Re: Ftrace for MIPS may hang on SMP system

[Steven Rostedt <rostedt@goodmis.org>]

On Tue, 2010-08-24 at 14:25 +0800, wu zhangjin wrote:

> So, this patch is necessary to fix the deadlock and icache problem on
> RMI XLS and it will also improve the performance via reducing the
> unnecessary ipi interrupt on RML XLS and Cavium.

I was about to mention the performance boost of the patch even on
machines not affected by the lock up.

When you enable function tracing, it can update 22,000 locations. Doing
a cache invalidate 22,000 times in a row, is not very efficient. Only a
full cache flush is needed at the end of the update (except for the
module updates, which are done on a live system).

-- Steve