[PATCH V2 0/3] pktgen: Add IMIX mode

[Nicholas Richardson]

From: Nick Richardson <richardsonnick@xxxxxxxxxx>

Adds internet mix (IMIX) mode to pktgen. Internet mix is
included in many user-space network perf testing tools. It allows
for the user to specify a distribution of discrete packet sizes to be
generated. This type of test is common among vendors when perf testing 
their devices.
[RFC link: https://datatracker.ietf.org/doc/html/rfc2544#section-9.1]

This allows users to get a
more complete picture of how their device will perform in the
real-world.

This feature adds a command that allows users to specify an imix
distribution in the following format:
  imix_weights size_1,weight_1 size_2,weight_2 ... size_n,weight_n

The distribution of packets with size_i will be 
(weight_i / total_weights) where
total_weights = weight_1 + weight_2 + ... + weight_n

For example:
  imix_weights 40,7 576,4 1500,1

The pkt_size "40" will account for 7 / (7 + 4 + 1) = ~58% of the total
packets sent.

This patch was tested with the following:
1. imix_weights = 40,7 576,4 1500,1
2. imix_weights = 0,7 576,4 1500,1
  - Packet size of 0 is resized to the minimum, 42
3. imix_weights = 40,7 576,4 1500,1 count = 0
  - Zero count.
  - Runs until user stops pktgen.
Invalid Configurations
1. clone_skb = 200 imix_weights = 40,7 576,4 1500,1
    - Returns error code -524 (-ENOTSUPP) when setting imix_weights
2. len(imix_weights) > MAX_IMIX_ENTRIES
    - Returns -7 (-E2BIG)

This patch is split into three parts, each provide different aspects of
required functionality:
  1. Parse internet mix input.
  2. Add IMIX Distribution representation.
  3. Process and output IMIX results.

Changes in v2:
* Remove __ prefix outside of uAPI.
* Use seq_puts instead of seq_printf where necessary.
* Reorder variable declaration.
* Return -EINVAL instead of -ENOTSUPP when using IMIX with clone_skb > 0 

Nick Richardson (3):
  pktgen: Parse internet mix (imix) input
  pktgen: Add imix distribution bins
  pktgen: Add output for imix results

 net/core/pktgen.c | 163 +++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 162 insertions(+), 1 deletion(-)

-- 
2.32.0.605.g8dce9f2422-goog