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[2a01:cb0c:5:a600:3456:36f7:e65e:d1a0]) by smtp.gmail.com with ESMTPSA id a67sm13182764wmc.30.2020.05.04.02.16.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 04 May 2020 02:16:41 -0700 (PDT) Date: Mon, 4 May 2020 11:16:40 +0200 From: Olivier Matz To: Nithin Dabilpuram Cc: Jerin Jacob , Nithin Dabilpuram , Thomas Monjalon , Ferruh Yigit , Andrew Rybchenko , Ori Kam , Cristian Dumitrescu , Anatoly Burakov , John McNamara , Marko Kovacevic , dpdk-dev , Jerin Jacob , Krzysztof Kanas Message-ID: <20200504091640.GC6327@platinum> References: <20200417072254.11455-1-nithind1988@gmail.com> <20200504080634.GB6327@platinum> <20200504082706.GA6153@outlook.office365.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200504082706.GA6153@outlook.office365.com> User-Agent: Mutt/1.10.1 (2018-07-13) Subject: Re: [dpdk-dev] [EXT] Re: [PATCH 1/3] mbuf: add Tx offloads for packet marking X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On Mon, May 04, 2020 at 01:57:06PM +0530, Nithin Dabilpuram wrote: > Hi Olivier, > > On Mon, May 04, 2020 at 10:06:34AM +0200, Olivier Matz wrote: > > External Email > > > > ---------------------------------------------------------------------- > > Hi, > > > > On Fri, May 01, 2020 at 04:48:21PM +0530, Jerin Jacob wrote: > > > On Fri, Apr 17, 2020 at 12:53 PM Nithin Dabilpuram > > > wrote: > > > > > > > > From: Nithin Dabilpuram > > > > > > > > Introduce PKT_TX_MARK_IP_DSCP, PKT_TX_MARK_IP_ECN > > > > and PKT_TX_MARK_VLAN_DEI Tx offload flags to support > > > > packet marking. > > > > > > > > When packet marking feature in Traffic manager is enabled, > > > > application has to the use the three new flags to indicate > > > > to PMD on whether packet marking needs to be enabled on the > > > > specific mbuf or not. By setting the three flags, it is > > > > assumed by PMD that application has already verified the > > > > applicability of marking on that specific packet and > > > > PMD need not perform further checks as per RFC. > > > > > > > > Signed-off-by: Krzysztof Kanas > > > > Signed-off-by: Nithin Dabilpuram > > > > > > None of the ethdev TM driver implementations has supported packet > > > marking support. > > > rte_tm and rte_mbuf maintainers(Christian, Oliver), Could you review this patch? > > > > As you know, the number of mbuf flags is limited (only 18 bits are > > remaining), so I think we should use them with care, i.e. for features > > that are generic enough. > > I agree, but I believe this is one of the basic flags needed like other > Tx checksum offload flags (like PKT_TX_IP_CKSUM, PKT_TX_IPV4, etc) which > are needed to identify on which packets HW should/can apply packet marking. PKT_TX_IP_CKSUM tells the hardware to offload the checksum calculation. This is pretty straightforward and there is no other dependency than the offload feature advertised by the PMD. I'm sorry, I have not a lot of experience with rte_tm.h, so it's difficult for me to have a global view of what is done for instance when PKT_TX_MARK_VLAN_DEI is set, and what happens when it is not set. Can you confirm that my understanding below is correct? (or correct me where I'm wrong) Before your patch: - the application enables the port and traffic manager on it - the application calls rte_tm_mark_vlan_dei() to select which traffic class must be marked - when a packet is transmitted, the traffic class is determined by the hardware, and if the hardware recognizes a VLAN packet, the VLAN DEI bit is set depending on traffic class The problem is for