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.
---
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 (4):
netdevice: add SW statistics ndo
rtnetlink: add HW/SW stats distinction in rtnl_fill_stats
net: core: add SW stats to if_stats_msg
mlxsw: spectrum: Implement SW stats ndo and expose HW stats by default
drivers/net/ethernet/mellanox/mlxsw/spectrum.c | 110 +++++++++++++++++++++++--
drivers/net/ethernet/mellanox/mlxsw/spectrum.h | 5 ++
include/linux/netdevice.h | 13 +++
include/uapi/linux/if_link.h | 2 +
net/core/dev.c | 31 +++++++
net/core/rtnetlink.c | 49 +++++++++--
6 files changed, 195 insertions(+), 15 deletions(-)
--
2.5.5
