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From: Ori Kam <orika@nvidia.com>
To: Ferruh Yigit <ferruh.yigit@amd.com>,
	Dariusz Sosnowski <dsosnowski@nvidia.com>,
	"cristian.dumitrescu@intel.com" <cristian.dumitrescu@intel.com>,
	"andrew.rybchenko@oktetlabs.ru" <andrew.rybchenko@oktetlabs.ru>,
	"stephen@networkplumber.org" <stephen@networkplumber.org>,
	"NBU-Contact-Thomas Monjalon (EXTERNAL)" <thomas@monjalon.net>
Cc: "dev@dpdk.org" <dev@dpdk.org>, Raslan Darawsheh <rasland@nvidia.com>
Subject: RE: [PATCH v2 1/4] ethdev: introduce encap hash calculation
Date: Sun, 11 Feb 2024 07:29:34 +0000	[thread overview]
Message-ID: <MW2PR12MB4666BE1F8D4E64E034E847C4D6492@MW2PR12MB4666.namprd12.prod.outlook.com> (raw)
In-Reply-To: <50189a77-2c1f-4b31-935d-506fa98d22af@amd.com>

Hi Ferruh,

> -----Original Message-----
> From: Ferruh Yigit <ferruh.yigit@amd.com>
> Sent: Thursday, February 8, 2024 7:13 PM
> To: Ori Kam <orika@nvidia.com>; Dariusz Sosnowski
> 
> On 2/8/2024 9:09 AM, Ori Kam wrote:
> > During encapsulation of a packet, it is possible to change some
> > outer headers to improve flow destribution.
> > For example, from VXLAN RFC:
> > "It is recommended that the UDP source port number
> > be calculated using a hash of fields from the inner packet --
> > one example being a hash of the inner Ethernet frame's headers.
> > This is to enable a level of entropy for the ECMP/load-balancing"
> >
> > The tunnel protocol defines which outer field should hold this hash,
> > but it doesn't define the hash calculation algorithm.
> >
> > An application that uses flow offloads gets the first few packets
> > (exception path) and then decides to offload the flow.
> > As a result, there are two
> > different paths that a packet from a given flow may take.
> > SW for the first few packets or HW for the rest.
> > When the packet goes through the SW, the SW encapsulates the packet
> > and must use the same hash calculation as the HW will do for
> > the rest of the packets in this flow.
> >
> > the new function rte_flow_calc_encap_hash can query the hash value
> > fromm the driver for a given packet as if the packet was passed
> > through the HW.
> >
> > Signed-off-by: Ori Kam <orika@nvidia.com>
> > Acked-by: Dariusz Sosnowski <dsosnowski@nvidia.com>
> >
> 
> <...>
> 
> > +int
> > +rte_flow_calc_encap_hash(uint16_t port_id, const struct rte_flow_item
> pattern[],
> > +			 enum rte_flow_encap_hash_field dest_field, uint8_t
> hash_len,
> > +			 uint8_t *hash, struct rte_flow_error *error)
> > +{
> > +	int ret;
> > +	struct rte_eth_dev *dev;
> > +	const struct rte_flow_ops *ops;
> > +
> > +	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
> > +	ops = rte_flow_ops_get(port_id, error);
> > +	if (!ops || !ops->flow_calc_encap_hash)
> > +		return rte_flow_error_set(error, ENOTSUP,
> > +
> RTE_FLOW_ERROR_TYPE_UNSPECIFIED, NULL,
> > +					  "calc encap hash is not supported");
> > +	if ((dest_field == RTE_FLOW_ENCAP_HASH_FIELD_SRC_PORT &&
> hash_len != 2) ||
> > +	    (dest_field == RTE_FLOW_ENCAP_HASH_FIELD_NVGRE_FLOW_ID
> && hash_len != 1))
> >
> 
> If there is a fixed mapping with the dest_field and the size, instead of
> putting this information into check code, what do you think to put it
> into the data structure?
> 
> I mean instead of using enum for dest_filed, it can be a struct that is
> holding enum and its expected size, this clarifies what the expected
> size for that field.
> 

From my original email I think we only need the type, we don't need the size.
On the RFC thread there was an objection. So I added the size, 
If you think it is not needed lets remove it.

> > +		return rte_flow_error_set(error, EINVAL,
> > +
> RTE_FLOW_ERROR_TYPE_UNSPECIFIED, NULL,
> > +					  "hash len doesn't match the
> requested field len");
> > +	dev = &rte_eth_devices[port_id];
> > +	ret = ops->flow_calc_encap_hash(dev, pattern, dest_field, hash,
> error);
> >
> 
> 'hash_len' is get by API, but it is not passed to dev_ops, does this
> mean this information hardcoded in the driver as well, if so why
> duplicate this information in driver instead off passing hash_len to driver?

