On Wed, Dec 11, 2013 at 02:36:16PM +0200, Alexander Shishkin wrote: > Instruction tracing PMUs are capable of recording a log of instruction > execution flow on a cpu core, which can be useful for profiling and crash > analysis. This patch adds itrace infrastructure for perf events and the > rest of the kernel to use. > > Since such PMUs can produce copious amounts of trace data, it may be > impractical to process it inside the kernel in real time, but instead export > raw trace streams to userspace for subsequent analysis. Thus, itrace PMUs > may export their trace buffers, which can be mmap()ed to userspace from a > perf event fd with a PERF_EVENT_ITRACE_OFFSET offset. To that end, perf > is extended to work with multiple ring buffers per event, reusing the > ring_buffer code in an attempt to reduce complexity.
Please read the thread here: https://lkml.org/lkml/2008/12/4/64 On my thoughts of this creative mmap() usage. tl;dr: no f*cking way. -- 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/
