[vidarh]

If the language implementation is an issue when doing this, you're doing something wrong.

I'm working on a contract doing this exact thing at the moment, and unsurprisingly the Ruby code that's in the picture is responsible for just a tiny little fraction of the overall latency.

You should spend most of the time waiting on S3, pretty much no matter what language you choose. If you don't, it's not the fault of whichever language you use.

In fact, S3 performance is so dominant in this type of scenario if you do things properly, that if you want to optimize for speed and can afford to risk data loss (or in our case, the clients poll for confirmation and re-upload data in the rare event of loss), it's generally proving substantially better to write to local disk and do uploading to S3 in the background.