From 49f5b769d5bd203596b0db4df72344f20f59e938 Mon Sep 17 00:00:00 2001 From: Amit Cohen Date: Thu, 19 Jan 2023 11:32:32 +0100 Subject: [PATCH] mlxsw: Add support of latency TLV The latency of each EMAD can be measured by firmware. The driver can get the measurement via latency TLV which can be added to each EMAD. This TLV is optional, when EMAD is sent with this TLV, the EMAD's response will include the TLV and the field 'latency_time' will contain the firmware measurement. This information can be processed using BPF program for example, to create a histogram and average of the latency per register. In addition, it is possible to measure the end-to-end latency, and then reduce firmware measurement, which will result in the latency of the software overhead. This information can be useful to improve the driver performance. Add support for latency TLV by default for all EMADs. First we planned to enable latency TLV per demand, using devlink-param. After some tests, we know that the usage of latency TLV does not impact the end-to-end latency, so it is OK to enable it by default. Note that similar to string TLV, the latency TLV is not supported in all firmware versions. Enable the usage of this TLV only after verifying it is supported by the current firmware version by querying the Management General Information Register (MGIR). Signed-off-by: Danielle Ratson Signed-off-by: Amit Cohen Reviewed-by: Ido Schimmel Signed-off-by: Petr Machata Reviewed-by: Tony Nguyen Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/mellanox/mlxsw/core.c | 35 +++++++++++++++++++++++++++++- 1 file changed, 34 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/mellanox/mlxsw/core.c b/drivers/net/ethernet/mellanox/mlxsw/core.c index a51d413..f952a65 100644 --- a/drivers/net/ethernet/mellanox/mlxsw/core.c +++ b/drivers/net/ethernet/mellanox/mlxsw/core.c @@ -78,6 +78,7 @@ struct mlxsw_core { spinlock_t trans_list_lock; /* protects trans_list writes */ bool use_emad; bool enable_string_tlv; + bool enable_latency_tlv; } emad; struct { u16 *mapping; /* lag_id+port_index to local_port mapping */ @@ -477,6 +478,12 @@ static void mlxsw_emad_pack_op_tlv(char *op_tlv, mlxsw_emad_op_tlv_tid_set(op_tlv, tid); } +static void mlxsw_emad_pack_latency_tlv(char *latency_tlv) +{ + mlxsw_emad_latency_tlv_type_set(latency_tlv, MLXSW_EMAD_TLV_TYPE_LATENCY); + mlxsw_emad_latency_tlv_len_set(latency_tlv, MLXSW_EMAD_LATENCY_TLV_LEN); +} + static int mlxsw_emad_construct_eth_hdr(struct sk_buff *skb) { char *eth_hdr = skb_push(skb, MLXSW_EMAD_ETH_HDR_LEN); @@ -506,6 +513,11 @@ static void mlxsw_emad_construct(const struct mlxsw_core *mlxsw_core, buf = skb_push(skb, reg->len + sizeof(u32)); mlxsw_emad_pack_reg_tlv(buf, reg, payload); + if (mlxsw_core->emad.enable_latency_tlv) { + buf = skb_push(skb, MLXSW_EMAD_LATENCY_TLV_LEN * sizeof(u32)); + mlxsw_emad_pack_latency_tlv(buf); + } + if (mlxsw_core->emad.enable_string_tlv) { buf = skb_push(skb, MLXSW_EMAD_STRING_TLV_LEN * sizeof(u32)); mlxsw_emad_pack_string_tlv(buf); @@ -520,6 +532,7 @@ static void mlxsw_emad_construct(const struct mlxsw_core *mlxsw_core, struct mlxsw_emad_tlv_offsets { u16 op_tlv; u16 string_tlv; + u16 latency_tlv; u16 reg_tlv; }; @@ -530,6 +543,13 @@ static bool mlxsw_emad_tlv_is_string_tlv(const char *tlv) return tlv_type == MLXSW_EMAD_TLV_TYPE_STRING; } +static bool mlxsw_emad_tlv_is_latency_tlv(const char *tlv) +{ + u8 tlv_type = mlxsw_emad_latency_tlv_type_get(tlv); + + return tlv_type == MLXSW_EMAD_TLV_TYPE_LATENCY; +} + static void mlxsw_emad_tlv_parse(struct sk_buff *skb) { struct mlxsw_emad_tlv_offsets *offsets = @@ -537,6 +557,8 @@ static void mlxsw_emad_tlv_parse(struct sk_buff *skb) offsets->op_tlv = MLXSW_EMAD_ETH_HDR_LEN; offsets->string_tlv = 0; + offsets->latency_tlv = 0; + offsets->reg_tlv = MLXSW_EMAD_ETH_HDR_LEN + MLXSW_EMAD_OP_TLV_LEN * sizeof(u32); @@ -545,6 +567,11 @@ static void mlxsw_emad_tlv_parse(struct sk_buff *skb) offsets->string_tlv = offsets->reg_tlv; offsets->reg_tlv += MLXSW_EMAD_STRING_TLV_LEN * sizeof(u32); } + + if (mlxsw_emad_tlv_is_latency_tlv(skb->data + offsets->reg_tlv)) { + offsets->latency_tlv = offsets->reg_tlv; + offsets->reg_tlv += MLXSW_EMAD_LATENCY_TLV_LEN * sizeof(u32); + } } static char *mlxsw_emad_op_tlv(const struct sk_buff *skb) @@ -813,7 +840,7 @@ static const struct mlxsw_listener mlxsw_emad_rx_listener = static int mlxsw_emad_tlv_enable(struct mlxsw_core *mlxsw_core) { char mgir_pl[MLXSW_REG_MGIR_LEN]; - bool string_tlv; + bool string_tlv, latency_tlv; int err; mlxsw_reg_mgir_pack(mgir_pl); @@ -824,11 +851,15 @@ static int mlxsw_emad_tlv_enable(struct mlxsw_core *mlxsw_core) string_tlv = mlxsw_reg_mgir_fw_info_string_tlv_get(mgir_pl); mlxsw_core->emad.enable_string_tlv = string_tlv; + latency_tlv = mlxsw_reg_mgir_fw_info_latency_tlv_get(mgir_pl); + mlxsw_core->emad.enable_latency_tlv = latency_tlv; + return 0; } static void mlxsw_emad_tlv_disable(struct mlxsw_core *mlxsw_core) { + mlxsw_core->emad.enable_latency_tlv = false; mlxsw_core->emad.enable_string_tlv = false; } @@ -902,6 +933,8 @@ static struct sk_buff *mlxsw_emad_alloc(const struct mlxsw_core *mlxsw_core, sizeof(u32) + mlxsw_core->driver->txhdr_len); if (mlxsw_core->emad.enable_string_tlv) emad_len += MLXSW_EMAD_STRING_TLV_LEN * sizeof(u32); + if (mlxsw_core->emad.enable_latency_tlv) + emad_len += MLXSW_EMAD_LATENCY_TLV_LEN * sizeof(u32); if (emad_len > MLXSW_EMAD_MAX_FRAME_LEN) return NULL; -- 2.7.4