Messages in this thread | | | From | Vinicius Costa Gomes <> | Subject | Re: [v1,net-next, 1/2] ethtool: add setting frame preemption of traffic classes | Date | Fri, 17 Jan 2020 16:03:07 -0800 |
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Hi,
Po Liu <po.liu@nxp.com> writes:
> IEEE Std 802.1Qbu standard defined the frame preemption of port > traffic classes. This patch introduce a method to set traffic > classes preemption. Add a parameter 'preemption' in struct > ethtool_link_settings. The value will be translated to a binary, > each bit represent a traffic class. Bit "1" means preemptable > traffic class. Bit "0" means express traffic class. MSB represent > high number traffic class.
I think that we should keep the concept of 'traffic classes' outside of ethtool. Ethtool should only care about queues (or similar concepts). And unless I am missing something here, what you mean by 'traffic class' here is really a hardware queue.
> > If hardware support the frame preemption, driver could set the > ethernet device with hw_features and features with NETIF_F_PREEMPTION > when initializing the port driver. > > User can check the feature 'tx-preemption' by command 'ethtool -k > devname'. If hareware set preemption feature. The property would > be a fixed value 'on' if hardware support the frame preemption. > Feature would show a fixed value 'off' if hardware don't support > the frame preemption. > > Command 'ethtool devname' and 'ethtool -s devname preemption N' > would show/set which traffic classes are frame preemptable. > > Port driver would implement the frame preemption in the function > get_link_ksettings() and set_link_ksettings() in the struct ethtool_ops. > > Signed-off-by: Po Liu <Po.Liu@nxp.com> > --- > include/linux/netdev_features.h | 5 ++++- > include/uapi/linux/ethtool.h | 5 ++++- > net/core/ethtool.c | 1 + > 3 files changed, 9 insertions(+), 2 deletions(-) > > diff --git a/include/linux/netdev_features.h b/include/linux/netdev_features.h > index 4b19c544c59a..299750a8b414 100644 > --- a/include/linux/netdev_features.h > +++ b/include/linux/netdev_features.h > @@ -80,6 +80,7 @@ enum { > > NETIF_F_GRO_HW_BIT, /* Hardware Generic receive offload */ > NETIF_F_HW_TLS_RECORD_BIT, /* Offload TLS record */ > + NETIF_F_HW_PREEMPTION_BIT, /* Hardware TC frame preemption */ > > /* > * Add your fresh new feature above and remember to update > @@ -150,6 +151,7 @@ enum { > #define NETIF_F_GSO_UDP_L4 __NETIF_F(GSO_UDP_L4) > #define NETIF_F_HW_TLS_TX __NETIF_F(HW_TLS_TX) > #define NETIF_F_HW_TLS_RX __NETIF_F(HW_TLS_RX) > +#define NETIF_F_PREEMPTION __NETIF_F(HW_PREEMPTION) > > /* Finds the next feature with the highest number of the range of start till 0. > */ > @@ -175,7 +177,8 @@ static inline int find_next_netdev_feature(u64 feature, unsigned long start) > /* Features valid for ethtool to change */ > /* = all defined minus driver/device-class-related */ > #define NETIF_F_NEVER_CHANGE (NETIF_F_VLAN_CHALLENGED | \ > - NETIF_F_LLTX | NETIF_F_NETNS_LOCAL) > + NETIF_F_LLTX | NETIF_F_NETNS_LOCAL | \ > + NETIF_F_PREEMPTION) > > /* remember that ((t)1 << t_BITS) is undefined in C99 */ > #define NETIF_F_ETHTOOL_BITS ((__NETIF_F_BIT(NETDEV_FEATURE_COUNT - 1) | \ > diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h > index d4591792f0b4..12ffb34afbfa 100644 > --- a/include/uapi/linux/ethtool.h > +++ b/include/uapi/linux/ethtool.h > @@ -1776,6 +1776,8 @@ enum ethtool_reset_flags { > }; > #define ETH_RESET_SHARED_SHIFT 16 > > +/* Disable preemtion. */ > +#define PREEMPTION_DISABLE 0x0 > > /** > * struct ethtool_link_settings - link control and status > @@ -1886,7 +1888,8 @@ struct ethtool_link_settings { > __s8 link_mode_masks_nwords; > __u8 transceiver; > __u8 reserved1[3]; > - __u32 reserved[7]; > + __u32 preemption; > + __u32 reserved[6]; > __u32 link_mode_masks[0]; > /* layout of link_mode_masks fields: > * __u32 map_supported[link_mode_masks_nwords]; > diff --git a/net/core/ethtool.c b/net/core/ethtool.c > index cd9bc67381b2..6ffcd8a602b8 100644 > --- a/net/core/ethtool.c > +++ b/net/core/ethtool.c > @@ -111,6 +111,7 @@ static const char netdev_features_strings[NETDEV_FEATURE_COUNT][ETH_GSTRING_LEN] > [NETIF_F_HW_TLS_RECORD_BIT] = "tls-hw-record", > [NETIF_F_HW_TLS_TX_BIT] = "tls-hw-tx-offload", > [NETIF_F_HW_TLS_RX_BIT] = "tls-hw-rx-offload", > + [NETIF_F_HW_PREEMPTION_BIT] = "tx-preemption", > }; > > static const char > -- > 2.17.1
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