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From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: Clark Williams <williams@redhat.com>,
	linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
	Sandipan Das <sandipan@linux.ibm.com>,
	Jiri Olsa <jolsa@redhat.com>,
	Maynard Johnson <maynard@us.ibm.com>,
	"Naveen N . Rao" <naveen.n.rao@linux.vnet.ibm.com>,
	Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>,
	Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>,
	Arnaldo Carvalho de Melo <acme@redhat.com>
Subject: [PATCH 11/27] perf powerpc: Fix callchain ip filtering
Date: Wed, 25 Jul 2018 14:59:45 -0300	[thread overview]
Message-ID: <20180725180001.15108-12-acme@kernel.org> (raw)
In-Reply-To: <20180725180001.15108-1-acme@kernel.org>

From: Sandipan Das <sandipan@linux.ibm.com>

For powerpc64, redundant entries in the callchain are filtered out by
determining the state of the return address and the stack frame using
DWARF debug information.

For making these filtering decisions we must analyze the debug
information for the location corresponding to the program counter value,
i.e. the first entry in the callchain, and not the LR value; otherwise,
perf may filter out either the second or the third entry in the
callchain incorrectly.

This can be observed on a powerpc64le system running Fedora 27 as shown
below.

Case 1 - Attaching a probe at inet_pton+0x8 (binary offset 0x15af28).
         Return address is still in LR and a new stack frame is not yet
         allocated. The LR value, i.e. the second entry, should not be
	 filtered out.

  # objdump -d /usr/lib64/libc-2.26.so | less
  ...
  000000000010eb10 <gaih_inet.constprop.7>:
  ...
    10fa48:       78 bb e4 7e     mr      r4,r23
    10fa4c:       0a 00 60 38     li      r3,10
    10fa50:       d9 b4 04 48     bl      15af28 <inet_pton+0x8>
    10fa54:       00 00 00 60     nop
    10fa58:       ac f4 ff 4b     b       10ef04 <gaih_inet.constprop.7+0x3f4>
  ...
  0000000000110450 <getaddrinfo>:
  ...
    1105a8:       54 00 ff 38     addi    r7,r31,84
    1105ac:       58 00 df 38     addi    r6,r31,88
    1105b0:       69 e5 ff 4b     bl      10eb18 <gaih_inet.constprop.7+0x8>
    1105b4:       78 1b 71 7c     mr      r17,r3
    1105b8:       50 01 7f e8     ld      r3,336(r31)
  ...
  000000000015af20 <inet_pton>:
    15af20:       0b 00 4c 3c     addis   r2,r12,11
    15af24:       e0 c1 42 38     addi    r2,r2,-15904
    15af28:       a6 02 08 7c     mflr    r0
    15af2c:       f0 ff c1 fb     std     r30,-16(r1)
    15af30:       f8 ff e1 fb     std     r31,-8(r1)
  ...

  # perf probe -x /usr/lib64/libc-2.26.so -a inet_pton+0x8
  # perf record -e probe_libc:inet_pton -g ping -6 -c 1 ::1
  # perf script

Before:

  ping  4507 [002] 514985.546540: probe_libc:inet_pton: (7fffa7dbaf28)
              7fffa7dbaf28 __GI___inet_pton+0x8 (/usr/lib64/libc-2.26.so)
              7fffa7d705b4 getaddrinfo+0x164 (/usr/lib64/libc-2.26.so)
                 13fb52d70 _init+0xbfc (/usr/bin/ping)
              7fffa7c836a0 generic_start_main.isra.0+0x140 (/usr/lib64/libc-2.26.so)
              7fffa7c83898 __libc_start_main+0xb8 (/usr/lib64/libc-2.26.so)
                         0 [unknown] ([unknown])

After:

  ping  4507 [002] 514985.546540: probe_libc:inet_pton: (7fffa7dbaf28)
              7fffa7dbaf28 __GI___inet_pton+0x8 (/usr/lib64/libc-2.26.so)
              7fffa7d6fa54 gaih_inet.constprop.7+0xf44 (/usr/lib64/libc-2.26.so)
              7fffa7d705b4 getaddrinfo+0x164 (/usr/lib64/libc-2.26.so)
                 13fb52d70 _init+0xbfc (/usr/bin/ping)
              7fffa7c836a0 generic_start_main.isra.0+0x140 (/usr/lib64/libc-2.26.so)
              7fffa7c83898 __libc_start_main+0xb8 (/usr/lib64/libc-2.26.so)
                         0 [unknown] ([unknown])

Case 2 - Attaching a probe at _int_malloc+0x180 (binary offset 0x9cf10).
         Return address in still in LR and a new stack frame has already
         been allocated but not used. The caller's caller, i.e. the third
	 entry, is invalid and should be filtered out and not the second
	 one.

