openssl performance delta built-in vs custom compiled

Frank Rehberger Frank.Rehberger at
Sun Jan 25 19:18:20 UTC 2015


It might be an issue with cache lines,  using shared libs memory layout
might fit better to your processor-caches

Would be interesting to verify performance on different architecture.

Regards, Frank

On 25.01.2015 12:44, Marcus Pollice wrote:
> Marcus Pollice
> On 22.12.2014 03:20, Mathieu Trudel-Lapierre wrote:
>> I don't think there would be very many patches that are meant to improve
>> performance in our patch set (note, I did not check).
> That was a good assumption. Although some patches looked suspicious I
> ultimately found that these patches don't materially affect performance.
> More about that below.
>> You may also which to check what are all
>> the compiler options coming from dpkg-buildflags used in the build...
> That was a good idea indeed, but there was nothing out of the order
> coming from there. Also since openssl writes the compile options to the
> console when running the benchmarks I could test most of these before to
> have no real effect.
>> I would suggest using the source package as a base
>> and using debuild / chroots / PPAs to build your custom package, that
>> way you'd benefit from the same performance unless your custom changes
>> impact them in some way, with the least amount of effort.
> Ultimately I used the Debian way of building to reproduce the same
> performance level as the built-in packages. Then I started playing with
> doing certain steps of the compilation manually vs automated building.
> When I got a build with the patches applied and the same low performance
> I was getting before I knew it was not the patches. I then dissected the
> buildlog and at some point I noticed the major difference is that the
> built-in version will be compiled with shared libraries.
> This is indeed the root cause for the performance difference I found.
> The versions using shared libraries are indeed faster than a static
> build (at least for the small data sizes). This is completely unexpected
> to me. It is also somewhat unsatisfying as I now know the cause but
> don't quite understand it.

Best regards - Mit freundlichen Grüßen - 谨致问候
Frank Rehberger, Berlin, Germany
Phone: +49-173-205-7118
Frank.Rehberger at

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