[Haskell-cafe] Efficient memory use for tens of thousands of connections

[Ben Bangert]

Forgot to clarify, I setup both projects with cabal using GHC 7.10 with
Stackage nightly from 5/6/15 (per the README's), running under Ubuntu 14.04.

On Thu, May 7, 2015 at 5:12 PM, Ben Bangert <ben at groovie.org> wrote:

> I'm currently evaluating memory overhead for a variety of simple Websocket
> based echo server to get a gauge of minimal memory penalty per connection
> along with SSL overhead per connection.
>
> I've created two websocket servers in Haskell:
> https://github.com/bbangert/ssl-ram-testing/tree/master/Haskell
>
> One using Yesod + jaspers Websockets lib, the other with Yesod + Mishael
> Snoyman's native websocket lib. I was curious what options I might be
> missing that would ensure a more efficient use of memory, at the moment the
> non-SSL seems to use about 48kb per connection, while using Haskell's TLS
> via warp-tls introduces a huge amount of overhead (along with odd handshake
> issues).
>
> Here's what my results look like:
> No SSL
> Program started.
> Tester started.
> Tester finished connecting.
> Waiting: 360  Last Memory Increase: 2
> WARNING: Program hasn't stopped increasing.
> Started with: 2633728
> Ended with: 50896896
> kB per connection: 47.13
>
>
> SSL
> Program started.
> Tester started.
> yesod-customws-tls: HandshakeFailed (Error_Protocol ("bad record
> mac",True,BadRecordMac))
> yesod-customws-tls: HandshakeFailed (Error_Protocol ("bad record
> mac",True,BadRecordMac))
> yesod-customws-tls: HandshakeFailed (Error_Protocol ("bad record
> mac",True,BadRecordMac))
> yesod-customws-tls: HandshakeFailed (Error_Protocol ("bad record
> mac",True,BadRecordMac))
> yesod-customws-tls: HandshakeFailed (Error_Protocol ("bad record
> mac",True,BadRecordMac))
> yesod-customws-tls: HandshakeFailed (Error_Protocol ("bad record
> mac",True,BadRecordMac))
> yesod-customws-tls: HandshakeFailed (Error_Protocol ("bad record
> mac",True,BadRecordMac))
> yesod-customws-tls: HandshakeFailed (Error_Protocol ("bad record
> mac",True,BadRecordMac))
> WARNING: Failed to connect all clients
> Tester finished connecting.
> Waiting: 360  Last Memory Increase: 4
> WARNING: Program hasn't stopped increasing.
> Started with: 3170304
> Ended with: 454221824
> kB per connection: 444.03
>
> SSL Overhead per Conn: 396.90
>
> I wait up to 6 minutes for memory to level out, it never does with or
> without SSL. Is this expected behavior? If not, what options am I missing?
>
> The ssl-ram-testing repo includes full directions on how to reproduce this
> and run this test.
>
> Cheers,
> Ben
>
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