+Shahaf,
Hi Maxime,
On Mon, Sep 13, 2021 at 11:41:04AM +0200, Maxime Coquelin wrote:
> Hi Nélio,
>
> On 9/10/21 4:16 PM, Nélio Laranjeiro wrote:
> > On Fri, Sep 10, 2021 at 01:06:53PM +0300, Andrew Rybchenko wrote:
> >> On 9/10/21 12:57 PM, Maxime Coquelin wrote:
> >>>
> >>>
> >>> On 9/10/21 11:51 AM, Andrew Rybchenko wrote:
> >>>> On 9/10/21 12:17 PM, Maxime Coquelin wrote:
> >>>>> port_rss_hash_key_update() initializes rss_conf with the
> >>>>> RSS hash type and key provided by the user, but it calls
> >>>>> rte_eth_dev_rss_hash_conf_get() before calling
> >>>>> rte_eth_dev_rss_hash_update(), which overides the parsed
> >>>>> config with current NIC's config.
> >>>>>
> >>>>> While the RSS key value is set again after, this is not
> >>>>> the case of the key length and the type of hash.
> >>>>>
> >>>>> There is no need to read the RSS config from the NIC, let's
> >>>>> just try to set the user defined one.
> >>>>>
> >>>>> Fixes: 8205e241b2b0 ("app/testpmd: add missing type to RSS hash
> >>>>> commands")
> >>>>> Cc: sta...@dpdk.org
> >>>>> Cc: nelio.laranje...@6wind.com
> >>>>>
> >>>>> Signed-off-by: Maxime Coquelin <maxime.coque...@redhat.com>
> >>>>> ---
> >>>>> app/test-pmd/config.c | 8 ++------
> >>>>> 1 file changed, 2 insertions(+), 6 deletions(-)
> >>>>>
> >>>>> diff --git a/app/test-pmd/config.c b/app/test-pmd/config.c
> >>>>> index 31d8ba1b91..451bda53b1 100644
> >>>>> --- a/app/test-pmd/config.c
> >>>>> +++ b/app/test-pmd/config.c
> >>>>> @@ -2853,18 +2853,14 @@ port_rss_hash_key_update(portid_t port_id, char
> >>>>> rss_type[], uint8_t *hash_key,
> >>>>> int diag;
> >>>>> unsigned int i;
> >>>>>
> >>>>> - rss_conf.rss_key = NULL;
> >>>>> + rss_conf.rss_key = hash_key;
> >>>>> rss_conf.rss_key_len = hash_key_len;
> >>>>> rss_conf.rss_hf = 0;
> >>>>> for (i = 0; rss_type_table[i].str; i++) {
> >>>>> if (!strcmp(rss_type_table[i].str, rss_type))
> >>>>> rss_conf.rss_hf = rss_type_table[i].rss_type;
> >>>>> }
> >>>>> - diag = rte_eth_dev_rss_hash_conf_get(port_id, &rss_conf);
> >>>>> - if (diag == 0) {
> >>>>> - rss_conf.rss_key = hash_key;
> >>>>> - diag = rte_eth_dev_rss_hash_update(port_id, &rss_conf);
> >>>>> - }
> >>>>> + diag = rte_eth_dev_rss_hash_update(port_id, &rss_conf);
> >>>>
> >>>> I'm not 100% sure, but I'd say the intent above could be
> >>>> to update key only as the function name says. I.e. keep
> >>>> rss_hf as is. That could be the reason to get first.
> >
> > True,
> >
> >>> I think that was the intial purpose of the command, but patch
> >>> 8205e241b2b0 added setting the hash type as mandatory. There are
> >>> no other command to configure the hash type from testpmd AFAICT.
> >
> > Also for the same initial purpose, some NIC have an hash key per
> > protocol, by default it uses the same key for all of them but it can be
> > configured individually making for example key0 for all protocols expect
> > IPv4 which uses key1.
>
> Thanks for the info, I have looked at most drivers but didn't found one
> that support this feature, could you give some pointer?
Well, I have done the modification at that time for MLX5 PMD, since I
left DPDK in 2018 I don't know if they still support such configuration
from this API or if they fully moved to rte_flow.
> Given how the drivers implément the callback, do you agree with the fix,
> or do you have something else in mind?
I cannot answer if this get() is mandatory, this predates my arrival on
DPDK (original commit written in 2014), looking at DPDK state on
commit f79959ea1504 ("app/testpmd: allow to configure RSS hash key").
Maybe someone from Intel can help, eventually you can contact PMD
maintainers to review this patch.
Regards,
Nélio
> Thanks,
> Maxime
>
> >>> Also, even without 8205e241b2b0, the function was broken because the
> >>> key length was overiden.
> >>
> >> I see, many thanks for explanations.
> >
>
--
Nélio Laranjeiro
6WIND