packets that cannot be recognized by the hardware, correct? So your patch is a way to force the hardware to recognize mark set the VLAN DEI on packets that are not recognized as VLAN packets? How the is traffic class of the packet determined? > > From what I understand, this feature is bound to octeontx2, so using a > > mbuf dynamic flag would make more sense here. There are some examples in > > dpdk repository, just grep for "dynflag". > > This is not octeontx2 specific flag but any "packet marking feature" enabled > PMD would need these flags to identify on which packets marking needs to be > done. This is the first PMD that supports packet marking feature and > hence it was not exposed earlier. > > For example to mark VLAN DEI, PMD cannot always assume that there is preexisting > VLAN header from Byte 12 as there is no gaurantee that ethernet header > always starts at Byte 0 (Custom headers before ethernet hdr). > > > > > Also, I think that the feature availability should be advertised through > > an ethdev offload, so an application can know at initialization time > > that these flags can be used. > > Feature availablity is already part of TM spec in rte_tm.h > struct rte_tm_capabilities:mark_vlan_dei_supported > struct rte_tm_capabilities:mark_ip_ecn_[sctp|tcp]_supported > struct rte_tm_capabilities:mark_ip_dscp_supported Does this mean that any driver advertising this existing feature flag has to support the new mbuf flags too? Shouldn't we have a specific feature for it? Please also see few comments below. > > > > --- > > > > doc/guides/nics/features.rst | 14 ++++++++++++++ > > > > lib/librte_mbuf/rte_mbuf.c | 6 ++++++ > > > > lib/librte_mbuf/rte_mbuf_core.h | 36 ++++++++++++++++++++++++++++++++++-- > > > > 3 files changed, 54 insertions(+), 2 deletions(-) > > > > > > > > diff --git a/doc/guides/nics/features.rst b/doc/guides/nics/features.rst > > > > index edd21c4..bc978fb 100644 > > > > --- a/doc/guides/nics/features.rst > > > > +++ b/doc/guides/nics/features.rst > > > > @@ -913,6 +913,20 @@ Supports to get Rx/Tx packet burst mode information. > > > > * **[implements] eth_dev_ops**: ``rx_burst_mode_get``, ``tx_burst_mode_get``. > > > > * **[related] API**: ``rte_eth_rx_burst_mode_get()``, ``rte_eth_tx_burst_mode_get()``. > > > > > > > > +.. _nic_features_traffic_manager_packet_marking_offload: > > > > + > > > > +Traffic Manager Packet marking offload > > > > +-------------------------------------- > > > > + > > > > +Supports enabling a packet marking offload specific mbuf. > > > > + > > > > +* **[uses] mbuf**: ``mbuf.ol_flags:PKT_TX_MARK_IP_DSCP``, > > > > + ``mbuf.ol_flags:PKT_TX_MARK_IP_ECN``, ``mbuf.ol_flags:PKT_TX_MARK_VLAN_DEI``, > > > > + ``mbuf.ol_flags:PKT_TX_IPV4``, ``mbuf.ol_flags:PKT_TX_IPV6``. > > > > +* **[uses] mbuf**: ``mbuf.l2_len``. > > > > +* **[related] API**: ``rte_tm_mark_ip_dscp()``, ``rte_tm_mark_ip_ecn()``, > > > > + ``rte_tm_mark_vlan_dei()``. > > > > + > > > > .. _nic_features_other: > > > > > > > > Other dev ops not represented by a Feature > > > > diff --git a/lib/librte_mbuf/rte_mbuf.c b/lib/librte_mbuf/rte_mbuf.c > > > > index cd5794d..5c6896d 100644 > > > > --- a/lib/librte_mbuf/rte_mbuf.c > > > > +++ b/lib/librte_mbuf/rte_mbuf.c > > > > @@ -880,6 +880,9 @@ const char *rte_get_tx_ol_flag_name(uint64_t mask) > > > > case PKT_TX_SEC_OFFLOAD: return "PKT_TX_SEC_OFFLOAD"; > > > > case PKT_TX_UDP_SEG: return "PKT_TX_UDP_SEG"; > > > > case PKT_TX_OUTER_UDP_CKSUM: return "PKT_TX_OUTER_UDP_CKSUM"; > > > > + case PKT_TX_MARK_VLAN_DEI: return "PKT_TX_MARK_VLAN_DEI"; > > > > + case