Messages in this thread | | | Date | Fri, 16 May 2014 16:05:51 +0200 | From | Jiri Olsa <> | Subject | Re: [PATCH 6/6] perf: Add dcacheline sort |
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On Fri, May 16, 2014 at 09:30:58AM -0400, Don Zickus wrote: > On Fri, May 16, 2014 at 01:47:57PM +0200, Jiri Olsa wrote: > > On Tue, May 13, 2014 at 12:48:17PM -0400, Don Zickus wrote: > > > In perf's 'mem-mode', one can get access to a whole bunch of details specific to a > > > particular sample instruction. A bunch of those details relate to the data > > > address. > > > > > > One interesting thing you can do with data addresses is to convert them into a unique > > > cacheline they belong too. Organizing these data cachelines into similar groups and sorting > > > them can reveal cache contention. > > > > > > This patch creates an alogorithm based on various sample details that can help group > > > entries together into data cachelines and allows 'perf report' to sort on it. > > > > > > The algorithm relies on having proper mmap2 support in the kernel to help determine > > > if the memory map the data address belongs to is private to a pid or globally shared. > > > > > > The alogortithm is as follows: > > > > > > o group cpumodes together > > > o group entries with discovered maps together > > > o sort on major, minor, inode and inode generation numbers > > > o if userspace anon, then sort on pid > > > o sort on cachelines based on data addresses > > > > needs some collumn width refresh or something..? ;-) > > Not sure what you mean here. > > > > > # Overhead Data Cacheline > > # ........ .......................
header not being wide enough to cover the longest data
> > # > > 5.42% [k] 0xffff8801ed832c40 > > 5.29% [.] sys_errlist@@GLIBC_2.12+0xffffffcbf7dfc1ff > > 3.16% [k] 0xffffffffff5690c0 > > > > > > also I've got again perf hanged up on opening device file > > > > [jolsa@krava perf]$ sudo strace -p 29445 > > Process 29445 attached > > open("/dev/snd/pcmC0D0p", O_RDONLY^CProcess 29445 detached > > > > another one I recall was /dev/dri/card0 touched by X server > > > > I guess those device files allow to mmap memory and we recorded > > memory access there.. we need check for this and do not try to > > open device files > > Ok. And that problem doesn't happen when my patch is not applied? I am > not sure how this patch causes open device hangs. I'll try to run this on > a box with X server running to duplicate.
I think it came with the memory profiling, because we treat data areas as dsos.. open and look for symbols
jirka
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