Re: [PATCH] perf session: Add option to copy events when queueing

From: David Ahern
Date: Fri Oct 25 2013 - 12:04:30 EST

On 10/24/13 8:07 AM, Arnaldo Melo wrote:
What I thought was since we have to allocate memory _somewhere_ we could
size the ring buffer in such a way that it would be big enough for us to
leave those referenced entries there, not consumed, till we actually
consume them when reordering the events, and if we run out of space, the
kernel would just use LOST records, and not overwrite anything.

The tail pointer should only be moved up once all the events have been flushed from the ordered samples queue. Right now the tail is moved up when the event is read from the mmap (the patch in the other email thread withstanding). The problem is that we do not have any linkage between the event and the mmap that it came from; that information is lost when the event is added to the ordered samples queue.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at