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Milian Wolff 9856240ad3 perf callchain: Compare symbol name for inlined frames when matching
The fake symbols we create for inlined frames will represent different
functions but can use the symbol start address. This leads to issues
when different inline branches all lead to the same function.

Before:
~~~~~
$ perf report -s sym -i perf.inlining.data --inline --stdio -g function
...
             --38.86%--_start
                       __libc_start_main
                       main
                       |
                        --37.57%--std::norm<double> (inlined)
                                  std::_Norm_helper<true>::_S_do_it<double> (inlined)
                                  |
                                   --36.36%--std::abs<double> (inlined)
                                             std::__complex_abs (inlined)
                                             |
                                              --12.24%--std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul>::operator() (inlined)
                                                        std::__detail::__mod<unsigned long, 2147483647ul, 16807ul, 0ul> (inlined)
                                                        std::__detail::_Mod<unsigned long, 2147483647ul, 16807ul, 0ul, true, true>::__calc (inlined)
~~~~~

Note that this backtrace representation is completely bogus.
Complex abs does not call the linear congruential engine! It
is just a side-effect of a longer inlined stack being appended
to a shorter, different inlined stack, both of which originate
in the same function (main).

This patch fixes the issue:

~~~~~
$ perf report -s sym -i perf.inlining.data --inline --stdio -g function
...
             --38.86%--_start
                       __libc_start_main
                       main
                       |
                       |--35.59%--std::uniform_real_distribution<double>::operator()<std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul> > (inlined)
                       |          std::uniform_real_distribution<double>::operator()<std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul> > (inlined)
                       |          |
                       |           --34.37%--std::__detail::_Adaptor<std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul>, double>::operator() (inlined)
                       |                     std::generate_canonical<double, 53ul, std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul> > (inlined)
                       |                     |
                       |                      --12.24%--std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul>::operator() (inlined)
                       |                                std::__detail::__mod<unsigned long, 2147483647ul, 16807ul, 0ul> (inlined)
                       |                                std::__detail::_Mod<unsigned long, 2147483647ul, 16807ul, 0ul, true, true>::__calc (inlined)
                       |
                        --1.99%--std::norm<double> (inlined)
                                  std::_Norm_helper<true>::_S_do_it<double> (inlined)
                                  std::abs<double> (inlined)
                                  std::__complex_abs (inlined)
~~~~~

Signed-off-by: Milian Wolff <milian.wolff@kdab.com>
Reviewed-by: Jiri Olsa <jolsa@redhat.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Yao Jin <yao.jin@linux.intel.com>
Link: http://lkml.kernel.org/r/20171009203310.17362-10-milian.wolff@kdab.com
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
[ Fix up conflict with c1fbc0cf81 ("perf callchain: Compare dsos (as well) for CCKEY_FUNCTION"), remove unneeded hunk ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2017-10-24 09:59:56 -03:00
arch Merge branch 'perf/urgent' into perf/core, to pick up fixes 2017-10-20 11:02:05 +02:00
block bio_copy_user_iov(): don't ignore ->iov_offset 2017-10-10 23:55:14 -04:00
certs modsign: add markers to endif-statements in certs/Makefile 2017-07-14 11:01:37 +10:00
crypto crypto: shash - Fix zero-length shash ahash digest crash 2017-10-11 00:34:07 +08:00
Documentation kprobes/docs: Remove jprobes related documents 2017-10-20 11:02:55 +02:00
drivers lkdtm, kprobes: Convert from jprobes to kprobes 2017-10-23 13:52:45 +02:00
firmware firmware: Restore support for built-in firmware 2017-09-16 10:58:48 -07:00
fs membarrier: Provide register expedited private command 2017-10-19 22:13:40 -04:00
include kprobes: Disable the jprobes APIs 2017-10-20 11:02:29 +02:00
init Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-09-14 18:54:01 -07:00
ipc fix a typo in put_compat_shm_info() 2017-09-25 20:41:46 -04:00
kernel kprobes: Disable the jprobes test code 2017-10-20 11:02:54 +02:00
lib Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-10-14 15:14:20 -04:00
mm mm, swap: use page-cluster as max window of VMA based swap readahead 2017-10-13 16:18:33 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-10-09 16:25:00 -07:00
samples kprobes: Remove the jprobes sample code 2017-10-20 11:02:55 +02:00
scripts scripts/kallsyms.c: ignore symbol type 'n' 2017-10-13 16:18:32 -07:00
security lsm: fix smack_inode_removexattr and xattr_getsecurity memleak 2017-10-04 18:03:15 +11:00
sound ALSA: hda - Fix incorrect TLV callback check introduced during set_fs() removal 2017-10-18 12:27:00 +02:00
tools perf callchain: Compare symbol name for inlined frames when matching 2017-10-24 09:59:56 -03:00
usr ramfs: clarify help text that compression applies to ramfs as well as legacy ramdisk. 2017-07-06 16:24:30 -07:00
virt Revert "KVM: Don't accept obviously wrong gsi values via KVM_IRQFD" 2017-09-19 08:37:17 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap Update James Hogan's email address 2017-10-04 17:11:53 -07:00
COPYING
CREDITS selinux/stable-4.14 PR 20170831 2017-09-12 13:21:00 -07:00
Kbuild kbuild: Consolidate header generation from ASM offset information 2017-04-13 05:43:37 +09:00
Kconfig
MAINTAINERS perf/urgent fixes: 2017-10-20 09:14:06 +02:00
Makefile Linux 4.14-rc5 2017-10-15 21:01:12 -04:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.