Re: [PATCH V6 08/17] perf tools: Add Intel PT support

From: Arnaldo Carvalho de Melo
Date: Mon Jun 22 2015 - 19:00:30 EST

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Em Mon, Jun 22, 2015 at 11:26:34PM +0300, Adrian Hunter escreveu:
> On 22/06/2015 9:24 p.m., Arnaldo Carvalho de Melo wrote:
> >Em Fri, Jun 19, 2015 at 04:41:56PM -0300, Arnaldo Carvalho de Melo escreveu:
> >>Em Fri, Jun 19, 2015 at 10:33:43PM +0300, Adrian Hunter escreveu:
> >>>On 19/06/2015 7:04 p.m., Arnaldo Carvalho de Melo wrote:
> >>>>Em Fri, May 29, 2015 at 04:33:36PM +0300, Adrian Hunter escreveu:
> >>>>>Add support for Intel Processor Trace.
> >>
> >>>>>Intel PT support fits within the new auxtrace infrastructure.
> >>>>>Recording is supporting by identifying the Intel PT PMU,
> >>>>>parsing options and setting up events. Decoding is supported
> >>>>>by queuing up trace data by cpu or thread and then decoding
> >>>>>synchronously delivering synthesized event samples into the
> >>>>>session processing for tools to consume.
> >>
> >>>>So, at this point what commands should I use to test this? I expected to
> >>>>be able to have some command here, in this changeset log, telling me
> >>>>that what has been applied so far + this "Add Intel PT support", can be
> >>>>used in such and such a fashion, obtaining this and that output.
> >>
> >>>>Now I'll go back and look at the cover letter to see what I can do at
> >>>>this point and with access to a Broadwell class machine.
> >>
> >>>Actually you need the next patch "perf tools: Take Intel PT into use" to do anything.
> >>
> >>Yeah, saw that, the title of this patch fooled me into thinking that
> >>Intel PT support was added :-)
> >>
> >>Anyway, stopping for a moment to push stuff ready to Ingo, will get back
> >>to this after that.
> >
> >So, got back to it, added that "take it into use" patch and now trying
> >to follow that documentation:
> >
> >[root@perf4 ~]# perf evlist
> >intel_pt//u
> >sched:sched_switch
> >dummy:u
> >[root@perf4 ~]# perf report
> >[root@perf4 ~]# perf record -e intel_pt//u -a sleep 10
> >[ perf record: Woken up 1 times to write data ]
> >[ perf record: Captured and wrote 0.379 MB perf.data ]
> >[root@perf4 ~]#
> >[root@perf4 ~]#
> >[root@perf4 ~]# perf report
> >[root@perf4 ~]# perf evlist
> >intel_pt//u
> >sched:sched_switch
> >dummy:u
> >[root@perf4 ~]# uname -r
> >4.1.0-rc8
> >[root@perf4 ~]#
> >
> >I am not getting any "intel_pt//u" event, ideas?
>
> Events are synthesized by the decoder. You should see 'instructions:u' events.
>
> What does perf report --stdio give?

Well, away from a Broadwell machine now, applied a few patches more and
I'm now trying BTS, on this Ivy Bridge notebook (MacBook Air):

[ 0.000000] DMI: Apple Inc. MacBookAir5,1/Mac-66F35F19FE2A0D05, BIOS MBA51.88Z.00EF.B02.1211271028 11/27/2012

[ 0.116644] perf_event_intel: PMU erratum BJ122, BV98, HSD29 worked around, HT is on