  # objdump -d /usr/lib64/libc-2.26.so | less
  ...
  000000000009cd90 <_int_malloc>:
     9cd90:       17 00 4c 3c     addis   r2,r12,23
     9cd94:       70 a3 42 38     addi    r2,r2,-23696
     9cd98:       26 00 80 7d     mfcr    r12
     9cd9c:       f8 ff e1 fb     std     r31,-8(r1)
     9cda0:       17 00 e4 3b     addi    r31,r4,23
     9cda4:       d8 ff 61 fb     std     r27,-40(r1)
     9cda8:       78 23 9b 7c     mr      r27,r4
     9cdac:       1f 00 bf 2b     cmpldi  cr7,r31,31
     9cdb0:       f0 ff c1 fb     std     r30,-16(r1)
     9cdb4:       b0 ff c1 fa     std     r22,-80(r1)
     9cdb8:       78 1b 7e 7c     mr      r30,r3
     9cdbc:       08 00 81 91     stw     r12,8(r1)
     9cdc0:       11 ff 21 f8     stdu    r1,-240(r1)
     9cdc4:       4c 01 9d 41     bgt     cr7,9cf10 <_int_malloc+0x180>
     9cdc8:       20 00 a4 2b     cmpldi  cr7,r4,32
  ...
     9cf08:       00 00 00 60     nop
     9cf0c:       00 00 42 60     ori     r2,r2,0
     9cf10:       e4 06 ff 7b     rldicr  r31,r31,0,59
     9cf14:       40 f8 a4 7f     cmpld   cr7,r4,r31
     9cf18:       68 05 9d 41     bgt     cr7,9d480 <_int_malloc+0x6f0>
  ...
  000000000009e3c0 <tcache_init.part.4>:
  ...
     9e420:       40 02 80 38     li      r4,576
     9e424:       78 fb e3 7f     mr      r3,r31
     9e428:       71 e9 ff 4b     bl      9cd98 <_int_malloc+0x8>
     9e42c:       00 00 a3 2f     cmpdi   cr7,r3,0
     9e430:       78 1b 7e 7c     mr      r30,r3
  ...
  000000000009f7a0 <__libc_malloc>:
  ...
     9f8f8:       00 00 89 2f     cmpwi   cr7,r9,0
     9f8fc:       1c ff 9e 40     bne     cr7,9f818 <__libc_malloc+0x78>
     9f900:       c9 ea ff 4b     bl      9e3c8 <tcache_init.part.4+0x8>
     9f904:       00 00 00 60     nop
     9f908:       e8 90 22 e9     ld      r9,-28440(r2)
  ...

  # perf probe -x /usr/lib64/libc-2.26.so -a _int_malloc+0x180
  # perf record -e probe_libc:_int_malloc -g ./test-malloc
  # perf script

Before:

  test-malloc  6554 [009] 515975.797403: probe_libc:_int_malloc: (7fffa6e6cf10)
              7fffa6e6cf10 _int_malloc+0x180 (/usr/lib64/libc-2.26.so)
              7fffa6dd0000 [unknown] (/usr/lib64/libc-2.26.so)
              7fffa6e6f904 malloc+0x164 (/usr/lib64/libc-2.26.so)
              7fffa6e6f9fc malloc+0x25c (/usr/lib64/libc-2.26.so)
                  100006b4 main+0x38 (/home/testuser/test-malloc)
              7fffa6df36a0 generic_start_main.isra.0+0x140 (/usr/lib64/libc-2.26.so)
              7fffa6df3898 __libc_start_main+0xb8 (/usr/lib64/libc-2.26.so)
                         0 [unknown] ([unknown])

After:

  test-malloc  6554 [009] 515975.797403: probe_libc:_int_malloc: (7fffa6e6cf10)
              7fffa6e6cf10 _int_malloc+0x180 (/usr/lib64/libc-2.26.so)
              7fffa6e6e42c tcache_init.part.4+0x6c (/usr/lib64/libc-2.26.so)
              7fffa6e6f904 malloc+0x164 (/usr/lib64/libc-2.26.so)
              7fffa6e6f9fc malloc+0x25c (/usr/lib64/libc-2.26.so)
                  100006b4 main+0x38 (/home/sandipan/test-malloc)
              7fffa6df36a0 generic_start_main.isra.0+0x140 (/usr/lib64/libc-2.26.so)
              7fffa6df3898 __libc_start_main+0xb8 (/usr/lib64/libc-2.26.so)
                         0 [unknown] ([unknown])

Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Maynard Johnson <maynard@us.ibm.com>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Fixes: a60335ba3298 ("perf tools powerpc: Adjust callchain based on DWARF debug info")
Link: http://lkml.kernel.org/r/24bb726d91ed173aebc972ec3f41a2ef2249434e.1530724939.git.sandipan@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/arch/powerpc/util/skip-callchain-idx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/arch/powerpc/util/skip-callchain-idx.c b/tools/perf/arch/powerpc/util/skip-callchain-idx.c
index ef5d59a5742e..264fc0158100 100644
--- a/tools/perf/arch/powerpc/util/skip-callchain-idx.c
+++ b/tools/perf/arch/powerpc/util/skip-callchain-idx.c
@@ -246,7 +246,7 @@ int arch_skip_callchain_idx(struct thread *thread, struct ip_callchain *chain)
 	if (!chain || chain->nr < 3)
 		return skip_slot;
 
