Skip site navigation (1)Skip section navigation (2)
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>

next in thread | previous in thread | raw e-mail | index | archive | help
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



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAG6CVpXEo_v1gPd7YVfQxHJOccuDQ2-xmLTHKvMs9RL=04zrmA>