ dpif_netdev_pmd_info(struct unixctl_conn *conn, int argc, const char *argv[],
> pmd_perf_stats_clear(&pmd->perf_stats);
> } else if (type == PMD_INFO_SHOW_STATS) {
> pmd_info_show_stats(&reply, pmd);
> + } else if (type == PMD_INFO_PERF_SHOW) {
> + pmd_info_show_perf(&reply, pmd, (struct pmd_perf_params *)aux);
> }
> }
> free(pmd_list);
> @@ -1088,6 +1133,48 @@ dpif_netdev_pmd_info(struct unixctl_conn *conn, int argc, const char *argv[],
> unixctl_command_reply(conn, ds_cstr(&reply));
> ds_destroy(&reply);
> }
> +
> +static void
> +pmd_perf_show_cmd(struct unixctl_conn *conn, int argc,
> + const char *argv[],
> + void *aux OVS_UNUSED)
> +{
> + struct pmd_perf_params par;
> + long int it_hist = 0, ms_hist = 0;
> + par.histograms = true;
> +
> + while (argc > 1) {
> + if (!strcmp(argv[1], "-nh")) {
> + par.histograms = false;
> + argc -= 1;
> + argv += 1;
> + } else if (!strcmp(argv[1], "-it") && argc > 2) {
> + it_hist = strtol(argv[2], NULL, 10);
> + if (it_hist < 0) {
> + it_hist = 0;
> + } else if (it_hist > HISTORY_LEN) {
> + it_hist = HISTORY_LEN;
> + }
> + argc -= 2;
> + argv += 2;
> + } else if (!strcmp(argv[1], "-ms") && argc > 2) {
> + ms_hist = strtol(argv[2], NULL, 10);
> + if (ms_hist < 0) {
> + ms_hist = 0;
> + } else if (ms_hist > HISTORY_LEN) {
> + ms_hist = HISTORY_LEN;
> + }
> + argc -= 2;
> + argv += 2;
> + } else {
> + break;
> + }
> + }
> + par.iter_hist_len = it_hist;
> + par.ms_hist_len = ms_hist;
> + par.command_type = PMD_INFO_PERF_SHOW;
> + dpif_netdev_pmd_info(conn, argc, argv, &par);
> +}
>
> static int
> dpif_netdev_init(void)
> @@ -1105,6 +1192,12 @@ dpif_netdev_init(void)
> unixctl_command_register("dpif-netdev/pmd-rxq-show", "[-pmd core | dp]",
> 0, 2, dpif_netdev_pmd_info,
> (void *)&poll_aux);
> + unixctl_command_register("dpif-netdev/pmd-perf-show",
> + "[-nh] [-it iter-history-len]"
> + " [-ms ms-history-len]"
> + " [-pmd core | dp]",
> + 0, 7, pmd_perf_show_cmd,
> + NULL);
> unixctl_command_register("dpif-netdev/pmd-rxq-rebalance", "[dp]",
> 0, 1, dpif_netdev_pmd_rebalance,
> NULL);
> @@ -2980,6 +3073,18 @@ dpif_netdev_set_config(struct dpif *dpif, const struct smap *other_config)
> }
> }
>
> + bool perf_enabled = smap_get_bool(other_config, "pmd-perf-metrics", false);
> + bool cur_perf_enabled;
> + atomic_read_relaxed(&dp->pmd_perf_metrics, &cur_perf_enabled);
> + if (perf_enabled != cur_perf_enabled) {
> + atomic_store_relaxed(&dp->pmd_perf_metrics, perf_enabled);
> + if (perf_enabled) {
> + VLOG_INFO("PMD performance metrics collection enabled");
> + } else {
> + VLOG_INFO("PMD performance metrics collection disabled");
> + }
> + }
> +
> return 0;
> }
>
> @@ -3160,6 +3265,14 @@ cycles_count_intermediate(struct dp_netdev_pmd_thread *pmd,
> }
> }
>
> +static inline bool
> +pmd_perf_metrics_enabled(const struct dp_netdev_pmd_thread *pmd)
> +{
> + bool pmd_perf_enabled;
> + atomic_read_relaxed(&pmd->dp->pmd_perf_metrics, &pmd_perf_enabled);
> + return pmd_perf_enabled;
> +}
> +
> static void
