On 07/05/2013 08:45 PM, Peter Zijlstra wrote: > On Fri, Jul 05, 2013 at 11:19:31AM +0800, Yan, Zheng wrote: >> On 07/04/2013 08:41 PM, Peter Zijlstra wrote: >>> It should be *optional*, also wtf is that parent_ctx thing for? >> >> parent_ctx is for the fork() case, used for checking if the callstack feature >> is enabled for the parent task. If yes, clone parent task's LBR stack. >> For the simple program below: > > So there's a problem with all this; contexts aren't strict per task, we > play games with them in perf_event_context_sched_out(). We'd have to > disable that context switch optimization for LBR stack to work and > that's massively expensive. >
Sorry, I didn't realize the optimization. I will describe my change in more details in the further. Yan, Zheng > If you actually did that, you again fail for not having mentioned this > in your changelog. > > I'm starting to not want to read patches from you; going through them is > just too much effort, I might as well write the stuff myself :/ > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
