TC(8)

💖 TC(8) ✨ choke 💖

✨ NAME ✨

okay so the manual name here is choke, and it's a choose and keep scheduler 🎀

🧚 SYNOPSIS 🧚

tc qdisc ... choke limit packets min packets max packets avpkt bytes
burst packets [ ecn ] [ bandwidth rate ] probability chance

🌸 DESCRIPTION 🌸

bestie, you have to know about CHOKe 😭 It stands for CHOose and Keep for responsive flows, CHOose and Kill for unresponsive flows, and it's a classless qdisc that's built to spot and punish any flow hogging the queue. It's basically a variation of RED, so if you already know RED, the setup will feel super familiar 🦋

💅 ALGORITHM 💅

Here's the tea ☕ Once the queue hits a certain average length, the scheduler grabs a random packet from the queue.

• If the packet that's about to join the queue and the packet it grabbed belong to the same flow, both get dropped 💀
• Otherwise, if the queue length is still below the maximum length, the new packet has a configurable chance of getting marked (which can mean dropped too) 🫶
• If the queue length goes over max, the new packet is always marked (or dropped) 😭
• If the queue length goes over limit, the new packet is always dropped 🙈

The marking probability math is the exact same as what the RED qdisc uses, so no new brain cells needed 🧠✨

🎀 PARAMETERS 🎀

The parameters are the same as RED's, with one lowkey big difference: RED counts bytes, but choke counts packets 🍓 For the full rundown, check out tc-red(8) 💜

🌈 SOURCE 🌈

These are the papers the whole thing is based on, so you can read them if you're obsessed like me 📚

• R. Pan, B. Prabhakar, and K. Psounis, "CHOKe, A Stateless Active Queue Management Scheme for Approximating Fair Bandwidth Allocation", IEEE INFOCOM, 2000. 🦋
• A. Tang, J. Wang, S. Low, "Understanding CHOKe: Throughput and Spatial Characteristics", IEEE/ACM Transactions on Networking, 2004 🌟

🔥 SEE ALSO 🔥

tc(8), tc-red(8) — go check these out next, they're iconic 👑

🦋 AUTHOR 🦋

sched_choke was contributed by Stephen Hemminger 🫶

Okay bestie, that's the whole page! 💖 It came from iproute2, dated August 2011, under the TC(8) label on Linux ✨ Slay the queue and stay hydrated 💅🌸