Date: Tue, 23 Sep 2014 19:18:51 -0400 From: Ryan Stone <rysto32@gmail.com> To: freebsd-net <freebsd-net@freebsd.org> Subject: [PATCH] Convert ixl(4) and ixlv(4) to ifcounters, and fix some counter bugs Message-ID: <CAFMmRNyn0Kjr30Ew%2B8YRRvT-tMFH6WdprAAyJieLz_ABDNK8%2BA@mail.gmail.com>
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The patch below converts the ixl(4) and ixlv(4) drivers to use the new ifcounter interface. I've hidden the interface behind some macros to ensure that the driver continues to compile for FreeBSD 10 and earlier. The result of the macros is that the ifcounter implementation is somewhat clunkier than I would have liked, but I preferred to try and share as much code between the legacy counter implementation and the ifcounter implementation. I have tested the ixl driver with head. I have only compile-tested it for stable/10. This patch also fixes some counter bugs: - Ensure that tx discards are reported - There are actually two types of rx discard counters in the hardware. Currently the driver is only reporting discards from one of the two counters, so I fixed that - The ipackets and opackets counters were being unnecessarily incremented in the rx and tx paths. This was racy, unnecessary (the counters also get explicitly set based on the values in HW counters) and very bad for performance -- the cacheline contained the counters was constantly bouncing between CPUs. I saw this even with only one queue active, probably due to false sharing with some other field in the ifnet struct. https://people.freebsd.org/~rstone/patches/ixl/0005-Convert-ixl-and-ixlv-drivers-to-use-new-ifcounter-in.patch
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