Date: Tue, 18 Dec 2018 09:40:22 +0100 From: Gary Jennejohn <gljennjohn@gmail.com> To: Andrew Gallatin <gallatin@cs.duke.edu> Cc: Bruce Evans <brde@optusnet.com.au>, svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, Slava Shwartsman <slavash@freebsd.org> Subject: Re: svn commit: r341578 - head/sys/dev/mlx5/mlx5_en Message-ID: <20181218094022.0deab2fa@ernst.home> In-Reply-To: <b81d9232-d703-2d4f-eec2-f9b48a0ccd3b@cs.duke.edu> References: <201812051420.wB5EKwxr099242@repo.freebsd.org> <9e09a2f8-d9fd-7fde-8e5a-b7c566cdb6a9@cs.duke.edu> <20181218033137.Q2217@besplex.bde.org> <b81d9232-d703-2d4f-eec2-f9b48a0ccd3b@cs.duke.edu>
next in thread | previous in thread | raw e-mail | index | archive | help
On Mon, 17 Dec 2018 14:50:04 -0500 Andrew Gallatin <gallatin@cs.duke.edu> wrote: > On 12/17/18 2:08 PM, Bruce Evans wrote: [snip] > > iflib uses queuing techniques to significantly pessimize em NICs with 1 > > hardware queue. On fast machines, it attempts to do 1 context switch per > > This can happen even w/o contention when "abdicate" is enabled in mp > ring. I complained about this as well, and the default was changed in > mp ring to not always "abdicate" (eg, switch to the tq to handle the > packet). Abdication substantially pessimizes Netflix style web > uncontended workloads, but it generally helps small packet forwarding. > > It is interesting that you see the opposite. I should try benchmarking > with just a single ring. > Why are iflib and ifdi compiled into EVERY kernel with device ether and/or device pci when only a few NICs actually use iflib? This is really unnecessary bloat in an already bloated kernel. I use if_re which does not use iflib. I removed iflib and ifdi from /sys/conf/files and my network still works just fine. It seems to me like these iflib entries need finer-grained options, e.g. one of the NICs which use iflib is enabled, before pulling them into the kernel build. -- Gary Jennejohn
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20181218094022.0deab2fa>