In the review process of the original patch 'masked hits' stat
was renamed to 'megaflow hits', but the man page wasn't updated.
Fixes: 6553d06bd179 ("dpif-netdev: Add dpif-netdev/pmd-stats-*
appctl commands.")
Signed-off-by: Ilya Maximets <i.maximets@samsung.com>
Signed-off-by: Ian Stokes <ian.stokes@intel.com>
This patch enhances dpif-netdev-perf to detect iterations with
suspicious statistics according to the following criteria:
- iteration lasts longer than US_THR microseconds (default 250).
This can be used to capture events where a PMD is blocked or
interrupted for such a period of time that there is a risk for
dropped packets on any of its Rx queues.
- max vhost qlen exceeds a threshold Q_THR (default 128). This can
be used to infer virtio queue overruns and dropped packets inside
a VM, which are not visible in OVS otherwise.
Such suspicious iterations can be logged together with their iteration
statistics to be able to correlate them to packet drop or other events
outside OVS.
A new command is introduced to enable/disable logging at run-time and
to adjust the above thresholds for suspicious iterations:
ovs-appctl dpif-netdev/pmd-perf-log-set on | off
[-b before] [-a after] [-e|-ne] [-us usec] [-q qlen]
Turn logging on or off at run-time (on|off).
-b before: The number of iterations before the suspicious iteration to
be logged (default 5).
-a after: The number of iterations after the suspicious iteration to
be logged (default 5).
-e: Extend logging interval if another suspicious iteration is
detected before logging occurs.
-ne: Do not extend logging interval (default).
-q qlen: Suspicious vhost queue fill level threshold. Increase this
to 512 if the Qemu supports 1024 virtio queue length.
(default 128).
-us usec: change the duration threshold for a suspicious iteration
(default 250 us).
Note: Logging of suspicious iterations itself consumes a considerable
amount of processing cycles of a PMD which may be visible in the iteration
history. In the worst case this can lead OVS to detect another
suspicious iteration caused by logging.
If more than 100 iterations around a suspicious iteration have been
logged once, OVS falls back to the safe default values (-b 5/-a 5/-ne)
to avoid that logging itself causes continuos further logging.
Signed-off-by: Jan Scheurich <jan.scheurich@ericsson.com>
Acked-by: Billy O'Mahony <billy.o.mahony@intel.com>
Signed-off-by: Ian Stokes <ian.stokes@intel.com>
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
Open_vSwitch 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 999 iterations
3. A cyclic history of the cummulative/average values per millisecond
wall clock for the last 1000 milliseconds:
- number of iterations
- avg. cycles/iteration
- packets (Kpps)
- avg. packets/batch
- avg. max vhost qlen
- upcalls
- avg. cycles/upcall
The gathered performance metrics 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 specified PMD
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)
Rx 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 %)
Tx packets: 2399607 (2381 Kpps)
Tx batches: 171400 (14.00 pkts/batch)
Signed-off-by: Jan Scheurich <jan.scheurich@ericsson.com>
Acked-by: Billy O'Mahony <billy.o.mahony@intel.com>
Signed-off-by: Ian Stokes <ian.stokes@intel.com>
