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Andi Kleen 90b10f47c0 perf script: Support relative time
When comparing time stamps in 'perf script' traces it can be annoying to
work with the full perf time stamps.

Add a --reltime option that displays time stamps relative to the trace
start to make it easier to read the traces.

Note: not currently supported for --time. Report an error in this
case.

Before:

  % perf script
      swapper 0 [000] 245402.891216:    1 cycles:ppp: ffffffffa0068814 native_write_msr+0x4 ([kernel.kallsyms])
      swapper 0 [000] 245402.891223:    1 cycles:ppp: ffffffffa0068814 native_write_msr+0x4 ([kernel.kallsyms])
      swapper 0 [000] 245402.891227:    5 cycles:ppp: ffffffffa0068814 native_write_msr+0x4 ([kernel.kallsyms])
      swapper 0 [000] 245402.891231:   41 cycles:ppp: ffffffffa0068816 native_write_msr+0x6 ([kernel.kallsyms])
      swapper 0 [000] 245402.891235:  355 cycles:ppp: ffffffffa000dd51 intel_bts_enable_local+0x21 ([kernel.kallsyms])
      swapper 0 [000] 245402.891239: 3084 cycles:ppp: ffffffffa0a0150a end_repeat_nmi+0x48 ([kernel.kallsyms])

After:

  % perf script --reltime

      swapper 0 [000]     0.000000:    1 cycles:ppp: ffffffffa0068814 native_write_msr+0x4 ([kernel.kallsyms])
      swapper 0 [000]     0.000006:    1 cycles:ppp: ffffffffa0068814 native_write_msr+0x4 ([kernel.kallsyms])
      swapper 0 [000]     0.000010:    5 cycles:ppp: ffffffffa0068814 native_write_msr+0x4 ([kernel.kallsyms])
      swapper 0 [000]     0.000014:   41 cycles:ppp: ffffffffa0068816 native_write_msr+0x6 ([kernel.kallsyms])
      swapper 0 [000]     0.000018:  355 cycles:ppp: ffffffffa000dd51 intel_bts_enable_local+0x21 ([kernel.kallsyms])
      swapper 0 [000]     0.000022: 3084 cycles:ppp: ffffffffa0a0150a end_repeat_nmi+0x48 ([kernel.kallsyms])

Committer notes:

Do not use 'time' as the name of a variable, as this breaks the build on
older glibcs:

  cc1: warnings being treated as errors
  builtin-script.c: In function 'perf_sample__fprintf_start':
  builtin-script.c:691: warning: declaration of 'time' shadows a global declaration
  /usr/include/time.h:187: warning: shadowed declaration is here

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
LPU-Reference: 20190314225002.30108-8-andi@firstfloor.org
Link: https://lkml.kernel.org/n/tip-bpahyi6pr9r399mvihu65fvc@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-03-19 16:52:03 -03:00
arch perf/x86/intel/uncore: Fix client IMC events return huge result 2019-03-09 14:10:31 +01:00
block for-linus-20190215 2019-02-15 09:12:28 -08:00
certs kbuild: remove redundant target cleaning on failure 2019-01-06 09:46:51 +09:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2019-03-05 09:09:55 -08:00
Documentation Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-03-06 08:14:05 -08:00
drivers Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-03-06 07:59:36 -08:00
firmware kbuild: change filechk to surround the given command with { } 2019-01-06 09:46:51 +09:00
fs Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-03-06 08:14:05 -08:00
include Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-03-06 08:14:05 -08:00
init Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-03-06 08:14:05 -08:00
ipc y2038: syscalls: rename y2038 compat syscalls 2019-02-07 00:13:27 +01:00
kernel perf/core: Restore mmap record type correctly 2019-03-11 11:56:02 -03:00
lib Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-03-06 07:59:36 -08:00
LICENSES This is a fairly typical cycle for documentation. There's some welcome 2018-10-24 18:01:11 +01:00
mm Merge branch 'akpm' (patches from Andrew) 2019-03-01 09:04:59 -08:00
net Merge branch 'timers-2038-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-03-05 14:08:26 -08:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2019-03-05 08:26:13 -08:00
scripts Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-03-06 07:17:17 -08:00
security get rid of legacy 'get_ds()' function 2019-03-04 10:50:14 -08:00
sound sound fixes for 5.0 2019-02-20 09:42:52 -08:00
tools perf script: Support relative time 2019-03-19 16:52:03 -03:00
usr user/Makefile: Fix typo and capitalization in comment section 2018-12-11 00:18:03 +09:00
virt Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-03-05 14:49:11 -08:00
.clang-format clang-format: Update .clang-format with the latest for_each macro list 2019-01-19 19:26:06 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support for DT binding schema checks 2018-12-13 09:41:32 -06:00
.mailmap .mailmap: Add Mathieu Othacehe 2019-02-21 11:41:19 +00:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS CREDITS/MAINTAINERS: Retire parisc-linux.org email domain 2019-02-21 20:16:10 +01:00
Kbuild Merge branch 'locking/atomics' into locking/core, to pick up WIP commits 2019-02-11 14:27:05 +01:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-03-06 08:14:05 -08:00
Makefile Linux 5.0 2019-03-03 15:21:29 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

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.