On 3/26/24 03:30, Chris Mi via dev wrote:
This patch set adds offload support for sFlow.
Psample is a genetlink channel for packet sampling. TC action act_sample
uses psample to send sampled packets to userspace.
When offloading sample action to TC, userspace creates a unique ID to
map sFlow action and tunnel info and passes this ID to kernel instead
of the sFlow info. psample will send this ID and sampled packet to
userspace. Using the ID, userspace can recover the sFlow info and send
sampled packet to the right sFlow monitoring host.
Hi Chris,
I have been also looking at psample. Please see [1]. The goal is to use psample
to make the sample action send packets directly to external consumers.
However, it collides with the design strategy taken in this series. In
particular with the use of the group_id. Psample group_ids seem to be used to
distinguish between different sources of samples. However, with this series OVS
will use up the entire 32-bit space.
In order to support both usecases (and other users of psample), I have proposed
adding a variable length user-defined cookie to the psample metadata and to
act_sample so OVS could use the cookie instead of the group_id to store the
internal key to the full sFlow data.
I would really like your take on this alternative.
I would be fine doing the work to adapt the sFlow offloading infrastructure to
the new psample + cookie strategy (if/when merged upstream). However, I'm
concerned that this would be breaking backwards compatibility as we would no
longer support kernels that do not have the cookie support.
What do you think?
[1]
https://patchwork.kernel.org/project/netdevbpf/cover/20240408125753.470419-1-amore...@redhat.com/
Thanks.
Adrián
v2-v1:
- Fix robot errors.
v3-v2:
- Remove Gerrit Change-Id.
- Add patch #9 to fix older kernels build issue.
- Add travis test result.
v4-v3:
- Fix offload issue when sampling rate is 1.
v5-v4:
- Move polling thread from ofproto to netdev-offload-tc.
v6-v5:
- Rebase.
- Add GitHub Actions test result.
v7-v6:
- Remove Gerrit Change-Id.
- Fix "ERROR: Inappropriate spacing around cast"
v8-v7
- Address Eelco Chaudron's comment for patch #11.
v9-v8
- Remove sflow_len from struct dpif_sflow_attr.
- Log a debug message for other userspace actions.
v10-v9
- Address Eelco Chaudron's comments on v9.
v11-v10
- Fix a bracing error.
v12-v11
- Add duplicate sample group id check.
v13-v12
- Remove the psample poll thread from netdev-offload-tc and reuse
ofproto handler thread according to Ilya's new desgin.
- Add dpif-offload-provider layer according to Eli's suggestion.
v14-v13
- Fix a robot error.
v15-v14
- Address Eelco Chaudron's comments on v14.
v16-v15
- Address Eelco Chaudron's comments on v15.
- Add two test cases.
v17-v16
- Address Eelco Chaudron's comments on v16.
- Move struct dpif_offload_api from struct dpif_class to struct dpif.
v18-v17
- Rename dpif_offload_api to dpif_offload_class.
- Add init and destroy callbacks in dpif_offload_class. They are called
when registering dpif_offload_class.
v19-18
- Fix a bug that psample_sock is destroyed when last bridge is deleted.
v20-19
- Move buf_stub to struct dpif_offload_sflow avoid garbage values when
ofproto proceses the sampled packet.
v21-20
- Remove netdev dummy for dpif-offload according to Eelco's comment.
v22-21
- Address Ilya's comments:
- Remove dpif-offload-provider layer.
- Remove process_offload_sflow and reuse upcall_receive.
- Introduce sample id pool.
- Introduce netdev_offload_recv.
v23-22
- Address Ilya's comments:
- Add struct flow in struct dpif_upcall.
- Add handler id in recv() and recv_wait().
- misc changes.
v24-23
- Fix checkpath and actions errors.
v25-24
- Address Eelco's comments:
- Add tunnel test.
- Change sample group id and sample info to 1:1 mapping.
- Move sample group id from tcf_id to ufid_to_tc_data.
- misc changes.
v26-25
- Address Eelco's comments:
- Rename actions to userspace_actions.
- Add in tunnel test.
v27-26
- Address Eelco's comments:
- Introduce nullable_xmemdup() and flow_tnl_copy().
- Improve sgid node locking.
- Improve comments and documents.
- Add support for multiple sgids.
- Improve test cases.
- misc changes.
v28-27
- Apply Eelco's three diff files directly.
v29-28
- Address Ilya's comments.
Chris Mi (8):
compat: Add psample and tc sample action defines for older kernels
ovs-kmod-ctl: Load kernel module psample
netdev-offload-tc: Introduce group ID management API
netdev-offload-tc: Add sample offload API for TC
netdev-offload: Add netdev offload recv and recv_wait APIs
dpif-netlink: Add netdev offload recv in normal recv upcalls
netdev-offload-tc: Add offload support for sFlow
system-offloads-traffic.at: Add sFlow offload test cases
Documentation/howto/tc-offload.rst | 24 ++
NEWS | 2 +
include/linux/automake.mk | 10 +-
include/linux/psample.h | 62 +++
include/linux/tc_act/tc_sample.h | 25 ++
lib/dpif-netlink.c | 41 +-
lib/dpif.h | 6 +-
lib/flow.h | 2 +-
lib/netdev-offload-provider.h | 30 ++
lib/netdev-offload-tc.c | 612 +++++++++++++++++++++++++++--
lib/netdev-offload.c | 41 +-
lib/netdev-offload.h | 5 +
lib/packets.h | 2 +-
lib/tc.c | 63 ++-
lib/tc.h | 6 +
lib/util.c | 6 +
lib/util.h | 1 +
ofproto/ofproto-dpif-upcall.c | 16 +-
tests/system-common-macros.at | 13 +
tests/system-offloads-traffic.at | 177 +++++++++
utilities/ovs-kmod-ctl.in | 14 +
21 files changed, 1113 insertions(+), 45 deletions(-)
create mode 100644 include/linux/psample.h
create mode 100644 include/linux/tc_act/tc_sample.h
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