Build Options for maximum performance of SHA256

[opensslmailing]

>> Date: Mon, 5 Feb 2024 09:48:21 +0100
>> From: opensslmailing <mailto:opensslmailing at gmx.de>
>> To: mailto:openssl-users at openssl.org
>> Subject: Build Options for maximum performance of SHA256 digest
>>       calculation
>> Message-ID: <mailto:76163372.20240205094821 at gmx.de>
>> Content-Type: text/plain; charset=us-ascii

>> I want to build openssl for Windows to achieve best possible performance on
>> my machine (Core i5 6500) of SHA256 digest calculation for large files in a
>> C++ program. What options do I have to use to achieve this?

>> P.S. Currently my program calculates about 330 Mibyte/s whereas other programs
>> using OpenSSL reach about 400 MiByte/s on the same machine with the same file

> I don't think this is really on-topic for this list, but some suggestions for
> things to investigate:
> - How big is the file?
> - How are you reading the file (istream, fopen as text, fopen as binary, read,
>   memory map)?
> - How are the other programs reading it?
> - What platform are you running on? What compiler are you using?
> - When you build OpenSSL, are you specifying compiler flags to generate code for
>   modern processors only?


> Martin Bonner

Hello,

 - the file is 4 GiByte of size
 -  I'm  reading  the  file using OpenSSL BIO mechanism with the "rb"
 option, so read as binary
 -  I  don't  know  how the other program (btw. it is fchash from the
 FastCopy program) reads the file
 -  The  platform is Windows 10 64 Bit. The compiler is Visual Studio
 2022
 - I'm using the following line:
perl Configure VC-WIN64A --prefix=<respectivedirectory> --openssldir=<respectivedirectory> no-shared



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