[Opensim-users] LSL HTTP server is slow

[Melanie]

I suppose this is from current master. HTTP-In used to be slow, as
slow a 1 request/s, but this was fixed in Avination ages ago and has
come to 0.9 in the course of the merge.

- Melanie

On 14/01/2016 00:42, Jeff Kelley wrote:
> Here is a quick & dirty benchmark to measure how fast we can stuff 
> data from the real world to a script using the LSL HTTP server. Data 
> may come from some sensor or human interaction device, maybe motion 
> capture, a Wii Remote, a Kinect ... and would control a simulation in 
> real-time.
> 
> The benchmark sends requests in the form seq=n, where n is an 
> incrementing sequence number. Any sequence gap on the receiver side 
> will indicate a lost message. There is an important assumption : we 
> are not interested in the reply and don't care reading it. This makes 
> a HUGE difference.
> 
> Code :
> https://github.com/jeff-kelley/opensim-utils/tree/master/lsl_http-benchmark
> 
> Let's begin with the LSL script. It allocates a url then wait for a 
> request. GET and POST are supported. It checks the received sequence 
> number against the expected number and complains it they mismatch. 
> Finally, the script counts and display the number of requests it 
> receives every second.
> 
> On the client side, I chose Perl and the Net::HTTP class. No doubt 
> that could be written in Python, Ruby, C#, even PHP. The client opens 
> a HTTP connection in KeepAlive, then emit requests at a steady rate. 
> Inside the loop, the HTTP write is timed, and the wait to the next 
> request is computed.
> 
> The variable $reqSec controls the number of request per second. 
> Performing the test with different values gives an idea of the 
> overall performance.
> 
> Now for the unbelievable :
> 
> [09:56] Primitive: Requests/second : 207
> [09:56] Primitive: Requests/second : 198
> [09:56] Primitive: Requests/second : 220
> [09:56] Primitive: Requests/second : 198
> [09:56] Primitive: Requests/second : 214
> [09:56] Primitive: Requests/second : 206
> [09:56] Primitive: Requests/second : 207
> [09:56] Primitive: Requests/second : 213
> [09:56] Primitive: Requests/second : 207
> 
> Between two machine on a LAN, my figure is 200. Holy cow! This is 
> more than enough for a smooth simulation. As a bonus, you get a 
> high-speed, high-jitter event source.
> 
> LSL HTTP server slow ?
> 
> Not !
> 
> 
> 
> -- Jeff
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