mlx4_SET_PORT_SCHEDULER(9)

💅 mlx4_SET_PORT_SCHEDULER — kernel API manual, bestie edition 💅

okay so this is a page from the Kernel API Manual, and honestly? it's a lil iconic. it's mlx4_SET_PORT_SCHEDULER(9), and we're about to make it make sense. 🎀

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✨ NAME ✨

mlx4_SET_PORT_SCHEDULER — this routine configures the arbitration between traffic classes (ETS) and configured rate limit for traffic classes. fr fr that's the whole job.

so here's the tea: tc_tx_bw, pg and ratelimit are arrays where each index represents a TC (traffic class, iykyk). and the description for those parameters below? yeah, it refers to a single TC. one at a time, one at a time. 💅

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🦋 SYNOPSIS 🦋

int mlx4_SET_PORT_SCHEDULER (struct mlx4_dev *dev , u8 port , u8
*tc_tx_bw , u8 *pg , u16 *ratelimit );

like yes, that's a lot of asterisks, but we're built different. ✨

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🎀 ARGUMENTS 🎀

• dev — an mlx4_dev. that's it, that's the whole description, and honestly sometimes that's enough. 🫶
• port — the physical port number.
• tc_tx_bw — the percentage of the bandwidth allocated for this traffic class within a TC group. and here's the important part, bestie, so pay attention: the sum of the bw_percentage of all the traffic classes within a TC group must equal 100% for correct operation. like, 100%. not 99, not 101. the math has to math. 🙈
• pg — the TC group that this traffic class is associated with.
• ratelimit — the maximal bandwidth allowed for use by this traffic class. yes, maximal. it's giving boundaries. 👑

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🧚 DESCRIPTION 🧚

returns 0 on success, or a negative mlx4_core errno code. so if you get a zero back, slay — that's your win. anything negative? that's an errno telling you what went sideways. 😭

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🌈 SEE ALSO 🌈

• Kernel file ./drivers/net/ethernet/mellanox/mlx4/fw_qos.h
• mlx4_SET_PORT_PRIO2TC(9)
• mlx4_ALLOCATE_VPP_get(9)
• mlx4_ALLOCATE_VPP_set(9)
• mlx4_SET_VPORT_QOS_get(9)
• mlx4_SET_VPORT_QOS_set(9)

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ok that's the whole page. no cap, you now know more about traffic class arbitration than like 90% of the group chat. icon behavior. 🦋💜

signed off from ./drivers/net/ethernet/mellano... — October 2026, in the mlx4_SET_PORT_SCHEDULER(9) era. mwah. 💋🎀✨