Messages in this thread | | | Date | Fri, 10 Feb 2017 18:14:43 +0900 | From | Namhyung Kim <> | Subject | Re: [PATCHSET 0/4] perf diff: Introduce delta-abs compute method (v2) |
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Hi Ingo,
On Fri, Feb 10, 2017 at 08:41:11AM +0100, Ingo Molnar wrote: > > * Namhyung Kim <namhyung@kernel.org> wrote: > > > Hello, > > > > This patchset adds 'delta-abs' compute method to -c/--compute option. > > The 'delta-abs' is same as 'delta' but shows entries with bigger > > absolute delta first instead of sorting numerically. This is only > > useful together with -o option. > > > > * v2 changes > > - rebase onto acme/perf/core > > - change default option to '-o 1 -c delta-abs' > > > > > > Below is default output (-c delta): > > > > $ perf diff -o 1 -c delta | grep -v ^# | head > > 42.22% +4.97% [kernel.kallsyms] [k] cfb_imageblit > > 0.62% +1.23% [kernel.kallsyms] [k] mutex_lock > > +1.15% [kernel.kallsyms] [k] copy_user_generic_string > > 2.40% +0.95% [kernel.kallsyms] [k] bit_putcs > > 0.31% +0.79% [kernel.kallsyms] [k] link_path_walk > > +0.64% [kernel.kallsyms] [k] kmem_cache_alloc > > 0.00% +0.57% [kernel.kallsyms] [k] __rcu_read_unlock > > +0.45% [kernel.kallsyms] [k] alloc_set_pte > > 0.16% +0.45% [kernel.kallsyms] [k] menu_select > > +0.41% ld-2.24.so [.] do_lookup_x > > > > Now with 'delta-abs' it shows entries have bigger delta value either > > positive or negative. > > > > $ perf diff -o 1 -c delta-abs | grep -v ^# | head > > 42.22% +4.97% [kernel.kallsyms] [k] cfb_imageblit > > 12.72% -3.01% [kernel.kallsyms] [k] intel_idle > > 9.72% -1.31% [unknown] [.] 0x0000000000411343 > > 0.62% +1.23% [kernel.kallsyms] [k] mutex_lock > > +1.15% [kernel.kallsyms] [k] copy_user_generic_string > > 2.40% +0.95% [kernel.kallsyms] [k] bit_putcs > > 0.31% +0.79% [kernel.kallsyms] [k] link_path_walk > > 1.35% -0.71% [kernel.kallsyms] [k] smp_call_function_single > > +0.64% [kernel.kallsyms] [k] kmem_cache_alloc > > 0.00% +0.57% [kernel.kallsyms] [k] __rcu_read_unlock > > Nice! > > BTW., to me the second output looks a lot more intuitive and useful than the > default one.
Thanks!
> > Would it be possible to flip over the default to the 'most useful' options, and > see whether anyone complains?
The patch 4 makes it default.
By the way, the current default (sort by baseline) looks like below:
$ perf diff | grep -v ^# | head 42.22% +4.97% [kernel.kallsyms] [k] cfb_imageblit 12.72% -3.01% [kernel.kallsyms] [k] intel_idle 9.72% -1.31% [unknown] [.] 0x0000000000411343 2.40% +0.95% [kernel.kallsyms] [k] bit_putcs 1.35% -0.71% [kernel.kallsyms] [k] smp_call_function_single 0.62% +1.23% [kernel.kallsyms] [k] mutex_lock 0.31% +0.79% [kernel.kallsyms] [k] link_path_walk 0.16% +0.45% [kernel.kallsyms] [k] menu_select 0.00% +0.57% [kernel.kallsyms] [k] __rcu_read_unlock
While this example doesn't show much difference, it could be..
Thanks, Namhyung
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