On 10/16/2020 11:04 AM, oulijun wrote:
在 2020/10/16 7:53, Ferruh Yigit 写道:
On 10/16/2020 12:21 AM, Ophir Munk wrote:
From: Ferruh Yigit <ferruh.yi...@intel.com>
On 10/15/2020 1:41 PM, Lijun Ou wrote:
When start the testpmd, the pmd driver initializes the RSS
configuration. Generally, the recommended RSS hash key is used as
the default key in the driver. In addition, the default key is
different from the default RSS flow in testpmd without specifying
RSS hash key. So. if you do not specify the RSS key when creating
an RSS rule, the testpmd uses the default key as the default RSS
key of the RSS rule. As a result, you may mistakenly consider that
the RSS key in use is the valid default key of the NIC, actually,
the key and the valid default key of the NIC are two values.
Consider the follow usage with testpmd:
1. first, startup testpmd:
testpmd> show port 0 rss-hash key
RSS functions:
all ipv4-frag ipv4-other ipv6-frag ipv6-other ip RSS key:
-
6D5A56DA255B0EC24167253D43A38FB0D0CA2BCBAE7B30B477CB2DA3803
0F
-20C6A42B73BBEAC01FA
2. create a rss rule
testpmd> flow create 0 ingress pattern eth / ipv4 / udp / end
testpmd> actions rss \
types ipv4-udp end queues end / end
3. show rss-hash key
testpmd> show port 0 rss-hash key
RSS functions:
all ipv4-udp udp
RSS key:
-
74657374706D6427732064656661756C74205253532068617368206B65792C
206F
-76657272696465
In order to solve the above problems, it use the NIC valid default
RSS key instead of the testpmd dummy RSS key in the flow
configuration when the RSS key is not specified in the flow rule.
If the NIC RSS key is invalid, it will use testpmd dummy RSS key as the
default key.
Fixes: ac8d22de2394 ("ethdev: flatten RSS configuration in flow
API")
Cc: sta...@dpdk.org
Signed-off-by: Lijun Ou <ouli...@huawei.com>
Reviewed-by: Phil Yang <phil.y...@arm.com>
---
V4->V5:
-rewrite the commit log
-add reviewed-by
Hi Lijun,
There were multiple other comments, it seems they are not addressed
but only updated the commit log, can you please check comments to
prev versions.
Before going into the details, my question was what happens if
default key not provided at all?
It seems this has been already tried by Ophir [1], later reverted
back [2] bringing the initial issue back.
According commit, the reason of revert is to support following
command:
"flow create 0 <pattern> actions rss queues 0 1 end key_len 40 / end"
@Ophir, @Lijun,
Can we ignore the 'key_len' if the 'key' is not supported and solve
current issue as initially intended ([1])?
Hi, Ferruh
I have discussed with Phil Yang about the problem in [1]. I think
there may be other problems with the idea and there is no better
solution. and we need to remove key_len definition from rte_rss_conf
structure. They don't have a plan. And [1] was eventually reverted.
Why ignoring 'key_len' (set it to zero) when there is no 'key'
provided doesn't work?
What do you think [1] + following update, will it work?
diff --git a/lib/librte_ethdev/rte_flow.c b/lib/librte_ethdev/rte_flow.c
index ee4f3464fe..e7789c87b3 100644
--- a/lib/librte_ethdev/rte_flow.c
+++ b/lib/librte_ethdev/rte_flow.c
@@ -535,7 +535,7 @@ rte_flow_conv_action_conf(void *buf, const size_t
size,
}),
size > sizeof(*dst.rss) ? sizeof(*dst.rss) :
size);
off = sizeof(*dst.rss);
- if (src.rss->key_len) {
+ if (src.rss->key_len && src.rss->key) {
off = RTE_ALIGN_CEIL(off, sizeof(*dst.rss->key));
tmp = sizeof(*src.rss->key) * src.rss->key_len;
if (size >= off + tmp)
Ferruh, your suggestion ([1] + update) looks correct. I also verified it on
mlx5 PMD.
Advantage: it's a generic fix for all dpdk applications using rte_flows (not
just testpmd).
It reduces code.
With this fix the responsibility of handling key==NULL and/or len==0 is moved
to the PMDs (which is good).
With regard to Lijun patch - I liked the approach of overriding the default
testpmd key with the default PMD key.
But it only addresses testpmd. More code was added.
It seems OK to call rte_eth_dev_rss_hash_conf_get() as part of parsing RSS,
but it would feel more confident if we could confirm it for all the PMDs (by
testing) or at least review the PMDs rss_hash_conf_get() implementations.
Lijun's idea can work. There was a problem in implementation related to the
key size assumption, which can be fixed.
Even it is fixed, when user gives a rss rule without a key, we are getting key
from device and feeding same key back to device, this is unnecessary I think.
When user didn't provide a key, rss rule shouldn't touch the key at all.
Do you mean that the driver should not configure the key to the hardware when
the RSS key is not specified?
We are talking about 'key' in RSS rte flow rule, not generally configuring the
device for RSS.
If a specific rss rte flow rule, lets say to filter some defined packets to some
specific queues, don't have 'key' as a part of rule, I am suggesting not touch
'key' configuration of the device.
If so, we cannot identify when the user does not specify the RSS key to
determine whether to configure the key.
I think we can. If the rule has 'key' attribute, driver can use that key to
program the device, if 'key' attribute is missing, don't do anything related to
the rss key.
In hardware design, most vendors do not configure keys for hardware
independently, which may be associated with other RSS config parameters.
I think it would be reasonable for us to reconfigure the RSS key with the
default value configured and valid in the hardware as the default value if the
user does not specify the RSS key.
There are already APIs to update the RSS configuration, like RSS key, hash
functions etc.. They are independent from the rte flow RSS rule.
Application should configure RSS according needs using those APIs.
The question here is about each RSS rte flow rule that can update the key. Am I
missing something?
Complication was when user provides key_len without a key, I think both
ignoring or returning error in this case is OK.
I agree. However, I think it is meaningless to expose the RSS key length to
users. Do you consider deleting the RSS key length directly?
Isn't both 'key' and 'key_len' needed to program the RSS key? Can the driver
know the size of the 'key' without 'key_len'?
And driver should verify these provided values.
