Date: Wed, 17 Sep 2025 07:21:18 +0000 From: bugzilla-noreply@freebsd.org To: net@FreeBSD.org Subject: [Bug 289333] [Feature Request] HFSC overhead calculation Message-ID: <bug-289333-7501-kFUg4J7Nqd@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-289333-7501@https.bugs.freebsd.org/bugzilla/> References: <bug-289333-7501@https.bugs.freebsd.org/bugzilla/>
next in thread | previous in thread | raw e-mail | index | archive | help
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D289333 --- Comment #6 from Daniel Engel <freebsd@danielengel.com> --- (In reply to Oleksandr Kryvulia from comment #5) I don't see a whole lot ofmuch potential in rate-limiting the number of packets. The mix of packet sizes never skews consistently in one direction= or the other. It varies by time of day and current user pattern(s). I will confess to not knowing much about ng_car and netgraph, but it appears to be mainly an API. It's not clear to me how writing a custom solution in user space is any significant improvement over writing a custom solution directly into the kernel.=20=20 So far, all I see are one-dimensional solutions to what is (at least) a 1.5 dimensional problem. The fact that Linux has a direct analog for the featu= re I am asking for implies to me that it can't be readily synthesized from some = set of lower-level features.=20=20 Based on my reading, it seems that HFSC already has almost all of the infrastructure to support a two-dimensional solution. Namely, the x and y coordinates for the service curve(s). It seems that every time that altq_hfsc.c calls m_pktlen(m) -- and there are only a small handful of such calls -- that it would be relatively easy to add a configurable parameter and/or helper function that simulates downstream overhead.=20=20 A couple of additional parameters could even allow HFSC to simulate the eff= ect of the 48-byte ATM boundaries and encoding, although the conventional 15% derating in line throughput probably remains an adequate approximation. --=20 You are receiving this mail because: You are the assignee for the bug.=
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?bug-289333-7501-kFUg4J7Nqd>