[ 0.061626] TSC deadline timer enabled
[ 0.061630] smpboot: CPU0: Intel(R) Core(TM) i7-3667U CPU @ 2.00GHz (fam: 06, model: 3a, stepping: 09)
[ 0.061661] Performance Events: PEBS fmt1+, 16-deep LBR, IvyBridge events, full-width counters, Intel PMU driver.
[ 0.061685] ... version: 3
[ 0.061686] ... bit width: 48
[ 0.061687] ... generic registers: 4
[ 0.061688] ... value mask: 0000ffffffffffff
[ 0.061690] ... max period: 0000ffffffffffff
[ 0.061691] ... fixed-purpose events: 3
[ 0.061692] ... event mask: 000000070000000f
[ 0.062587] x86: Booting SMP configuration:
[ 0.062589] .... node #0, CPUs: #1
[ 0.074078] microcode: CPU1 microcode updated early to revision 0x1b, date = 2014-05-29
[ 0.076715] NMI watchdog: enabled on all CPUs, permanently consumes one hw-PMU counter.
[ 0.076825] #2 #3
[ 0.104559] x86: Booted up 1 node, 4 CPUs
[ 0.104563] smpboot: Total of 4 processors activated (19953.49 BogoMIPS)

[root@zoo ~]# perf record -e intel_bts//u --per-thread sleep 5
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.531 MB perf.data ]
[root@zoo ~]# perf evlist
intel_bts//u
dummy:u
[root@zoo ~]#

[root@zoo ~]# perf report --stdio | head -40
# To display the perf.data header info, please use --header/--header-only options.
#
#
# Total Lost Samples: 0
#
# Samples: 0 of event 'intel_bts//u'
# Event count (approx.): 0
#
# Overhead Command Shared Object Symbol
# ........ ....... ............. ......
#

# Samples: 0 of event 'dummy:u'
# Event count (approx.): 0
#
# Overhead Command Shared Object Symbol
# ........ ....... ............. ......
#

# Samples: 22K of event 'branches:u'
# Event count (approx.): 22548
#
# Overhead Command Shared Object Symbol
# ........ ....... ................ ......................
#
9.82% sleep [unknown] [.] 0x00007f8e86c09061
8.28% sleep [unknown] [.] 0x00007f8e86ea4e7e
6.97% sleep [unknown] [.] 0x00007f8e86c09086
5.88% sleep [unknown] [.] 0x00007f8e86e95726
5.28% sleep [unknown] [.] 0x00007f8e86e9730d
4.69% sleep [unknown] [.] 0x00007f8e86b06bc1
4.48% sleep [unknown] [.] 0x00007f8e86c090c7
4.01% sleep [unknown] [.] 0x00007f8e86c09027
4.01% sleep [unknown] [.] 0x00007f8e86c0904c
2.84% sleep [unknown] [.] 0x00007f8e86c0908c
2.74% sleep [unknown] [.] 0x00007f8e86c0909d
2.74% sleep [unknown] [.] 0x00007f8e86c09037
1.20% sleep [unknown] [.] 0x00007f8e86af9c68

-----------------------------------------------------------------

Ok, so it synthesized the branches:u, that don't appear on the 'perf evlist'
output, that is the command I use to see what kinds of events are contained
in a given perf.data file, probably we should add a note there that
branches:u will be synthesized at 'report' time, trying with 'perf script':

[root@zoo ~]# perf script | head -10
:8676 8676 1 branches:u: ffffffff81799b47 [unknown] ([unknown]) => 7f8e86e8bcf0 [unknown] ([unknown])
:8676 8676 1 branches:u: ffffffff81799b47 [unknown] ([unknown]) => 7f8e86e8bcf0 [unknown] ([unknown])
:8676 8676 1 branches:u: 7f8e86e8bcf3 [unknown] ([unknown]) => 7f8e86e8f980 [unknown] ([unknown])
:8676 8676 1 branches:u: ffffffff81799b47 [unknown] ([unknown]) => 7f8e86e8f9a6 [unknown] ([unknown])
:8676 8676 1 branches:u: 7f8e86e8fa11 [unknown] ([unknown]) => 7f8e86e8fa2f [unknown] ([unknown])
:8676 8676 1 branches:u: 7f8e86e8fa33 [unknown] ([unknown]) => 7f8e86e8fa18 [unknown] ([unknown])
:8676 8676 1 branches:u: 7f8e86e8fa33 [unknown] ([unknown]) => 7f8e86e8fa18 [unknown] ([unknown])
:8676 8676 1 branches:u: 7f8e86e8fa3f [unknown] ([unknown]) => 7f8e86e8fc18 [unknown] ([unknown])
:8676 8676 1 branches:u: 7f8e86e8fc20 [unknown] ([unknown]) => 7f8e86e8fc40 [unknown] ([unknown])

