On Donnerstag, 10. August 2017 04:13:25 CEST Namhyung Kim wrote: > Hi Milian, > > On Sun, Aug 06, 2017 at 11:24:43PM +0200, Milian Wolff wrote: > > On one hand this ensures that the memory is properly freed when > > the DSO gets freed. On the other hand this significantly speeds up > > the processing of the callchain nodes when lots of srclines are > > requested. For one of my data files e.g.: > > > > Before: > > Performance counter stats for 'perf report -s srcline -g srcline -- stdio': > > 52496.495043 task-clock (msec) # 0.999 CPUs utilized > > > > 634 context-switches # 0.012 K/sec > > > > 2 cpu-migrations # 0.000 K/sec > > > > 191,561 page-faults # 0.004 M/sec > > > > 165,074,498,235 cycles # 3.144 GHz > > 334,170,832,408 instructions # 2.02 insn per > > cycle > > > > 90,220,029,745 branches # 1718.591 M/sec > > > > 654,525,177 branch-misses # 0.73% of all > > branches > > > > 52.533273822 seconds time elapsedProcessed 236605 events and lost 40 > > chunks!> > > After: > > Performance counter stats for 'perf report -s srcline -g srcline -- stdio': > > 22606.323706 task-clock (msec) # 1.000 CPUs utilized > > > > 31 context-switches # 0.001 K/sec > > > > 0 cpu-migrations # 0.000 K/sec > > > > 185,471 page-faults # 0.008 M/sec > > > > 71,188,113,681 cycles # 3.149 GHz > > > > 133,204,943,083 instructions # 1.87 insn per > > cycle > > > > 34,886,384,979 branches # 1543.214 M/sec > > > > 278,214,495 branch-misses # 0.80% of all > > branches > > > > 22.609857253 seconds time elapsed > > > > Note that the difference is only this large when `--inline` is not > > passed. In such situations, we would use the inliner cache and > > thus do not run this code path that often. > > > > I think that this cache should actually be used in other places, too. > > When looking at the valgrind leak report for perf report, we see tons > > of srclines being leaked, most notably from calls to > > hist_entry__get_srcline. The problem is that get_srcline has many > > different formatting options (show_sym, show_addr, potentially even > > unwind_inlines when calling __get_srcline directly). As such, the > > srcline cannot easily be cached for all calls, or we'd have to add > > caches for all formatting combinations (6 so far). An alternative > > would be to remove the formatting options and handle that on a > > different level - i.e. print the sym/addr on demand wherever we > > actually output something. And the unwind_inlines could be moved into > > a separate function that does not return the srcline. > > Agreed. Also I guess no need to unwind anymore to get a srcfile for > an entry with your change.
Does this mean I should respin the patch series with the above changes integrated? Or can we get this in first and then continue with the cleanup as described above later on? Thanks -- Milian Wolff | milian.wo...@kdab.com | Senior Software Engineer KDAB (Deutschland) GmbH&Co KG, a KDAB Group company Tel: +49-30-521325470 KDAB - The Qt Experts
