On Thu, May 14, 2020 at 10:29:31PM +0200, Olivier Matz wrote: > Hi Nithin, > > On Tue, May 05, 2020 at 11:49:20AM +0530, Nithin Dabilpuram wrote: > > On Mon, May 04, 2020 at 02:27:35PM +0200, Olivier Matz wrote: > > > On Mon, May 04, 2020 at 03:34:57PM +0530, Nithin Dabilpuram wrote: > > > > On Mon, May 04, 2020 at 11:16:40AM +0200, Olivier Matz wrote: > > > > > 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 > > > > > > > > <nithind1...@gmail.com> wrote: > > > > > > > > > > > > > > > > > > From: Nithin Dabilpuram <ndabilpu...@marvell.com> > > > > > > > > > > > > > > > > > > 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 <kka...@marvell.com> > > > > > > > > > Signed-off-by: Nithin Dabilpuram <ndabilpu...@marvell.com> > > > > > > > > > > > > > > > > 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? > > > > > > > > Yes. Octeontx2 HW always depends on application knowledge instead of > > > > walking > > > > through all the layers of packet data in Tx to identify what packet it > > > > is > > > > and where the l2, l3, l4 headers start for performance reasons. > > > > > > > > I believe there are other hardware too that have the same expectation > > > > and hence we have a need for PKT_TX_IPv4, PKT_TX_IPv6 kind of flags. > > > > > > > > Hence we want to make use of mbuf:tx_offload field and PKT_TX_* flags > > > > for identifying the packet and knowing what are its l2,l3,l4 offsets. > > > > > > The objective is to give an indication to the hardware that the packet > > > has: > > > - an 802.1q header at offset X for PKT_TX_MARK_VLAN_DEI > > > - an IP/IPv6 header at offset X for PKT_TX_MARK_IP_DSCP > > > - an IP/IPv6 header at offset X and a TCP/SCTP header at offset Y for > > > PKT_TX_MARK_IP_ECN > > > > > > Just to be sure I'm getting the point, would it also work if with flags > > > like this: > > > > > > - an 802.1q header at offset X for PKT_TX_HAS_VLAN > > > - an IP/IPv6 header at offset X for PKT_TX_IPv4 or PKT_TX_IPv6 > > > - a TCP/SCTP header at offset Y for PKT_TX_TCP/PKT_TX_SCTP (implies > > > PKT_TX_IPv4 or PKT_TX_IPv6) > > > > > > The underlying question is: do we need the flags to only describe the > > > content of the packet or do the flag also indicate that an action has to > > > be done? > > > > If we don't have a specific action based flag, then in future it might > > collide > > with other functionality and we will not be able to choose that specific > > offload. All the existing features are having specific flags, like TSO, > > CSUM. > > > > RFC wise, even when marking in enabled and packet is coloured, not all > > packets > > can be marked. > > For example when IP DSCP marking(RFC 2597) is enabled, marking is defined > > only with below 12 code points out of 64 code points (6 bits of DSCP). > > > > Class 1 Class 2 Class 3 Class 4 > > +----------+----------+----------+----------+ > > Low Drop Prec | 001010 | 010010 | 011010 | 100010 | > > Medium Drop Prec | 001100 | 010100 | 011100 | 100100 | > > High Drop Prec | 001110 | 010110 | 011110 | 100110 | > > +----------+----------+----------+----------+ > > > > All other combinations of DSCP value can be used for some other purposes > > and hence packets with those values shouldn't be marked. > > Similar is the case with IP ECN marking for TCP/SCTP(RFC 3168). > > > > Having PMD or HW to check if the packet falls in the said class and then do > > marking will impact performance. Since application actually fills those > > values > > in packet, it will be more easy for them to say. > > > > > > > > > > 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? > > > > > > > > Packet is coloured based on Single Rate[1] or Dual Rate[2] Shaping > > > > result > > > > and packet color determines traffic class. The exact behavior of > > > > packet color to traffic class mapping is mentioned in TM spec based on > > > > few other RFC's. > > > > > > > > [1] > > > > https://urldefense.proofpoint.com/v2/url?u=https-3A__tools.ietf.org_html_rfc2697&d=DwIBAg&c=nKjWec2b6R0mOyPaz7xtfQ&r=FZ_tPCbgFOh18zwRPO9H0yDx8VW38vuapifdDfc8SFQ&m=pJDciSXpMy6TawycjvpYj_Jq5M5j_ywqhU8-keRI_ac&s=05emGNkz3Qat3dtZIbEsmQDC5y9-tU9yItHX0x1aaJU&e= > > > > > > > > [2] > > > > https://urldefense.proofpoint.com/v2/url?u=https-3A__tools.ietf.org_html_rfc2698&d=DwIBAg&c=nKjWec2b6R0mOyPaz7xtfQ&r=FZ_tPCbgFOh18zwRPO9H0yDx8VW38vuapifdDfc8SFQ&m=pJDciSXpMy6TawycjvpYj_Jq5M5j_ywqhU8-keRI_ac&s=3VN2dIGSDt4vWM-FpPOOf-8SeVShl_t7QpXRU6Zw460&e= > > > > > > > > > > OK, so