libeth_xdp_queue_threshold(9)

✨ libeth_xdp_queue_threshold 💅

okay so bestie, you know libeth_xdp_queue_threshold from the Kernel API Manual? we're gonna get into it, because this little function is lowkey the math bestie that keeps your queues from vibing off a cliff 🫶

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🌸 NAME 🌸

libeth_xdp_queue_threshold — calculate XDP queue clean/refill threshold ✨

like, it literally computes the threshold, that's the whole job 💖

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🦋 SYNOPSIS 🦋

u32 libeth_xdp_queue_threshold (u32 count );

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🎀 ARGUMENTS 🎀

• count — number of descriptors in the queue. that's it, that's the input 🍓

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💜 DESCRIPTION 💜

so here's the tea ☕: the threshold is the limit where two things kick off:

• RQs start to refill — this happens when the number of empty buffers exceeds the threshold 🔥
• SQs get cleaned up — this happens when the number of free descriptors goes below the threshold 🧹

to speed up hotpath processing, the threshold is always pow-2, and it's closest to 1/4 of the queue length. iconic behavior honestly 👑

⚠️ bestie do NOT call it on hotpath ⚠️ — calculate it and cache the threshold during the queue initialization instead. no cap, this one matters 😭

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🌈 RETURN 🌈

the calculated threshold. that's the whole return value, slay 💅

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🧚 SEE ALSO 🧚

• Kernel file ./drivers/net/ethernet/intel/libeth/xdp.c 📁
• libeth_xdpsq_init_timer(9)
• libeth_xdp_tx_exception(9)
• libeth_xdp_load_stash(9)
• libeth_xdp_save_stash(9)
• libeth_xdp_return_buff_slow(9)
• libeth_xdp_buff_add_frag(9)
• libeth_xdp_prog_exception(9)
• libeth_xdp_return_buff_bulk(9)
• __libeth_xdp_set_features(9)
• libeth_xdp_set_redirect(9)

the whole squad, fr fr 🫶

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okay that's the whole page bestie, we ate and left zero crumbs 💖 this cutie comes from ./drivers/net/ethernet/intel/l... and it's dated October 2026, so mark your calendar and go calculate that threshold at init time like the main character you are ✨🎀🦋