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authorDave Barach <dave@barachs.net>2020-06-02 08:57:36 -0400
committerDave Barach <openvpp@barachs.net>2020-06-03 20:17:45 +0000
commitce412fd7d644a21db9f0a170b88084223b7ee0fe (patch)
treed144f98f626494d7811bcf7fedcad2acf2b0b3f7 /docs/gettingstarted
parent1033b4997e4194e5172b7b12ddf638bfdfdaae22 (diff)
docs: improve handoff queue writeup
Type: docs Signed-off-by: Dave Barach <dave@barachs.net> Change-Id: I4d63a0fbbdb3cc00eac9116f122e5b831d059e33
Diffstat (limited to 'docs/gettingstarted')
-rw-r--r--docs/gettingstarted/developers/vlib.md196
1 files changed, 196 insertions, 0 deletions
diff --git a/docs/gettingstarted/developers/vlib.md b/docs/gettingstarted/developers/vlib.md
index 504ee07a7a0..13844ab455a 100644
--- a/docs/gettingstarted/developers/vlib.md
+++ b/docs/gettingstarted/developers/vlib.md
@@ -645,3 +645,199 @@ enqueue node by freeing dropped packets, or by pushing them to
"error-drop." Either of those actions would be a severe error.
* It's perfectly OK to enqueue packets to the current thread.
+
+Handoff Demo Plugin
+-------------------
+
+Check out the sample (plugin) example in
+.../src/examples/handoffdemo. If you want to build the handoff demo plugin:
+
+```
+$ cd .../src/plugins
+$ ln -s ../examples/handoffdemo
+```
+
+This plugin provides a simple example of how to hand off packets
+between threads. We used it to debug packet-tracer handoff tracing
+support.
+
+# Packet generator input script
+
+```
+ packet-generator new {
+ name x
+ limit 5
+ size 128-128
+ interface local0
+ node handoffdemo-1
+ data {
+ incrementing 30
+ }
+ }
+```
+# Start vpp with 2 worker threads
+
+The demo plugin hands packets from worker 1 to worker 2.
+
+# Enable tracing, and start the packet generator
+
+```
+ trace add pg-input 100
+ packet-generator enable
+```
+
+# Sample Run
+
+```
+ DBGvpp# ex /tmp/pg_input_script
+ DBGvpp# pa en
+ DBGvpp# sh err
+ Count Node Reason
+ 5 handoffdemo-1 packets handed off processed
+ 5 handoffdemo-2 completed packets
+ DBGvpp# show run
+ Thread 1 vpp_wk_0 (lcore 0)
+ Time 133.9, average vectors/node 5.00, last 128 main loops 0.00 per node 0.00
+ vector rates in 3.7331e-2, out 0.0000e0, drop 0.0000e0, punt 0.0000e0
+ Name State Calls Vectors Suspends Clocks Vectors/Call
+ handoffdemo-1 active 1 5 0 4.76e3 5.00
+ pg-input disabled 2 5 0 5.58e4 2.50
+ unix-epoll-input polling 22760 0 0 2.14e7 0.00
+ ---------------
+ Thread 2 vpp_wk_1 (lcore 2)
+ Time 133.9, average vectors/node 5.00, last 128 main loops 0.00 per node 0.00
+ vector rates in 0.0000e0, out 0.0000e0, drop 3.7331e-2, punt 0.0000e0
+ Name State Calls Vectors Suspends Clocks Vectors/Call
+ drop active 1 5 0 1.35e4 5.00
+ error-drop active 1 5 0 2.52e4 5.00
+ handoffdemo-2 active 1 5 0 2.56e4 5.00
+ unix-epoll-input polling 22406 0 0 2.18e7 0.00
+```
+
+Enable the packet tracer and run it again...