the traffic class does not depend on the packet type? > > Yes it doesn't. But where to update the traffic class is specific to packet > > type like DEI bit in VLAN or ECN field in IPv4/IPv6 or DSCP field in > > IPv4/IPv6. > > Also ECN marking is only valid for TCP/SCTP packets. > > > > > > > > > > > > > > > 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? > > > > > > > > Yes, I thought PMD's need to support both. > > > > I'm fine adding specific feature flag for the offload flags alone > > > > if you insist or if there are other PMD's which don't need the offload > > > > flags > > > > for packet marking. I was not able to find out about other PMD's as > > > > none of the existing PMD's support packet marking. > > > > > > Do you suggest that the behavior of the traffic manager marking should > > > be: > > > > > > a- the hardware tries to recognize tx packets, and mark them > > > accordingly. What packets are recognized depend on hardware. > > > b- if the mbuf has a specific flag, it helps the PMD and hardware to > > > recognize packets, so it can mark packets. > > > > > > For an application, a- is difficult to apprehend as it will be dependent > > > on hardware. > > > > > > Or do you suggest that packets should only be marked if there is a mbuf > > > flag? (only b-) > > Yes, I believe b- is the right thing. > > > > > > > > Do you confirm that there is no support at all for this feature today? > > > I mean, what was the usage of rte_tm_mark_vlan_dei() these last 3 years? > > > > Yes, it was not implemented/used. Because of such reasons, rte_tm.h is > > supposed to be experimental but was mistakenly marked stable. > > You can see related discussion in below threads about marking rte_tm.h > > experimental again in v20.11. > > https://urldefense.proofpoint.com/v2/url?u=https-3A__mails.dpdk.org_archives_dev_2020-2DApril_164970.html&d=DwIBAg&c=nKjWec2b6R0mOyPaz7xtfQ&r=FZ_tPCbgFOh18zwRPO9H0yDx8VW38vuapifdDfc8SFQ&m=myqGwnIHNjN9IP7urxcVAB384qKoxlmm00p1gS7ttbw&s=-o2E-F9aHy3mrQw6xgO__RPXY9t8s3yjJn81X6Ius3k&e= > > > > https://urldefense.proofpoint.com/v2/url?u=https-3A__mails.dpdk.org_archives_dev_2020-2DMay_166221.html&d=DwIBAg&c=nKjWec2b6R0mOyPaz7xtfQ&r=FZ_tPCbgFOh18zwRPO9H0yDx8VW38vuapifdDfc8SFQ&m=myqGwnIHNjN9IP7urxcVAB384qKoxlmm00p1gS7ttbw&s=gTKSzMmlhE75x4TP8IJB7NP5MVO-zxjmNRQ9bZ6MxwI&e= > > > > Thank you for the explanations. I also think b- is a better choice. > > I don't see any better approach than having a mbuf flag. However, I'm > still not fully convinced that a dynamic flag won't do the job. Taking > 3 additional flags (among 18 remaing) for this feature also means that > we have 3 flags less for dynamic flags for all applications, even for > applications that will not use this feature. > > Would it be a problem to use a dynamic flag in this case? Since packet marking feature itself is already part of spec, if we move the flags to PMD specific dynamic flag, then it creates a confusion.
It is not the case of a custom feature supported by a specific PMD. I believe when other PMD's implement packet marking, the same flags will suffice. > > Thanks, > Olivier > > > > > > Thanks > > Nithin > > > > > > > > Thanks, > > > Olivier > > > > > > > > > > > > > > > > > > > > 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? > > > > > > > > I meant by setting the flag, a packet has VLAN header adhering to IEEE > > > > 802.1Q spec. > > > > > > > > > > > > > > > > > > + * b) Application should also set mbuf.l2_len where 802.1Q > > > > > > > > > header is > > > > > > > > > + * at (mbuf.l2_len - 6) offset. > > > > > > > > > > Why mbuf.l2_len - 6 ? > > > > L2 header when VLAN header is preset will be > > > > {custom header 'X' Bytes}:{Ethernet SRC+DST (12B)}:{VLAN Header > > > > (4B)}:{Ether Type (2B)} > > > > l2_len = X + 12 + 4 + 2 > > > > So, VLAN header starts at (l2_len - 6) bytes. > > > > > > > > > > > > > > > > > > + * 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. > > > > Ack, will fix in V2. > > > > > > > > > > > > > > > > > > > > > > > + > > > > > > > > > +/** > > > > > > > > > * 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 > > > > > > > > >