From: Jiri Pirko <j...@mellanox.com>
The problem we try to handle is about offloaded forwarded packets
which are not seen by kernel. Let me try to draw it:
port1 port2 (HW stats are counted here)
\ /
\ /
\ /
--(A)---- ASIC --(B)--
|
(C)
|
CPU (SW stats are counted here)
Now we have couple of flows for TX and RX (direction does not matter here):
1) port1->A->ASIC->C->CPU
For this flow, HW and SW stats are equal.
2) port1->A->ASIC->C->CPU->C->ASIC->B->port2
For this flow, HW and SW stats are equal.
3) port1->A->ASIC->B->port2
For this flow, SW stats are 0.
The purpose of this patchset is to provide facility for user to
find out the difference between flows 1+2 and 3. In other words, user
will be able to see the statistics for the slow-path (through kernel).
Also note that HW stats are what someone calls "accumulated" stats.
Every packet counted by SW is also counted by HW. Not the other way around.
As a default the accumulated stats (HW) will be exposed to user
so the userspace apps can react properly.
This patchset add the SW stats (flows 1+2) under offload related stats, so
in the future we can expose other offload related stat in a similar way.
---
v7->v8:
- patch 2/3
- move helping const from uapi to rtnetlink
- cancel driver xstat nesting if it is empty
v6->v7:
- patch 1/3:
- ndo interface changed to get the wanted stats type as an input.
- change commit message.
- patch 2/3:
- create a nesting for offloaded stat and put SW stats under it.
- change the ndo call to indicate which offload stats we wants.
- change commit message.
- patch 3/3:
- change ndo implementation to match the changes in the previous patches.
- change commit message.
v5->v6:
- patch 2/4 was dropped as requested by Roopa
- patch 1/3:
- comment changed to indicate that default stats are combined stats
- commit massage changed
- patch 2/3: (previously 3/4)
- SW stats return nothing if there is no SW stats ndo
v4->v5:
- updated cover letter
- patch3/4:
- using memcpy directly to copy stats as requested by DaveM
v3->v4:
- patch1/4:
- fixed "return ()" pointed out by EricD
- patch2/4:
- fixed if_nlmsg_size as pointed out by EricD
v2->v3:
- patch1/4:
- added dev_have_sw_stats helper
- patch2/4:
- avoided memcpy as requested by DaveM
- patch3/4:
- use new dev_have_sw_stats helper
v1->v2:
- patch3/4:
- fixed NULL initialization
Nogah Frankel (3):
netdevice: Add offload statistics ndo
net: core: Add offload stats to if_stats_msg
mlxsw: spectrum: Implement offload stats ndo and expose HW stats by
default
drivers/net/ethernet/mellanox/mlxsw/spectrum.c | 129 +++++++++++++++++++++++--
drivers/net/ethernet/mellanox/mlxsw/spectrum.h | 5 +
include/linux/netdevice.h | 12 +++
include/uapi/linux/if_link.h | 9 ++
net/core/rtnetlink.c | 97 ++++++++++++++++++-
5 files changed, 241 insertions(+), 11 deletions(-)
--
2.5.5
