RE: [PATCH V6 1/1] perf tool: perf diff support for different binaries
From: Liang, Kan
Date: Mon Jan 12 2015 - 13:07:18 EST
> Em Tue, Jan 06, 2015 at 11:53:56AM -0300, Arnaldo Carvalho de Melo
> escreveu:
> > Em Tue, Dec 02, 2014 at 10:39:18AM -0500, kan.liang@xxxxxxxxx escreveu:
> > > Currently, the perf diff only works with same binaries. That's
> > > because it compares the symbol start address. It doesn't work if the
> > > perf.data comes from different binaries. This patch matches the
> function names.
>
> > Sorry Kan, I saw these patches, its just that it the above statement
> > looked completely strange to me, i.e. of course it should look at the
> > dso name, then at the symbol name, comparing via addresses makes no
> > sense to me, so I kept leaving this patch to look after processing
> > other patches and doing other things, then the year end holidays, etc.
>
> > So now I'm looking at old code, from 2009:
>
> > commit 604c5c92972dcb4b98be34775452d09a5d4ec248
> > Author: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> > Date: Wed Dec 16 14:09:53 2009 -0200
>
> > perf diff: Change the default sort order to "dso,symbol"
>
> <SNIP>
>
> > Now I'm trying to figure out _when_ this got broken, what was the
> > reasoning for that code to have changed in a way that made it not match
> by dso_name, symbol_name.
>
> <SNIP>
>
> > > New perf diff result.
> > > [lk@localhost perf_diff]$ perf diff example_v1.data example_v2.data
> > > [kernel.vmlinux] [k] __perf_event_task_sched_out
> > > 0.00% [kernel.vmlinux] [k] apic_timer_interrupt
> > > [kernel.vmlinux] [k] idle_cpu
> > > [kernel.vmlinux] [k] intel_pstate_timer_func
> > > [kernel.vmlinux] [k] native_read_msr_safe
> > > 0.00% [kernel.vmlinux] [k] native_read_tsc
> > > 0.00% [kernel.vmlinux] [k] native_write_msr_safe
> > > [kernel.vmlinux] [k] ntp_tick_length
> > > 0.00% [kernel.vmlinux] [k] rb_erase
> > > 0.00% [kernel.vmlinux] [k] tick_sched_timer
> > > 0.00% [kernel.vmlinux] [k] unmap_single_vma
> > > 0.00% [kernel.vmlinux] [k] update_wall_time
> > > 0.00% example [.] f1
> > > 46.24% -0.08% example [.] f2
> > > 53.71% +0.11% example [.] f3
> > > 0.02% example [.] main
>
> So, with:
>
> [root@ssdandy l]# perf --version
> perf version 3.1.rc9.37.g3f2728.dirty
>
> commit 3f2728bdb6a4cad0d18b09d03e2008121c902751
> Author: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> Date: Wed Oct 5 16:10:06 2011 -0300
>
> perf report: Add option to show total period
>
> I get:
>
> [root@ssdandy l]# gcc example_v1.c -o example [root@ssdandy l]# perf
> record -F 10000 ./example [ perf record: Woken up 7 times to write data ]
> [ perf record: Captured and wrote 1.739 MB perf.data (~75981 samples) ]
> [root@ssdandy l]# gcc example_v2.c -o example [root@ssdandy l]# perf
> record -F 10000 ./example [ perf record: Woken up 7 times to write data ]
> [ perf record: Captured and wrote 1.733 MB perf.data (~75735 samples) ]
> [root@ssdandy l]# perf diff
> # Baseline Delta Shared Object Symbol
> # ........ .......... ................. ...........................
> #
> 0.00% +53.60% example [.] f3
> 54.23% -8.02% example [.] f2
> 0.02% [kernel.kallsyms] [k] native_read_msr_safe
> 0.04% -0.01% [kernel.kallsyms] [k] native_write_msr_safe
> 0.01% [kernel.kallsyms] [k] thermal_interrupt
> 0.01% [kernel.kallsyms] [k] apic_timer_interrupt
> 0.00% [kernel.kallsyms] [k] update_wall_time
> 0.00% example [.] main
> 0.00% example [.] f1
> 0.00% [kernel.kallsyms] [k] notifier_call_chain
> 0.00% [kernel.kallsyms] [k] _raw_spin_lock_irqsave
> 0.01% [kernel.kallsyms] [k] _raw_spin_lock
> 0.00% [kernel.kallsyms] [k] native_read_tsc
> 0.00% [kernel.kallsyms] [k] task_tick_fair
> 0.00% [kernel.kallsyms] [k] account_user_time
> 0.00% [kernel.kallsyms] [k] unmap_page_range
> 0.00% [kernel.kallsyms] [k] kfree
> 0.00% [kernel.kallsyms] [k] sidtab_context_to_sid
> 0.00% ld-2.17.so [.] _dl_relocate_object
> 0.00% [kernel.kallsyms] [k] update_cfs_rq_blocked_load
> 0.00% [kernel.kallsyms] [k] perf_event_task_tick
> 0.00% [kernel.kallsyms] [k] rcu_irq_enter
> 0.00% [kernel.kallsyms] [k] run_timer_softirq
> 0.00% [kernel.kallsyms] [k] task_cputime
> 0.00% [kernel.kallsyms] [k] exit_idle
> 0.00% [kernel.kallsyms] [k] __update_cpu_load
> 0.00% [kernel.kallsyms] [k] _raw_spin_unlock_irqrestore
> 0.00% [kernel.kallsyms] [k] account_process_tick
> 0.00% [kernel.kallsyms] [k] raise_softirq
> 0.00% [kernel.kallsyms] [k] update_process_times
> 0.01% [kernel.kallsyms] [k] native_sched_clock
> 0.00% [kernel.kallsyms] [k] therm_throt_process
> 0.00% [kernel.kallsyms] [k] intel_thermal_interrupt
> 0.01% [kernel.kallsyms] [k] update_vsyscall
> 0.00% [kernel.kallsyms] [k] jiffies_to_timeval
> 0.00% [kernel.kallsyms] [k] intel_pstate_timer_func
> 0.00% [kernel.kallsyms] [k] x86_pmu_disable
> 0.00% [kernel.kallsyms] [k] __do_softirq
> 0.00% [kernel.kallsyms] [k] hrtimer_interrupt
> 0.00% [kernel.kallsyms] [k] tick_sched_do_timer
> 0.00% [kernel.kallsyms] [k] do_softirq
> 0.00% [kernel.kallsyms] [k] sidtab_search_core
> 0.00% [kernel.kallsyms] [k] selinux_inode_permission
> 0.00% [kernel.kallsyms] [k] kmem_cache_alloc
> 0.00% [kernel.kallsyms] [k] finish_wait
> [root@ssdandy l]#
>
> After this there were the changes to allow using the hists browser to be
> used with 'top' and 'diff' was left broken for a while, I'll see if I can continue
> bisecting this after lunch.
>
Hi Arnaldo,
I'm not quite what should I modified for this patch.
I think it may be broken after the commit as below (not test)
9c443dfdd31e ("perf diff: Fix support for all --sort combinations").
Should I change the patch description to bug fix, remove the examples,
and remove the changes in Documentation?
It's only one-line change, so I will keep the code part.
What do you think?
Thanks,
Kan
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