+
+```
+ DBGvpp# trace add pg-input 100
+ DBGvpp# pa en
+ DBGvpp# sh trace
+ sh trace
+ ------------------- Start of thread 0 vpp_main -------------------
+ No packets in trace buffer
+ ------------------- Start of thread 1 vpp_wk_0 -------------------
+ Packet 1
+
+ 00:06:50:520688: pg-input
+ stream x, 128 bytes, 0 sw_if_index
+ current data 0, length 128, buffer-pool 0, ref-count 1, trace handle 0x1000000
+ 00000000: 000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d0000
+ 00000020: 0000000000000000000000000000000000000000000000000000000000000000
+ 00000040: 0000000000000000000000000000000000000000000000000000000000000000
+ 00000060: 0000000000000000000000000000000000000000000000000000000000000000
+ 00:06:50:520762: handoffdemo-1
+ HANDOFFDEMO: current thread 1
+
+ Packet 2
+
+ 00:06:50:520688: pg-input
+ stream x, 128 bytes, 0 sw_if_index
+ current data 0, length 128, buffer-pool 0, ref-count 1, trace handle 0x1000001
+ 00000000: 000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d0000
+ 00000020: 0000000000000000000000000000000000000000000000000000000000000000
+ 00000040: 0000000000000000000000000000000000000000000000000000000000000000
+ 00000060: 0000000000000000000000000000000000000000000000000000000000000000
+ 00:06:50:520762: handoffdemo-1
+ HANDOFFDEMO: current thread 1
+
+ Packet 3
+
+ 00:06:50:520688: pg-input
+ stream x, 128 bytes, 0 sw_if_index
+ current data 0, length 128, buffer-pool 0, ref-count 1, trace handle 0x1000002
+ 00000000: 000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d0000
+ 00000020: 0000000000000000000000000000000000000000000000000000000000000000
+ 00000040: 0000000000000000000000000000000000000000000000000000000000000000
+ 00000060: 0000000000000000000000000000000000000000000000000000000000000000
+ 00:06:50:520762: handoffdemo-1
+ HANDOFFDEMO: current thread 1
+
+ Packet 4
+
+ 00:06:50:520688: pg-input
+ stream x, 128 bytes, 0 sw_if_index
+ current data 0, length 128, buffer-pool 0, ref-count 1, trace handle 0x1000003
+ 00000000: 000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d0000
+ 00000020: 0000000000000000000000000000000000000000000000000000000000000000
+ 00000040: 0000000000000000000000000000000000000000000000000000000000000000
+ 00000060: 0000000000000000000000000000000000000000000000000000000000000000
+ 00:06:50:520762: handoffdemo-1
+ HANDOFFDEMO: current thread 1
+
+ Packet 5
+
+ 00:06:50:520688: pg-input
+ stream x, 128 bytes, 0 sw_if_index
+ current data 0, length 128, buffer-pool 0, ref-count 1, trace handle 0x1000004
+ 00000000: 000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d0000
+ 00000020: 0000000000000000000000000000000000000000000000000000000000000000
+ 00000040: 0000000000000000000000000000000000000000000000000000000000000000
+ 00000060: 0000000000000000000000000000000000000000000000000000000000000000
+ 00:06:50:520762: handoffdemo-1
+ HANDOFFDEMO: current thread 1
+
+ ------------------- Start of thread 2 vpp_wk_1 -------------------
+ Packet 1
+
+ 00:06:50:520796: handoff_trace
+ HANDED-OFF: from thread 1 trace index 0
+ 00:06:50:520796: handoffdemo-2
+ HANDOFFDEMO: current thread 2
+ 00:06:50:520867: error-drop
+ rx:local0
+ 00:06:50:520914: drop
+ handoffdemo-2: completed packets
+
+ Packet 2
+
+ 00:06:50:520796: handoff_trace
+ HANDED-OFF: from thread 1 trace index 1
+ 00:06:50:520796: handoffdemo-2
+ HANDOFFDEMO: current thread 2
+ 00:06:50:520867: error-drop
+ rx:local0
+ 00:06:50:520914: drop
+ handoffdemo-2: completed packets
+
+ Packet 3
+
+ 00:06:50:520796: handoff_trace
+ HANDED-OFF: from thread 1 trace index 2
+ 00:06:50:520796: handoffdemo-2
+ HANDOFFDEMO: current thread 2
+ 00:06:50:520867: error-drop
+ rx:local0
+ 00:06:50:520914: drop
+ handoffdemo-2: completed packets
+
+ Packet 4
+
+ 00:06:50:520796: handoff_trace
+ HANDED-OFF: from thread 1 trace index 3
+ 00:06:50:520796: handoffdemo-2
+ HANDOFFDEMO: current thread 2
+ 00:06:50:520867: error-drop
+ rx:local0
+ 00:06:50:520914: drop
+ handoffdemo-2: completed packets
+
+ Packet 5
+
+ 00:06:50:520796: handoff_trace
+ HANDED-OFF: from thread 1 trace index 4
+ 00:06:50:520796: handoffdemo-2
+ HANDOFFDEMO: current thread 2
+ 00:06:50:520867: error-drop
+ rx:local0
+ 00:06:50:520914: drop
+ handoffdemo-2: completed packets
+ DBGvpp#
+```