Re: [PATCH 4/7] perf diff: Fix to sort by baseline field by default

From: Namhyung Kim
Date: Mon Dec 22 2014 - 23:11:39 EST


On Mon, Dec 22, 2014 at 11:45:13AM -0300, Arnaldo Carvalho de Melo wrote:
> Looks better, here I tried running 'perf record usleep 1' in quick
> succession to then run 'perf diff' before and after this patch, got:
>
> Before:
>
> [ssdandy ~]$ cat /tmp/before
> # Event 'cycles'
> #
> # Baseline Delta Shared Object Symbol
> # ........ ....... ................ ..............................
> #
> +36.29% [kernel.vmlinux] [k] __split_vma.isra.31
> 34.55% [kernel.vmlinux] [k] copy_user_generic_unrolled
> +2.45% [kernel.vmlinux] [k] local_clock
> 0.11% +0.02% [kernel.vmlinux] [k] native_write_msr_safe
> 2.12% [kernel.vmlinux] [k] perf_event_comm_output
> +61.13% [kernel.vmlinux] [k] unmap_page_range
> 63.22% libc-2.17.so [.] 0x000000000007c3e0
> [acme@ssdandy ~]$
>
> After:
>
> [acme@ssdandy linux]$ perf diff
> # Event 'cycles'
> #
> # Baseline Delta Shared Object Symbol
> # ........ ....... ................ ..............................
> #
> 63.22% libc-2.17.so [.] 0x000000000007c3e0
> 34.55% [kernel.vmlinux] [k] copy_user_generic_unrolled
> 2.12% [kernel.vmlinux] [k] perf_event_comm_output
> 0.11% +0.02% [kernel.vmlinux] [k] native_write_msr_safe
> +36.29% [kernel.vmlinux] [k] __split_vma.isra.31
> +2.45% [kernel.vmlinux] [k] local_clock
> +61.13% [kernel.vmlinux] [k] unmap_page_range
> [acme@ssdandy linux]$
>
> Which was ok up to the point where symbols that only appeared on the
> second run were not sorted by delta, can you fix that?

I'll do that later.


>
> Please let me know if it is better to apply this one then a followup to
> sort the deltas or if a combined patch to achieve both is best.

I prefer applying this for now and then improve sorting later..

>
> I.e.:
>
> [acme@ssdandy linux]$ perf diff
> # Event 'cycles'
> #
> # Baseline Delta Shared Object Symbol
> # ........ ....... ................ ..............................
> #
> 63.22% libc-2.17.so [.] 0x000000000007c3e0
> 34.55% [kernel.vmlinux] [k] copy_user_generic_unrolled
> 2.12% [kernel.vmlinux] [k] perf_event_comm_output
> 0.11% +0.02% [kernel.vmlinux] [k] native_write_msr_safe
> +61.13% [kernel.vmlinux] [k] unmap_page_range
> +36.29% [kernel.vmlinux] [k] __split_vma.isra.31
> +2.45% [kernel.vmlinux] [k] local_clock
>
> [acme@ssdandy linux]$
>
> Humm, but then wouldn't we be more interested in sorting _everything_ by
> delta?

I don't understand whay you said.. what do you mean by 'everything be
delta'? Is that something other than perf diff -o 1 ?

Thanks,
Namhyung
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