> dp_netdev_rxq_set_cycles(struct dp_netdev_rxq *rx,
> enum rxq_cycles_counter_type type,
> @@ -3236,6 +3349,7 @@ dp_netdev_process_rxq_port(struct dp_netdev_pmd_thread *pmd,
> struct netdev_rxq *rx,
> odp_port_t port_no)
> {
> + struct pmd_perf_stats *s = &pmd->perf_stats;
> struct dp_packet_batch batch;
> int error;
> int batch_cnt = 0;
> @@ -3245,8 +3359,25 @@ dp_netdev_process_rxq_port(struct dp_netdev_pmd_thread *pmd,
> if (!error) {
> *recirc_depth_get() = 0;
> pmd_thread_ctx_time_update(pmd);
> -
> batch_cnt = batch.count;
> + if (pmd_perf_metrics_enabled(pmd)) {
> + /* Update batch histogram. */
> + s->current.batches++;
> + histogram_add_sample(&s->pkts_per_batch, batch_cnt);
> + /* Update the maximum Rx queue fill level. */
> + uint32_t qfill = batch.qfill;
> + switch (netdev_dpdk_get_type(netdev_rxq_get_netdev(rx))) {
> + case DPDK_DEV_VHOST:
> + if (qfill > s->current.max_vhost_qfill) {
> + s->current.max_vhost_qfill = qfill;
> + }
> + break;
> + case DPDK_DEV_ETH:
> + default:
> + break;
> + }
I'm sorry, but I'll vote to not accept changes like this. This is contraversal
to all the modular object-oriented architecure of OVS.
In the worst case you may pass something from this layer to be filled by netdev.
But I don't really like such approach too.
> + }
> + /* Process packet batch. */
> dp_netdev_input(pmd, &batch, port_no);
> dp_netdev_pmd_flush_output_packets(pmd);
> } else if (error != EAGAIN && error != EOPNOTSUPP) {
> @@ -4084,7 +4215,9 @@ reload:
> cycles_count_start(pmd);
> for (;;) {
> uint64_t iter_packets = 0;
> +
> pmd_perf_start_iteration(s, pmd->ctx.last_cycles);
> +
> for (i = 0; i < poll_cnt; i++) {
> process_packets =
> dp_netdev_process_rxq_port(pmd, poll_list[i].rxq->rx,
> @@ -4116,7 +4249,9 @@ reload:
> }
> cycles_count_intermediate(pmd, NULL, PMD_CYCLES_OVERHEAD);
> }
> - pmd_perf_end_iteration(s, pmd->ctx.last_cycles, iter_packets);
> +
> + pmd_perf_end_iteration(s, pmd->ctx.last_cycles, iter_packets,
> + pmd_perf_metrics_enabled(pmd));
> }
>
> cycles_count_end(pmd, PMD_CYCLES_OVERHEAD);
> @@ -5012,6 +5147,7 @@ handle_packet_upcall(struct dp_netdev_pmd_thread *pmd,
> struct match match;
> ovs_u128 ufid;
> int error;
> + uint64_t cycles = cycles_counter();
>
> match.tun_md.valid = false;
> miniflow_expand(&key->mf, &match.flow);
> @@ -5065,9 +5201,15 @@ handle_packet_upcall(struct dp_netdev_pmd_thread *pmd,
> ovs_mutex_unlock(&pmd->flow_mutex);
> emc_probabilistic_insert(pmd, key, netdev_flow);
> }
> - /* Only error ENOSPC can reach here. We process the packet but do not
> - * install a datapath flow. Treat as successful. */
> - return 0;
> + if (pmd_perf_metrics_enabled(pmd)) {
> + /* Update upcall stats. */
> + cycles = cycles_counter() - cycles;
> + struct pmd_perf_stats *s = &pmd->perf_stats;
> + s->current.upcalls++;
> + s->current.upcall_cycles += cycles;
> + histogram_add_sample(&s->cycles_per_upcall, cycles);
Hmm. Why this is done manually? Maybe PMD_CYCLES_UPCALL should be used here?
