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Date:      Fri, 29 Aug 2014 11:13:52 -0700
From:      Jack Vogel <jfvogel@gmail.com>
To:        Konstantin Belousov <kostikbel@gmail.com>
Cc:        "svn-src-head@freebsd.org" <svn-src-head@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "Bjoern A. Zeeb" <bz@freebsd.org>, "src-committers@freebsd.org" <src-committers@freebsd.org>
Subject:   Re: svn commit: r270806 - head/sys/dev/ixl
Message-ID:  <CAFOYbcmpiGcO59LFC0LsSmqLmaf_VGeiTfALjgLJA2niokrzHQ@mail.gmail.com>
In-Reply-To: <CAFOYbcmgcJh6aVKiFDjNRPo%2B9q0HiTbWKc6HpD1h%2BuB8-G0ahg@mail.gmail.com>
References:  <201408291240.s7TCe1OQ029986@svn.freebsd.org> <20140829171452.GO2737@kib.kiev.ua> <CAFOYbcmgcJh6aVKiFDjNRPo%2B9q0HiTbWKc6HpD1h%2BuB8-G0ahg@mail.gmail.com>

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OH, and I just asked the team here, and found out we explicitly do NOT
support any 32 bit environment for this driver.

Jack



On Fri, Aug 29, 2014 at 10:49 AM, Jack Vogel <jfvogel@gmail.com> wrote:

> I certainly agree that it would be a bit ridiculous to do 40G in a 32bit
> environment :)
>
> Jack
>
>
>
> On Fri, Aug 29, 2014 at 10:14 AM, Konstantin Belousov <kostikbel@gmail.com
> > wrote:
>
>> On Fri, Aug 29, 2014 at 12:40:01PM +0000, Bjoern A. Zeeb wrote:
>> > Author: bz
>> > Date: Fri Aug 29 12:40:01 2014
>> > New Revision: 270806
>> > URL: http://svnweb.freebsd.org/changeset/base/270806
>> >
>> > Log:
>> >   Properly handle prefetch only for amd64 and i386 as we do elsewhere.
>> >
>> >   In general theraven is right that we should factr this out and provide
>> >   a general and per-arch implementation that everything can use.
>> >
>> >   MFC after:  3 days
>> >   X-MFC with: r270755
>> >
>> > Modified:
>> >   head/sys/dev/ixl/i40e_osdep.h
>> >
>> > Modified: head/sys/dev/ixl/i40e_osdep.h
>> >
>> ==============================================================================
>> > --- head/sys/dev/ixl/i40e_osdep.h     Fri Aug 29 11:18:54 2014
>> (r270805)
>> > +++ head/sys/dev/ixl/i40e_osdep.h     Fri Aug 29 12:40:01 2014
>> (r270806)
>> > @@ -137,11 +137,15 @@ struct i40e_spinlock {
>> >
>> >  #define le16_to_cpu
>> >
>> > +#if defined(__amd64__) || defined(i386)
>> >  static __inline
>> >  void prefetch(void *x)
>> >  {
>> >       __asm volatile("prefetcht0 %0" :: "m" (*(unsigned long *)x));
>> >  }
>> This only fix the build failure, but the code is still somewhat wrong.
>>
>> Availability of the prefetch instruction depends on the presence of SSE.
>> Althought it is probably impossible to find a machine where the intended
>> hardware can operate and which does not support SSE _currently_, I am
>> not sure that it is wise to hard-code SSE instructions in the i386
>> kernel.
>>
>> Might be, a change of the compilation test from both amd64 and i386 to
>> just amd64 is due.  I doubt that anybody would use 40Gb with 32bit OS,
>> and even if somebody does, that the performace is at the stake in
>> this case.
>>
>> > +#else
>> > +#define      prefetch(x)
>> > +#endif
>> >
>> >  struct i40e_osdep
>> >  {
>>
>
>



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