CPU usage

[JeanneLespinasse]

Hi everyone,

I'm using node-thumbnail to create thumbs from HD pictures that my client load trough some king of drive.

My problem is that I have 8 cpus, at first the concurrency was of 8, but it completely blocked all the process apart from the thumbnail creation. (htop showed me that it only use one CPU at more than 100% though).

I made some test, and in the end, it seems like the best is to put the concurrency to 1. It is far way faster (less than a second) to create the thumbs, and the usage of my CPU is about 50%.

My problem is now when there are multiple client trying to create thumbs at the same time, seems like the best is concurrency at 1. But it use it at 100% and so slow down the server.

Do you have any idea why it is best to have concurrency to 1 than 8 ? And what could I do to make it more smooth ?

Thanks in advance,
Sorry for the english,

Jeanne