-	ip = chain->ips[2];
+	ip = chain->ips[1];
 
 	thread__find_symbol(thread, PERF_RECORD_MISC_USER, ip, &al);
 
-- 
2.14.4

  parent reply	other threads:[~2018-07-25 17:59 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-25 17:59 [GIT PULL 00/27] perf/core improvements and fixes Arnaldo Carvalho de Melo
2018-07-25 17:59 ` [PATCH 01/27] perf tests: Check that complex event name is parsed correctly Arnaldo Carvalho de Melo
2018-07-25 17:59 ` [PATCH 02/27] perf hists: Clarify callchain disabling when available Arnaldo Carvalho de Melo
2018-07-25 17:59 ` [PATCH 03/27] perf cs-etm: Introduce invalid address macro Arnaldo Carvalho de Melo
2018-07-25 17:59 ` [PATCH 04/27] perf cs-etm: Bail out immediately for instruction sample failure Arnaldo Carvalho de Melo
2018-07-25 17:59 ` [PATCH 05/27] Revert "perf list: Add s390 support for detailed/verbose PMU event description" Arnaldo Carvalho de Melo
2018-07-25 17:59 ` [PATCH 06/27] perf list: Add s390 support for detailed PMU event description Arnaldo Carvalho de Melo
2018-07-25 17:59 ` [PATCH 07/27] perf json: Add s390 transaction counter definition Arnaldo Carvalho de Melo
2018-07-25 17:59 ` [PATCH 08/27] perf stat: Add transaction flag (-T) support for s390 Arnaldo Carvalho de Melo
2018-07-25 17:59 ` [PATCH 09/27] perf kvm: Fix subcommands on s390 Arnaldo Carvalho de Melo
2018-07-25 17:59 ` [PATCH 10/27] perf list: Add missing documentation for --desc and --debug options Arnaldo Carvalho de Melo
2018-07-25 17:59 ` Arnaldo Carvalho de Melo [this message]
2018-07-25 17:59 ` [PATCH 12/27] perf powerpc: Fix callchain ip filtering when return address is in a register Arnaldo Carvalho de Melo
2018-07-25 17:59 ` [PATCH 13/27] perf tests: Fix record+probe_libc_inet_pton.sh for powerpc64 Arnaldo Carvalho de Melo
2018-07-25 17:59 ` [PATCH 14/27] perf tests: Fix record+probe_libc_inet_pton.sh to ensure cleanups Arnaldo Carvalho de Melo
2018-07-25 17:59 ` [PATCH 15/27] perf tests: Fix record+probe_libc_inet_pton.sh when event exists Arnaldo Carvalho de Melo
2018-07-25 17:59 ` [PATCH 16/27] tools include: Grab copies of arm64 dependent unistd.h files Arnaldo Carvalho de Melo
2018-07-25 17:59 ` [PATCH 17/27] perf arm64: Generate system call table from asm/unistd.h Arnaldo Carvalho de Melo
2018-07-25 17:59 ` [PATCH 18/27] perf trace arm64: Use generated syscall table Arnaldo Carvalho de Melo
2018-07-25 17:59 ` [PATCH 19/27] perf script: Show correct offsets for DWARF-based unwinding Arnaldo Carvalho de Melo
2018-07-25 17:59 ` [PATCH 20/27] perf tools: Synthesize GROUP_DESC feature in pipe mode Arnaldo Carvalho de Melo
2018-07-25 17:59 ` [PATCH 21/27] perf machine: Add threads__get_last_match function Arnaldo Carvalho de Melo
2018-07-25 17:59 ` [PATCH 22/27] perf machine: Add threads__set_last_match function Arnaldo Carvalho de Melo
2018-07-25 17:59 ` [PATCH 23/27] perf machine: Use last_match threads cache only in single thread mode Arnaldo Carvalho de Melo
2018-07-25 17:59 ` [PATCH 24/27] perf tools: Fix struct comm_str removal crash Arnaldo Carvalho de Melo
2018-07-25 17:59 ` [PATCH 25/27] perf tools: Use perf_evsel__match instead of open coded equivalent Arnaldo Carvalho de Melo
2018-07-25 18:00 ` [PATCH 26/27] perf stat: Get rid of extra clock display function Arnaldo Carvalho de Melo
2018-07-25 18:00 ` [PATCH 27/27] perf test: Fix subtest number when showing results Arnaldo Carvalho de Melo
2018-07-25 20:34 ` [GIT PULL 00/27] perf/core improvements and fixes Ingo Molnar

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