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From "Kees Spoelstra" <>
Subject RE: Openssl 1.1.0f Support
Date Thu, 21 Sep 2017 14:32:33 GMT


Looking at the presentation it seems that the openssl async jobs approach was not tested,
but planned. Dave mentioned static code analysis and no performance tests.


Within openssl+QAT you get the performance from running the openssl calls in an async job
which becomes a sort of coroutine, which is then run in openssl’s threadpool. When offloading,
it yields control to the scheduler, freeing the CPU for other jobs. Ofcourse it is a bit harder
than this :)

Building the jobs could be easy, the whole song and dance around synchronization, thread alignment,
could be too cumbersome to bother with.


Next to that it seems that the async jobs are a bit slower when only using the CPU, so you
would end up with two separate flows to ensure the same performance for 99.99% of the users.


Anybody willing to donate an Intel QAT PCI card :) Our address is ….


Note: It seems that the intel QAT cards have an unexpected scaling problem with ECDHE-RSA,
which they (intel) were looking into, and with the >32 thread CPUs you will get a break
even situation. So for HTTP/2 the benefit would be much smaller than normal RSA if the machine
has enough cores. Ofcourse the Intel QAT card should still offload the CPU.







From: Alan Carroll [] 
Sent: Thursday, September 21, 2017 15:13
Subject: Re: Openssl 1.1.0f Support


Kees - I think Dave and/or Susan tried the thread off loading approach. I think it is mentioned
in the presentation cited above. IIRC that ended up not working well for some reason.


On Thu, Sep 21, 2017 at 2:49 AM, Kees Spoelstra < <>
> wrote:

Hi Dave and Jeremy, 


We were also looking into using Intel QAT, the AES was not of interest to us , mostly improving
the RSA handshake phase.


Not having looked at the API, I wonder if we would able to offload the handshake part to threads
which handle the openssl-async stuff, and after the handshake go back to normal processing.
 Performance of SSL handshakes is bound by raw CPU and pretty low in rq/s, so the overhead
in thread sync could be negligible.  Any thoughts about that?


We’re pretty busy here, but I’m going to check here if we can burn some cycles on looking
into this. Any other insights from the tests at yahoo are welcome.




From: Dave Thompson [ <> ] 
Sent: Wednesday, September 20, 2017 23:17
To: <> 
Subject: Re: Openssl 1.1.0f Support


Sorry Jeremy, my recollections were from 16 months ago which is fuzzy by now at best.   The
gist of my recollection is that QAT is an IO based async engine, which of course ATS already
has done extensively.   I recall the under-the-hood QAT longjumping was a non-starter in an
ATS framework.   This was all static code analysis.  Integration looked like a non-starter,
so no performance test done.

Regarding performance testing of "ATS + Openssl 1.1.0(x) + standard aes-ni acceleration",
Susan (?Bryan?) was just telling me today of a measured order of magnitude improvement over
with the same using Openssl 1.0.1(x) and small packet sizes...  Improvement attributed to
lock contention issues in the older OpenSSL 1.0.1(x).



On Wed, Sep 20, 2017 at 3:22 PM, Jeremy Payne < <>
> wrote:


Did you run any comparison performance tests using the QAT engine ?
Specifically around these configurations(or similar)

1. ATS + Openssl 1.1.0(x) + QAT engine(sync)
2. ATS + Openssl 1.1.0(x) + standard aes-ni acceleration

On Wed, Sep 20, 2017 at 11:26 AM, Dave Thompson < <>
> wrote:
> July 2016, I was evaluating the async Quick Assist in the context of ATS,
> and came away with the opinion it's value comes into play with a much
> simpler application.   It's effectively it's own async engine, long jumping
> across the stack, and doesn't play well or add  value to ATS's more
> extensive model to do similar.... not to mention mutually exclusive in their
> current forms.
> Dave
> On Wed, Sep 20, 2017 at 10:08 AM, Alan Carroll < <>
> wrote:
>> Susan and Dave Thompson were working on something related to that, "crypto
>> proxy". There's a small mention of it by Susan at the Fall 2016 summit in
>> the TLS state slides
>> ( I'd
>> start there and see if you can bug Susan or Good Dave*. Although that work
>> was designed to use an off box crypto engine, the implementation from the
>> ATS point of view is identical to what you're writing about. Susan will be
>> at the Fall 2017 Summit, I'd look her up then as well.
>> * To distinguish from "Evil Dave" Carlin.
>> On Wed, Sep 20, 2017 at 9:44 AM, Jeremy Payne < <>
> wrote:
>>> Thanks guys.. Thats all I needed to know.. Now I can look closer at my
>>> end. Will let you know what I find.
>>> Also, any plans on supporting openssl async, which then allows for
>>> taking full advantage of the Intel QAT engine?
>>> Understood patches/commits are welcome, but just figured there may be
>>> some behind the scene works already started.
>>> Thanks!
>>> On Tue, Sep 19, 2017 at 6:31 PM, Alan Carroll < <>
>>> wrote:
>>> > Susan has also run some performance tests with 7.1.x and openSSL 1.1
>>> > vs.
>>> > openSSL 1.0.2.
>>> >
>>> > On Tue, Sep 19, 2017 at 5:55 PM, Leif Hedstrom < <>
>>> > wrote:
>>> >>
>>> >>
>>> >> On Sep 19, 2017, at 2:20 PM, Jeremy Payne < <>
> wrote:
>>> >>
>>> >> I can link ATS 7.x and 8.x against openssl 1.1.0f, however, for some
>>> >> reason I can't establish a SSL/TLS connection.  Has anyone
>>> >> successfully linked ATS against openssl 1.1.0f  and successfully been
>>> >> able to establish a SSL/TLS session?
>>> >> In other words, is openssl 1.1.0f supported by ATS? If not, what about
>>> >> an earlier version of 1.1.0(x)??
>>> >>
>>> >>
>>> >>
>>> >> Yeh, we’re running current master with OpenSSL v1.1.0f on
>>> >> <>
. Maybe you have some mismatch / issues
>>> >> between
>>> >> headers (when compiling ATS) and runtime?
>>> >>
>>> >> Cheers,
>>> >>
>>> >> — Leif
>>> >>
>>> >



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