[PATCH 3.4 08/65] pktgen: document ability to add same device to several threads

[lizf@kernel.org]

From: Jesper Dangaard Brouer <brouer@redhat.com>

3.4.110-rc1 review patch.  If anyone has any objections, please let me know.

------------------


commit 2a1ddf27e8189e1d68336c55dd2f305b224ae8f1 upstream.

The pktgen.txt documentation still claimed that adding same device to
multiple threads were not supported, but it have been since 2008 via
commit e6fce5b916cd7 ("pktgen: multiqueue etc.").

Document this and describe the naming scheme dev@X, as the procfile name
still need to be unique.

Fixes: e6fce5b916cd7 ("pktgen: multiqueue etc.")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Zefan Li <lizefan@huawei.com>
---
 Documentation/networking/pktgen.txt | 77 +++++++++++++++++++++++--------------
 1 file changed, 49 insertions(+), 28 deletions(-)

diff --git a/Documentation/networking/pktgen.txt b/Documentation/networking/pktgen.txt
index 75e4fd7..a03239c 100644
--- a/Documentation/networking/pktgen.txt
+++ b/Documentation/networking/pktgen.txt
@@ -24,17 +24,33 @@ For monitoring and control pktgen creates:
         /proc/net/pktgen/ethX
 
 
-Viewing threads
-===============
-/proc/net/pktgen/kpktgend_0 
-Name: kpktgend_0  max_before_softirq: 10000
-Running: 
-Stopped: eth1 
-Result: OK: max_before_softirq=10000
+Kernel threads
+==============
+Pktgen creates a thread for each CPU with affinity to that CPU.
+Which is controlled through procfile /proc/net/pktgen/kpktgend_X.
+
+Example: /proc/net/pktgen/kpktgend_0
+
+ Running:
+ Stopped: eth4@0
+ Result: OK: add_device=eth4@0
+
+Most important are the devices assigned to the thread.
 
-Most important the devices assigned to thread. Note! A device can only belong 
-to one thread.
+The two basic thread commands are:
+ * add_device DEVICE@NAME -- adds a single device
+ * rem_device_all         -- remove all associated devices
 
+When adding a device to a thread, a corrosponding procfile is created
+which is used for configuring this device. Thus, device names need to
+be unique.
+
+To support adding the same device to multiple threads, which is useful
+with multi queue NICs, a the device naming scheme is extended with "@":
+ device@something
+
+The part after "@" can be anything, but it is custom to use the thread
+number.
 
 Viewing devices
 ===============
@@ -42,29 +58,32 @@ Viewing devices
 Parm section holds configured info. Current hold running stats. 
 Result is printed after run or after interruption. Example:
 
-/proc/net/pktgen/eth1       
+/proc/net/pktgen/eth4@0
 
-Params: count 10000000  min_pkt_size: 60  max_pkt_size: 60
-     frags: 0  delay: 0  clone_skb: 1000000  ifname: eth1
+ Params: count 100000  min_pkt_size: 60  max_pkt_size: 60
+     frags: 0  delay: 0  clone_skb: 64  ifname: eth4@0
      flows: 0 flowlen: 0
-     dst_min: 10.10.11.2  dst_max: 
-     src_min:   src_max: 
-     src_mac: 00:00:00:00:00:00  dst_mac: 00:04:23:AC:FD:82
-     udp_src_min: 9  udp_src_max: 9  udp_dst_min: 9  udp_dst_max: 9
-     src_mac_count: 0  dst_mac_count: 0 
-     Flags: 
-Current:
-     pkts-sofar: 10000000  errors: 39664
-     started: 1103053986245187us  stopped: 1103053999346329us idle: 880401us
-     seq_num: 10000011  cur_dst_mac_offset: 0  cur_src_mac_offset: 0
-     cur_saddr: 0x10a0a0a  cur_daddr: 0x20b0a0a
-     cur_udp_dst: 9  cur_udp_src: 9
+     queue_map_min: 0  queue_map_max: 0
+     dst_min: 192.168.81.2  dst_max:
+     src_min:   src_max:
+     src_mac: 90:e2:ba:0a:56:b4 dst_mac: 00:1b:21:3c:9d:f8
+     udp_src_min: 9  udp_src_max: 109  udp_dst_min: 9  udp_dst_max: 9
+     src_mac_count: 0  dst_mac_count: 0
+     Flags: UDPSRC_RND  NO_TIMESTAMP  QUEUE_MAP_CPU
+ Current:
+     pkts-sofar: 100000  errors: 0
+     started: 623913381008us  stopped: 623913396439us idle: 25us
+     seq_num: 100001  cur_dst_mac_offset: 0  cur_src_mac_offset: 0
+     cur_saddr: 192.168.8.3  cur_daddr: 192.168.81.2
+     cur_udp_dst: 9  cur_udp_src: 42
+     cur_queue_map: 
      flows: 0
-Result: OK: 13101142(c12220741+d880401) usec, 10000000 (60byte,0frags)
-  763292pps 390Mb/sec (390805504bps) errors: 39664
+ Result: OK: 15430(c15405d25) usec, 100000 (60byte,0frags)
+  6480562pps 3110Mb/sec (3110669760bps) errors: 0
 
-Configuring threads and devices
-================================
+
+Configuring devices
+===================
 This is done via the /proc interface easiest done via pgset in the scripts
 
 Examples:
@@ -177,6 +196,8 @@ Note when adding devices to a specific CPU there good idea to also assign
 /proc/irq/XX/smp_affinity so the TX-interrupts gets bound to the same CPU.
 as this reduces cache bouncing when freeing skb's.
 
+Plus using the device flag QUEUE_MAP_CPU, which maps the SKBs TX queue
+to the running threads CPU (directly from smp_processor_id()).
 
 Current commands and configuration options
 ==========================================
-- 
1.9.1