Date: Fri, 27 May 2016 13:58:31 -0700 From: Conrad Meyer <cem@FreeBSD.org> To: "Ngie Cooper (yaneurabeya)" <yaneurabeya@gmail.com> Cc: Garrett Cooper <ngie@freebsd.org>, src-committers <src-committers@freebsd.org>, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r300868 - head/tools/tools/ioat Message-ID: <CAG6CVpXEo_v1gPd7YVfQxHJOccuDQ2-xmLTHKvMs9RL=04zrmA@mail.gmail.com> In-Reply-To: <2F93033E-D202-4A0A-8555-76ED789D4080@gmail.com> References: <201605272012.u4RKCWCI035708@repo.freebsd.org> <CAG6CVpUt425z_YyTb7E7TGDkTuZFpGDjz6N3JRg3Ksq6K6-ZuQ@mail.gmail.com> <2F93033E-D202-4A0A-8555-76ED789D4080@gmail.com>
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I don't think such infrastructure is needed for simple test code like this. 128 is more than enough. On Fri, May 27, 2016 at 1:51 PM, Ngie Cooper (yaneurabeya) <yaneurabeya@gmail.com> wrote: > >> On May 27, 2016, at 13:34, Conrad Meyer <cem@FreeBSD.org> wrote: >> >> On Fri, May 27, 2016 at 1:12 PM, Garrett Cooper <ngie@freebsd.org> wrote= : >>> Author: ngie >>> Date: Fri May 27 20:12:32 2016 >>> New Revision: 300868 >>> URL: https://svnweb.freebsd.org/changeset/base/300868 >>> >>> Log: >>> Remove note about bogus chain-len maximum >>> >>> There's no current limit on chain-len with Broadwell DE chips; it isn'= t >>> enforced in software, and there doesn't appear to be a hardware limita= tion >>> either on the Intel Xeon D-1527 (Broadwell-DE) chip. >> >> Hi Ngie, >> >> The note isn't bogus, it's just not what you think it is=E2=80=94the lim= it is >> in the ioat_test code, not a limit of the hardware. >> >> Before this commit which documented it (r289733), the limit *was* 4. >> However, in the same commit I bumped the limit up to 128 >> (IOAT_MAX_BUFS / 2). (I suspect I wrote the documentation first, >> before deciding to raise the limit.) >> >> So the current limit is 128, and should be documented. > > Ah=E2=80=A6 that makes sense. Would it be a better idea to make this limi= t into a readonly sysctl in ioat_test(4), along with the other limits? If s= o, I=E2=80=99ll put that out for CR. > Thanks, > -Ngie
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