Not sure I understand, like I wrote above this is pure verification from my point of view.
The driver knows the size based on the dest.

> 
> 
> > +	return flow_err(port_id, ret, error);
> > +}
> > diff --git a/lib/ethdev/rte_flow.h b/lib/ethdev/rte_flow.h
> > index 1267c146e5..2bdf3a4a17 100644
> > --- a/lib/ethdev/rte_flow.h
> > +++ b/lib/ethdev/rte_flow.h
> > @@ -6783,6 +6783,57 @@ rte_flow_calc_table_hash(uint16_t port_id,
> const struct rte_flow_template_table
> >  			 const struct rte_flow_item pattern[], uint8_t
> pattern_template_index,
> >  			 uint32_t *hash, struct rte_flow_error *error);
> >
> > +/**
> > + * @warning
> > + * @b EXPERIMENTAL: this API may change without prior notice.
> > + *
> > + * Destination field type for the hash calculation, when encap action is
> used.
> > + *
> > + * @see function rte_flow_calc_encap_hash
> > + */
> > +enum rte_flow_encap_hash_field {
> > +	/* Calculate hash placed in UDP source port field. */
> > +	RTE_FLOW_ENCAP_HASH_FIELD_SRC_PORT,
> > +	/* Calculate hash placed in NVGRE flow ID field. */
> > +	RTE_FLOW_ENCAP_HASH_FIELD_NVGRE_FLOW_ID,
> > +};
> >
> 
> Indeed above enum represents a field in a network protocol, right?
> Instead of having a 'RTE_FLOW_ENCAP_HASH_' specific one, can re-using
> 'enum rte_flow_field_id' work?

Since the option are really limited and defined by standard, I prefer to have dedicated options. 


Best,
Ori

  reply	other threads:[~2024-02-11  7:29 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-28  9:39 [PATCH 0/4] " Ori Kam
2024-01-28  9:39 ` [PATCH 1/4] ethdev: " Ori Kam
2024-02-01  8:40   ` Ori Kam
2024-02-06 22:39   ` Thomas Monjalon
2024-02-07  6:56     ` Ori Kam
2024-02-07  9:25       ` Thomas Monjalon
2024-01-28  9:39 ` [PATCH 2/4] net/mlx5/hws: introduce encap entropy hash calculation API Ori Kam
2024-01-28  9:39 ` [PATCH 3/4] net/mlx5: add calc encap hash support Ori Kam
2024-01-28  9:39 ` [PATCH 4/4] app/testpmd: add encap hash calculation Ori Kam
2024-01-31 18:30 ` [PATCH 0/4] introduce " Dariusz Sosnowski
2024-02-08  9:09 ` [PATCH v2 1/4] ethdev: " Ori Kam
2024-02-08  9:09   ` [PATCH v2 2/4] net/mlx5/hws: introduce encap entropy hash calculation API Ori Kam
2024-02-08  9:09   ` [PATCH v2 3/4] net/mlx5: add calc encap hash support Ori Kam
2024-02-08  9:09   ` [PATCH v2 4/4] app/testpmd: add encap hash calculation Ori Kam
2024-02-08 17:13   ` [PATCH v2 1/4] ethdev: introduce " Ferruh Yigit
2024-02-11  7:29     ` Ori Kam [this message]
2024-02-12 17:05       ` Ferruh Yigit
2024-02-12 18:44         ` Ori Kam
2024-02-12 20:09           ` Ferruh Yigit
2024-02-13  7:05             ` Ori Kam
2024-02-13 13:48 ` [PATCH v3 " Ori Kam
2024-02-13 13:48   ` [PATCH v3 2/4] net/mlx5/hws: introduce encap entropy hash calculation API Ori Kam
2024-02-13 13:48   ` [PATCH v3 3/4] net/mlx5: add calc encap hash support Ori Kam
2024-02-13 13:48   ` [PATCH v3 4/4] app/testpmd: add encap hash calculation Ori Kam
2024-02-13 14:16 ` [PATCH v4 1/4] ethdev: introduce " Ori Kam
2024-02-13 14:16   ` [PATCH v4 2/4] net/mlx5/hws: introduce encap entropy hash calculation API Ori Kam
2024-02-13 14:16   ` [PATCH v4 3/4] net/mlx5: add calc encap hash support Ori Kam
2024-02-13 14:16   ` [PATCH v4 4/4] app/testpmd: add encap hash calculation Ori Kam
2024-02-13 15:45     ` Ferruh Yigit
2024-02-13 15:45   ` [PATCH v4 1/4] ethdev: introduce " Ferruh Yigit
2024-02-13 15:45     ` Ferruh Yigit

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