PKT_TX_MARK_IP_DSCP: return "PKT_TX_MARK_IP_DSCP"; > > > > + case PKT_TX_MARK_IP_ECN: return "PKT_TX_MARK_IP_ECN"; > > > > default: return NULL; > > > > } > > > > } > > > > @@ -916,6 +919,9 @@ rte_get_tx_ol_flag_list(uint64_t mask, char *buf, size_t buflen) > > > > { PKT_TX_SEC_OFFLOAD, PKT_TX_SEC_OFFLOAD, NULL }, > > > > { PKT_TX_UDP_SEG, PKT_TX_UDP_SEG, NULL }, > > > > { PKT_TX_OUTER_UDP_CKSUM, PKT_TX_OUTER_UDP_CKSUM, NULL }, > > > > + { PKT_TX_MARK_VLAN_DEI, PKT_TX_MARK_VLAN_DEI, NULL }, > > > > + { PKT_TX_MARK_IP_DSCP, PKT_TX_MARK_IP_DSCP, NULL }, > > > > + { PKT_TX_MARK_IP_ECN, PKT_TX_MARK_IP_ECN, NULL }, > > > > }; > > > > const char *name; > > > > unsigned int i; > > > > diff --git a/lib/librte_mbuf/rte_mbuf_core.h b/lib/librte_mbuf/rte_mbuf_core.h > > > > index b9a59c8..d9f1290 100644 > > > > --- a/lib/librte_mbuf/rte_mbuf_core.h > > > > +++ b/lib/librte_mbuf/rte_mbuf_core.h > > > > @@ -187,11 +187,40 @@ extern "C" { > > > > /* add new RX flags here, don't forget to update PKT_FIRST_FREE */ > > > > > > > > #define PKT_FIRST_FREE (1ULL << 23) > > > > -#define PKT_LAST_FREE (1ULL << 40) > > > > +#define PKT_LAST_FREE (1ULL << 37) > > > > > > > > /* add new TX flags here, don't forget to update PKT_LAST_FREE */ > > > > > > > > /** > > > > + * Packet marking offload flags. These flags indicated what kind > > > > + * of packet marking needs to be applied on a given mbuf when > > > > + * appropriate Traffic Manager configuration is in place. > > > > + * When user set's these flags on a mbuf, below assumptions are made > > > > + * 1) When PKT_TX_MARK_VLAN_DEI is set, > > > > + * a) PMD assumes pkt to be a 802.1q packet. What does that imply? > > > > + * b) Application should also set mbuf.l2_len where 802.1Q header is > > > > + * at (mbuf.l2_len - 6) offset. Why mbuf.l2_len - 6 ? > > > > + * 2) When PKT_TX_MARK_IP_DSCP is set, > > > > + * a) Application should also set either PKT_TX_IPV4 or PKT_TX_IPV6 > > > > + * to indicate whether if it is IPv4 packet or IPv6 packet > > > > + * for DSCP marking. It should also set PKT_TX_IP_CKSUM if it is > > > > + * IPv4 pkt. > > > > + * b) Application should also set mbuf.l2_len that indicates > > > > + * start offset of L3 header. > > > > + * 3) When PKT_TX_MARK_IP_ECN is set, > > > > + * a) Application should also set either PKT_TX_IPV4 or PKT_TX_IPV6. > > > > + * It should also set PKT_TX_IP_CKSUM if it is IPv4 pkt. > > > > + * b) PMD will assume pkt L4 protocol is either TCP or SCTP and > > > > + * ECN is set to 2'b01 or 2'b10 as per RFC 3168 and hence HW > > > > + * can mark the packet for a configured color. > > > > + * c) Application should also set mbuf.l2_len that indicates > > > > + * start offset of L3 header. > > > > + */ > > > > +#define PKT_TX_MARK_VLAN_DEI (1ULL << 38) > > > > +#define PKT_TX_MARK_IP_DSCP (1ULL << 39) > > > > +#define PKT_TX_MARK_IP_ECN (1ULL << 40) We should have one comment per define. > > > > + > > > > +/** > > > > * Outer UDP checksum offload flag. This flag is used for enabling > > > > * outer UDP checksum in PMD. To use outer UDP checksum, the user needs to > > > > * 1) Enable the following in mbuf, > > > > @@ -384,7 +413,10 @@ extern "C" { > > > > PKT_TX_MACSEC | \ > > > > PKT_TX_SEC_OFFLOAD | \ > > > > PKT_TX_UDP_SEG | \ > > > > - PKT_TX_OUTER_UDP_CKSUM) > > > > + PKT_TX_OUTER_UDP_CKSUM | \ > > > > + PKT_TX_MARK_VLAN_DEI | \ > > > > + PKT_TX_MARK_IP_DSCP | \ > > > > + PKT_TX_MARK_IP_ECN) > > > > > > > > /** > > > > * Mbuf having an external buffer attached. shinfo in mbuf must be filled. > > > > -- > > > > 2.8.4 > > > >