Date: Sat, 02 Dec 2017 05:11:20 +0000 From: "K. Macy" <kmacy@freebsd.org> To: Joe Buehler <aspam@cox.net> Cc: "freebsd-net@freebsd.org" <freebsd-net@freebsd.org> Subject: Re: netmap / LINUX realtime / ixgbevf: huge RX latencies Message-ID: <CAHM0Q_NEr-VfbhKT2Fth4ou2eiwJBBE5MRNy84K2eypDt98%2BzA@mail.gmail.com> In-Reply-To: <5A206FB9.3010106@cox.net> References: <5A206FB9.3010106@cox.net>
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HEAD or 11? On Thu, Nov 30, 2017 at 13:03 Joe Buehler <aspam@cox.net> wrote: > I am using the LINUX 4.4.86 realtime kernel patch with netmap and the > ixgbevf driver (SRIOV in a VM) and having some serious RX latency issues. > > The ixbgevf driver built by the netmap build against the kernel source > does not work. I haven't tried to debug it -- the netmap driver > complains about bad ring index values and resets (over and over again as > my app runs). > > The non-netmap version of ixgbevf that comes with the kernel works but > appears to have serious RX latency issues due to frame batching. It > appears that the kernel's NAPI polling reads frames from the NIC, then > netmap processes the frames, then epoll exits and my app can work on the > frames. The delay between start of NAPI to my app getting frames can be > milliseconds!!! > > Would the netmap-modified ixgbevf driver eliminate this latency? > > If so, any ideas on what might be going wrong with the modified driver? > Perhaps an older version of the driver might be better? The kernel > ixgbevf version is 2.12.1-k while netmap is trying to use 4.2.1. > Looking at the RT patch for LINUX there are only a few network driver > patches, none for the ixgbe* cards. > > Joe Buehler > > _______________________________________________ > freebsd-net@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" >
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