[erlang-questions] New ssl vs Google Chrome

Per Hedeland <>
Wed Mar 7 09:22:21 CET 2012

Sorry, forgot to mention that the DH cipher suites were not enabled for
"new", since they're pretty CPU-intensive and weren't supported by "old"
anyway. I.e. all tests used AES256-SHA a.k.a.


Per Hedeland <> wrote:
>Is anyone else seeing (or even better, fixing:-) performance problems
>when Chrome is used towards a HTTPS server with "new ssl"? With the
>server running on a "pretty slow" PPC system, I'm seeing a simple test
>(connect and log in to webui) where beam + ssl_esock used a total of ~ 1
>second CPU with "old ssl" (in R14B01) use upwards of 12 seconds CPU with
>"new" (still R14B01) - i.e. essentially unusable.
>Running ssldump reveals that Chrome's SSL behavior is pretty braindead
>(a technical term) - it opens loads of SSL connections, most of them
>without session reuse, and if it's unhappy with the server cert it will
>also close most of them without even completing the client side of the
>handshake, let alone doing any application data transfer.
>The test used a cert with a 4096 bit RSA key - dropping it to 1024 makes
>the problem basically go away (~ 0.4 second CPU with "new"). This would
>seem to confirm that the bad performance is due to the many full
>handshakes generated by Chrome - but it's obviously not a fix, nor does
>it explain the huge difference between old and new (the Chrome behavior
>is basically the same with both).
>I tried doing just the RSA signing with a 4096 bit key on the "pretty
>slow" system - via public_key it uses ~ 1.4 seconds CPU, "directly" with
>libcrypto ~ 0.5 seconds. This seems rather strange, since as far as I
>can see there isn't much code executed besides the libcrypto call when
>public_key is used. And there still remains an unexplained factor of 4
>or more in lost performance.
>The performance seems to have improved a bit in R14B04, with 6 seconds
>CPU for the above test - but it's still not really usable, and I don't
>see anything relevant in the READMEs. I should add that the comparison
>above also used different versions of yaws, 1.62 vs 1.91 - but it's hard
>to see how this could have a significant impact on the SSL handshake.
>Any info appreciated...
>--Per Hedeland
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