> + }
> + return error;
> }
>
> static inline void
> diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
> index 364f545..d701621 100644
> --- a/lib/netdev-dpdk.c
> +++ b/lib/netdev-dpdk.c
> @@ -36,6 +36,7 @@
> #include <rte_mbuf.h>
> #include <rte_meter.h>
> #include <rte_pci.h>
> +#include <rte_version.h>
> #include <rte_vhost.h>
> #include <rte_version.h>
>
> @@ -188,11 +189,6 @@ enum { DPDK_RING_SIZE = 256 };
> BUILD_ASSERT_DECL(IS_POW2(DPDK_RING_SIZE));
> enum { DRAIN_TSC = 200000ULL };
>
> -enum dpdk_dev_type {
> - DPDK_DEV_ETH = 0,
> - DPDK_DEV_VHOST = 1,
> -};
> -
> /* Quality of Service */
>
> /* An instance of a QoS configuration. Always associated with a particular
> @@ -835,6 +831,13 @@ netdev_dpdk_cast(const struct netdev *netdev)
> return CONTAINER_OF(netdev, struct netdev_dpdk, up);
> }
>
> +enum dpdk_dev_type
> +netdev_dpdk_get_type(const struct netdev *netdev)
> +{
> + struct netdev_dpdk *dev = netdev_dpdk_cast(netdev);
> + return dev->type;
> +}
> +
> static struct netdev *
> netdev_dpdk_alloc(void)
> {
> @@ -1644,6 +1647,14 @@ netdev_dpdk_vhost_rxq_recv(struct netdev_rxq *rxq,
> return EAGAIN;
> }
>
> + batch->qfill = nb_rx;
> +
> + if (OVS_UNLIKELY(nb_rx == NETDEV_MAX_BURST)) {
> + batch->qfill += rte_vhost_rx_queue_count(netdev_dpdk_get_vid(dev),
> + qid * VIRTIO_QNUM
> + + VIRTIO_TXQ);
This looks strange.
Isn't it illogical to spend addtitional time requesting queue count if
we're already late in packet processing?
> + }
> +
> if (policer) {
> dropped = nb_rx;
> nb_rx = ingress_policer_run(policer,
> @@ -1683,6 +1694,8 @@ netdev_dpdk_rxq_recv(struct netdev_rxq *rxq, struct dp_packet_batch *batch)
> return EAGAIN;
> }
>
> + batch->qfill = nb_rx;
> +
> if (policer) {
> dropped = nb_rx;
> nb_rx = ingress_policer_run(policer,
> diff --git a/lib/netdev-dpdk.h b/lib/netdev-dpdk.h
> index b7d02a7..2b357db 100644
> --- a/lib/netdev-dpdk.h
> +++ b/lib/netdev-dpdk.h
> @@ -22,11 +22,18 @@
> #include "openvswitch/compiler.h"
>
> struct dp_packet;
> +struct netdev;
> +
> +enum dpdk_dev_type {
> + DPDK_DEV_ETH = 0,
> + DPDK_DEV_VHOST = 1,
> +};
>
> #ifdef DPDK_NETDEV
>
> void netdev_dpdk_register(void);
> void free_dpdk_buf(struct dp_packet *);
> +enum dpdk_dev_type netdev_dpdk_get_type(const struct netdev *netdev);
>
> #else
>
> @@ -41,6 +48,13 @@ free_dpdk_buf(struct dp_packet *buf OVS_UNUSED)
> /* Nothing */
> }
>
> +static inline enum dpdk_dev_type
> +netdev_dpdk_get_type(const struct netdev *netdev OVS_UNUSED)
> +{
> + /* Nothing to do. Return value zero to make compiler happy. */
> + return DPDK_DEV_ETH;
> +}
> +
> #endif
>
> #endif /* netdev-dpdk.h */
> diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
> index 43b7b89..3845b12 100644
> --- a/ofproto/ofproto-dpif.c
> +++ b/ofproto/ofproto-dpif.c
> @@ -5317,7 +5317,8 @@ dpif_show_backer(const struct dpif_backer *backer, struct ds *ds)
>
> dpif_get_dp_stats(backer->dpif, &dp_stats);
> ds_put_format(ds, "%s: hit:%"PRIu64" missed:%"PRIu64"\n",
> - dpif_name(backer->dpif), dp_stats.n_hit, dp_stats.n_missed);
> + dpif_name(backer->dpif),
> + dp_stats.n_hit + dp_stats.n_mask_hit, dp_stats.n_missed);
>
> shash_init(&ofproto_shash);
> ofprotos = get_ofprotos(&ofproto_shash);
>
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