Re: libosmocore stderr log performance / blocking

Hi,

On 9/29/20 11:26 AM, Harald Welte wrote:

So what I think would be good is:

• If the write_queue is empty, attempt a synchronous, non-blocking write to stderr/file.
• Only if that write returns short (in the extreme case '0'), enqueue the [remainder of the] log message to the write_queue for delayed storage.

Fine with this approach, I was going to suggest that too while reading your last comments. The important point here is changing the fd to be non-blocking, all the rest is basically about how to keep ordering and delays at minimum once we hit a would-block situation. In any case, I'd gor for: when pushing stuff to the fd from the queue, also push until short-write is hit, not only 1 msgb per select().

This way we should get the best of both worlds: More or less unmodified behavior for 99% of all cases, while avoiding any delays in those few situations where right now we are stalling/blocking due to a full stdio buffer.

ACK.