The synthesized records looks sane:

[root@zoo ~]# perf report -D | grep PERF_RECORD_ | tail -15
0x36f8 [0x78]: PERF_RECORD_MMAP -1/0: [0xffffffffa0933000(0x5000) @ 0]: x /lib/modules/4.1.0-rc5+/kernel/net/netfilter/xt_CHECKSUM.ko
0x3770 [0x68]: PERF_RECORD_MMAP -1/0: [0xffffffffa0938000(0x18000) @ 0]: x /lib/modules/4.1.0-rc5+/kernel/fs/fuse/fuse.ko
0x37d8 [0x68]: PERF_RECORD_MMAP -1/0: [0xffffffffa0950000(0x5f6affff) @ 0]: x /lib/modules/4.1.0-rc5+/kernel/crypto/ccm.ko
0x3840 [0x20]: PERF_RECORD_ITRACE_START pid: 8676 tid: 8676
0x3860 [0x28]: PERF_RECORD_COMM exec: sleep:8676/8676
0x3888 [0x68]: PERF_RECORD_MMAP2 8676/8676: [0x400000(0x6000) @ 0 fd:01 525758 1481335351]: r-xp /usr/bin/sleep
0x38f0 [0x70]: PERF_RECORD_MMAP2 8676/8676: [0x7f8e86e8b000(0x224000) @ 0 fd:01 534148 868528687]: r-xp /usr/lib64/ld-2.20.so
0x3960 [0x60]: PERF_RECORD_MMAP2 8676/8676: [0x7ffdc21d4000(0x2000) @ 0x7ffdc21d4000 00:00 0 0]: ---p [vdso]
0x39c0 [0x70]: PERF_RECORD_MMAP2 8676/8676: [0x7f8e86ace000(0x3bd000) @ 0 fd:01 531160 868528694]: r-xp /usr/lib64/libc-2.20.so
0x3a30 [0x30]: PERF_RECORD_AUX offset: 0 size: 0x80688 flags: 0 []
0x3a60 [0x30]: PERF_RECORD_EXIT(8676:8676):(8676:8676)
0x3a90 [0x30]: PERF_RECORD_AUX offset: 0x80688 size: 0x3b70 flags: 0 []
0x3ac0 [0x30]: PERF_RECORD_EXIT(8676:8676):(8676:8676)
0x3af0 [0x30]: PERF_RECORD_AUXTRACE size: 0x841f8 offset: 0 ref: 0x531e5c6921c idx: 0 tid: 8676 cpu: -1
0x87d18 [0x8]: PERF_RECORD_FINISHED_ROUNDAggregated stats: (excludes AUX area (e.g. instruction trace) decoded / synthesized events)
[root@zoo ~]#

One of those samples

>>> (0x7f8e86e8fa3f - 0x7f8e86ace000) < 0x3bd000
False

After the libc-2.20.so map

>>> (0x7f8e86e8fa3f - 0x7f8e86e8b000) < 0x224000
True

Ok, so a /usr/lib64/ld-2.20.so sample, and:

[root@zoo ~]# rpm -q glibc-debuginfo
glibc-debuginfo-2.20-8.fc21.x86_64

But then, it didn't even resolve the DSO, which it should, as I did manually :-/

Will continue investigating... Perhaps this is fixed in another patch? What I
have test merged so far is at my tmp.perf/pt branch.

I will still update the cset comments and possibly do some other changes to
preserve bisectability or some other fix so that we get more test output
inserted in the changesets.

- Arnaldo
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Next message: Oleg Nesterov: "Re: [RFC][PATCH 05/13] percpu-rwsem: Optimize readers and reduce global impact"
Previous message: Oleg Nesterov: "Re: [RFC][PATCH 09/13] hotplug: Replace hotplug lock with percpu-rwsem"
In reply to: Adrian Hunter: "Re: [PATCH V6 08/17] perf tools: Add Intel PT support"
Next in thread: Adrian Hunter: "Re: [PATCH V6 08/17] perf tools: Add Intel PT support"
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