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From: "Cohen, Eugene" <eugene@hp.com>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: "edk2-devel@lists.01.org" <edk2-devel@lists.01.org>,
	"leif.lindholm@linaro.org" <leif.lindholm@linaro.org>,
	"liming.gao@intel.com" <liming.gao@intel.com>
Subject: Re: [PATCH 1/3] ArmPkg/CompilerIntrinsicsLib: replace memcpy and memset with C code
Date: Thu, 11 Aug 2016 21:50:20 +0000	[thread overview]
Message-ID: <AT5PR84MB029157C951664077DEE207ABB41E0@AT5PR84MB0291.NAMPRD84.PROD.OUTLOOK.COM> (raw)
In-Reply-To: <CAKv+Gu82Nx7MT7nkw2yTBMt67BBDOD=pqmOjw-eiNwb25zk3iQ@mail.gmail.com>

> > Why does memcpy performance matter?  In addition to the overall
> memcpy stuff scattered around C code we have an instance that is
> particularly sensitive to memcpy performance.  For DMA operations
> when invoking double-buffering or access to portions of a buffer that
> is common mapped (i.e. uncached on non-coherent DMA systems) the
> impact of a non-optimized memcpy is enormous compared to the
> optimized ones because the penalty is amplified by orders of
> magnitude due to uncached memory access latency.
> >
> 
> That code would be using CopyMem(), no? This only serves the
> compiler
> generated calls, which are few since Tianocore does not allow
> initialized locals.

I see and agree that should minimize the impact.   I guess I'll ask the naive question.  Could the BaseMemoryLib and CompilerIntrinsicsLib share the same stuff?


  reply	other threads:[~2016-08-11 21:50 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-11 18:20 [PATCH 1/3] ArmPkg/CompilerIntrinsicsLib: replace memcpy and memset with C code Ard Biesheuvel
2016-08-11 18:20 ` [PATCH 2/3] BaseTools RVCT: ignore various RVC diagnostics Ard Biesheuvel
2016-08-12  3:04   ` Gao, Liming
2016-08-11 18:20 ` [PATCH 3/3] MdePkg RVCT: add definition of UNREACHABLE Ard Biesheuvel
2016-08-12  3:04   ` Gao, Liming
2016-08-11 21:34 ` [PATCH 1/3] ArmPkg/CompilerIntrinsicsLib: replace memcpy and memset with C code Cohen, Eugene
2016-08-11 21:45   ` Ard Biesheuvel
2016-08-11 21:50     ` Cohen, Eugene [this message]
2016-08-11 21:53       ` Ard Biesheuvel
2016-08-11 23:04       ` Andrew Fish
2016-08-12  8:09         ` Ard Biesheuvel
2016-09-01 13:11 ` Leif Lindholm

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