On Mon, May 19, 2014 at 03:13:53PM -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 > > The 'dcacheline' sort option in 'perf report' only works in 'mem-mode'. > > Sample output: > > # > # Samples: 206 of event 'cpu/mem-loads/pp' > # Total weight : 2534 > # Sort order : dcacheline,pid > # > # Overhead Samples > Data Cacheline Command: Pid > # ........ ............ > ...................................................................... > .................. > # > 13.22% 1 [k] 0xffff88042f08ebc0 > swapper: 0 > 9.27% 1 [k] 0xffff88082e8cea80 > swapper: 0 > 3.59% 2 [k] 0xffffffff819ba180 > swapper: 0 > 0.32% 1 [k] > arch_trigger_all_cpu_backtrace_handler_na.23901+0xffffffffffffffe0 > swapper: 0 > 0.32% 1 [k] timekeeper_seq+0xfffffffffffffff8 > swapper: 0 > > Note: Added a '+1' to symlen size in hists__calc_col_len to prevent the next > column > from prematurely tabbing over and mis-aligning. Not sure what the problem is.
I think thats the extra '+' sign ;-) so +1 seems ok jirka -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
