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Message-ID: <20150106161607.GA15396@kernel.org>
Date: Tue, 6 Jan 2015 13:16:07 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: kan.liang@...el.com
Cc: jolsa@...hat.com, namhyung@...nel.org,
linux-kernel@...r.kernel.org, ak@...ux.intel.com
Subject: Re: [PATCH V6 1/1] perf tool: perf diff support for different
binaries
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@...el.com 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@...hat.com>
> 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@...alhost 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@...andy l]# perf --version
perf version 3.1.rc9.37.g3f2728.dirty
commit 3f2728bdb6a4cad0d18b09d03e2008121c902751
Author: Arnaldo Carvalho de Melo <acme@...hat.com>
Date: Wed Oct 5 16:10:06 2011 -0300
perf report: Add option to show total period
I get:
[root@...andy l]# gcc example_v1.c -o example
[root@...andy 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@...andy l]# gcc example_v2.c -o example
[root@...andy 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@...andy 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@...andy 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.
- Arnaldo
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