tcp_lp_owd_calculator(9)

🧚 tcp_lp_owd_calculator(9) 🧚

Okay bestie, this one is from the Kernel API Manual, and it’s a tiny little kernel function page. We’re gonna read it together, no cap. 💖

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🌸 NAME 🌸

tcp_lp_owd_calculator — that’s the function name, and the original NAME line is literally just that name plus a bare - with no description after it. Iconic minimalism, honestly. 💅

✨ SYNOPSIS ✨

The signature is exactly this, copied with love:

u32 tcp_lp_owd_calculator (struct sock *sk );

So yeah, it returns a u32, and it takes a struct sock *sk. Slay. 🎀

🦋 ARGUMENTS 🦋

• sk — the socket we’re calculating the one way delay for, bestie. That’s the whole argument vibe. 🌸

💜 DESCRIPTION 💜

This function calculates the one way delay, aka OWD, in relative format. Periodt. ✨

Now the lore: the original implementation did OWD as minus of the remote time difference to the local time difference, directly. Because this time difference is just simply equal to RTT, when the network status is stable, the remote RTT will equal the local RTT, and the resulting OWD goes into zero. 😭

That seems to be a bug, and so we fixed it. No cap, that’s the whole story. 💀

🌈 SEE ALSO 🌈

• Kernel file ./net/ipv4/tcp_lp.c
• enum tcp_lp_state(9)
• struct lp(9)
• tcp_lp_init(9)
• tcp_lp_cong_avoid(9)
• tcp_lp_remote_hz_estimator(9)
• tcp_lp_rtt_sample(9)
• tcp_lp_pkts_acked(9)

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byeee 🫶 — sourced from ./net/ipv4, dated October 2026.