Re: [dpdk-dev] [PATCH v2 3/3] eal/windows: librte_net build on Windows

[Fady Bader <fady@mellanox.com>]

> -----Original Message-----
> From: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
> Sent: Monday, July 20, 2020 7:27 PM
> To: Fady Bader <fady@mellanox.com>
> Cc: Narcisa Ana Maria Vasile <navasile@linux.microsoft.com>; dev@dpdk.org;
> Thomas Monjalon <thomas@monjalon.net>; Tasnim Bashar
> <tbashar@mellanox.com>; Tal Shnaiderman <talshn@mellanox.com>; Yohad Tor
> <yohadt@mellanox.com>; harini.ramakrishnan@microsoft.com;
> ocardona@microsoft.com; anand.rawat@intel.com; ranjit.menon@intel.com;
> olivier.matz@6wind.com
> Subject: Re: [dpdk-dev] [PATCH v2 3/3] eal/windows: librte_net build on
> Windows
> 
> On Mon, 20 Jul 2020 12:54:08 +0000, Fady Bader wrote:
> [snip]
> > > Getting the same error with a setup similar to Dmitry's. My setup:
> > > SDK 10.0.18362,
> >
> > I'm sending v4 patch that should resolve this.
> >
> > > clang 9.0.0. What version of clang are you using on your system?
> > > You can try installing LLVM 9.0.0 from
> > > https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fre
> > > leases.ll
> > >
> vm.org%2Fdownload.html&amp;data=02%7C01%7Cfady%40mellanox.com%7C0b
> > >
> 29fed755494b55361d08d82a9ff2b4%7Ca652971c7d2e4d9ba6a4d149256f461b%7C
> > > 0
> > >
> %7C0%7C637306213753996879&amp;sdata=5lPQtvt8EO7q8OAYN60J8rIdYdNJHjsS
> > > Pp%2B6P9PL3N0%3D&amp;reserved=0
> >
> > Thanks for the link, even with clang and SDK version same as yours and
> > Dmitry's I'm still passing compilation and not getting the error described.
> > That's because the _m_prefetchw function that is defined in Clang's
> > prfchwintrin.h is an intrinsic function corresponding to the
> > instruction PREFETCHW that is part of the instruction set extension
> > 3DNOW, my processor doesn't support this instruction set extension, so my
> compiler isn't reaching the part where it defines _m_prefetchw.
> > I think your processor does support the 3DNOW instruction set
> > extension and that why you are reaching this part and I'm not.
> 
> You can try building DPDK for a machine with RDSEED like so:
> 
> 	meson -Dmachine=broadwell -Dexamples=helloworld build

Even with this option I still don't get the error. With this option RDSEED is enabled
but the reason I'm not getting the error is that 3DNOW is not supported by my 
machine and its disabled.
Do you know of such way that I can enable instruction set extenuations for the 
project compilation?

> 
> FWIW, replacing <x86intrin.h> with <immintrin.h> in rte_random.c resolves the
> issue on my setup and also looks valid as per [1]. I checked LLVM 10.0.0, and both
> native and cross MinGW-w64 (GCC 9.2.0).
> 
> [1]:
> https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsoftware.
> intel.com%2Fsites%2Flandingpage%2FIntrinsicsGuide%2F%23text%3D_rdseed32
> _step%26expand%3D4541&amp;data=02%7C01%7Cfady%40mellanox.com%7Cd
> e059e4538474040e05e08d82cc9b058%7Ca652971c7d2e4d9ba6a4d149256f461b%7
> C0%7C0%7C637308592047834349&amp;sdata=5mzK66A1IF4n2KKhRSzbZxOYi0vhj
> D4AZlBWyW1oxD8%3D&amp;reserved=0

I also think this is a valid solution, this should be considered when adding the 
rte_random support for windows. As for now I didn't use rte_random in the V4 patch.