Date: Fri, 26 Sep 2014 15:25:59 -0700 From: Eric Joyner <ricera10@gmail.com> To: Gleb Smirnoff <glebius@freebsd.org> Cc: freebsd-net <freebsd-net@freebsd.org>, Ryan Stone <rysto32@gmail.com> Subject: Re: [PATCH] Convert ixl(4) and ixlv(4) to ifcounters, and fix some counter bugs Message-ID: <CA%2Bb0zg-oN2CH-XRSNTm6O7O67BSHdscfC1ntLaZUeXi448S9xA@mail.gmail.com> In-Reply-To: <20140925120810.GA884@FreeBSD.org> References: <CAFMmRNyn0Kjr30Ew%2B8YRRvT-tMFH6WdprAAyJieLz_ABDNK8%2BA@mail.gmail.com> <20140925120810.GA884@FreeBSD.org>
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I approve of this patch -- I tested it on ixl and ixlv on stable/10, and at least the sysctl stats still look good. --- - Eric Joyner On Thu, Sep 25, 2014 at 5:08 AM, Gleb Smirnoff <glebius@freebsd.org> wrote: > On Tue, Sep 23, 2014 at 07:18:51PM -0400, Ryan Stone wrote: > R> The patch below converts the ixl(4) and ixlv(4) drivers to use the new > R> ifcounter interface. I've hidden the interface behind some macros to > R> ensure that the driver continues to compile for FreeBSD 10 and > R> earlier. The result of the macros is that the ifcounter > R> implementation is somewhat clunkier than I would have liked, but I > R> preferred to try and share as much code between the legacy counter > R> implementation and the ifcounter implementation. > R> > R> I have tested the ixl driver with head. I have only compile-tested it > R> for stable/10. > R> > R> This patch also fixes some counter bugs: > R> > R> - Ensure that tx discards are reported > R> - There are actually two types of rx discard counters in the hardware. > R> Currently the driver is only reporting discards from one of the two > R> counters, so I fixed that > R> - The ipackets and opackets counters were being unnecessarily > R> incremented in the rx and tx paths. This was racy, unnecessary (the > R> counters also get explicitly set based on the values in HW counters) > R> and very bad for performance -- the cacheline contained the counters > R> was constantly bouncing between CPUs. I saw this even with only one > R> queue active, probably due to false sharing with some other field in > R> the ifnet struct. > R> > R> > https://people.freebsd.org/~rstone/patches/ixl/0005-Convert-ixl-and-ixlv-drivers-to-use-new-ifcounter-in.patch > > Thanks, Ryan! > > I'd suggest to use check against __FreeBSD_version >= 1100036. > > Can you please commit this? Navdeep promised to do cxgbe(4), Alexander > is working on ixgbe. After that we can go forward with making counters > in struct ifnet non-racy and cheap counter(9). > > -- > Totus tuus, Glebius. > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" >
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