linux-toradex.git/tools/perf/util/annotate.h, branch v4.9.16

perf annotate: Pass the symbol's map/dso to the instruction parsers

2016-09-20T15:28:29+00:00

So that things like:

       → callq  0xffffffff993e3230

found while disassembling /proc/kcore can be beautified by later
patches, that will resolve that address to a function, looking it up in
/proc/kallsyms.

Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Chris Riyder 
Cc: David Ahern 
Cc: Hemant Kumar 
Cc: Jiri Olsa 
Cc: Markus Trippelsdorf 
Cc: Masami Hiramatsu 
Cc: Michael Ellerman 
Cc: Namhyung Kim 
Cc: Naveen N. Rao 
Cc: Pawel Moll 
Cc: Peter Zijlstra 
Cc: Ravi Bangoria 
Cc: Russell King 
Cc: Taeung Song 
Cc: Wang Nan 
Link: http://lkml.kernel.org/n/tip-p76myuke4j7gplg54amaklxk@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Add branch stack / basic block

2016-09-08T16:44:03+00:00

I wanted to know the hottest path through a function and figured the
branch-stack (LBR) information should be able to help out with that.

The below uses the branch-stack to create basic blocks and generate
statistics from them.

        from    to              branch_i
        * ----> *
                |
                | block
                v
                * ----> *
                from    to      branch_i+1

The blocks are broken down into non-overlapping ranges, while tracking
if the start of each range is an entry point and/or the end of a range
is a branch.

Each block iterates all ranges it covers (while splitting where required
to exactly match the block) and increments the 'coverage' count.

For the range including the branch we increment the taken counter, as
well as the pred counter if flags.predicted.

Using these number we can find if an instruction:

 - had coverage; given by:

        br->coverage / br->sym->max_coverage

   This metric ensures each symbol has a 100% spot, which reflects the
   observation that each symbol must have a most covered/hottest
   block.

 - is a branch target: br->is_target && br->start == add

 - for targets, how much of a branch's coverages comes from it:

	target->entry / branch->coverage

 - is a branch: br->is_branch && br->end == addr

 - for branches, how often it was taken:

        br->taken / br->coverage

   after all, all execution that didn't take the branch would have
   incremented the coverage and continued onward to a later branch.

 - for branches, how often it was predicted:

        br->pred / br->taken

The coverage percentage is used to color the address and asm sections;
for low (<1%) coverage we use NORMAL (uncolored), indicating that these
instructions are not 'important'. For high coverage (>75%) we color the
address RED.

For each branch, we add an asm comment after the instruction with
information on how often it was taken and predicted.

Output looks like (sans color, which does loose a lot of the
information :/)

$ perf record --branch-filter u,any -e cycles:p ./branches 27
$ perf annotate branches

 Percent |	Source code & Disassembly of branches for cycles:pu (217 samples)
---------------------------------------------------------------------------------
         :	branches():
    0.00 :	  40057a:       push   %rbp
    0.00 :	  40057b:       mov    %rsp,%rbp
    0.00 :	  40057e:       sub    $0x20,%rsp
    0.00 :	  400582:       mov    %rdi,-0x18(%rbp)
    0.00 :	  400586:       mov    %rsi,-0x20(%rbp)
    0.00 :	  40058a:       mov    -0x18(%rbp),%rax
    0.00 :	  40058e:       mov    %rax,-0x10(%rbp)
    0.00 :	  400592:       movq   $0x0,-0x8(%rbp)
    0.00 :	  40059a:       jmpq   400656 
    1.84 :	  40059f:       mov    -0x10(%rbp),%rax	# +100.00%
    3.23 :	  4005a3:       and    $0x1,%eax
    1.84 :	  4005a6:       test   %rax,%rax
    0.00 :	  4005a9:       je     4005bf 	# -54.50% (p:42.00%)
    0.46 :	  4005ab:       mov    0x200bbe(%rip),%rax        # 601170 
   12.90 :	  4005b2:       add    $0x1,%rax
    2.30 :	  4005b6:       mov    %rax,0x200bb3(%rip)        # 601170 
    0.46 :	  4005bd:       jmp    4005d1 	# -100.00% (p:100.00%)
    0.92 :	  4005bf:       mov    0x200baa(%rip),%rax        # 601170 	# +49.54%
   13.82 :	  4005c6:       sub    $0x1,%rax
    0.46 :	  4005ca:       mov    %rax,0x200b9f(%rip)        # 601170 
    2.30 :	  4005d1:       mov    -0x10(%rbp),%rax	# +50.46%
    0.46 :	  4005d5:       mov    %rax,%rdi
    0.46 :	  4005d8:       callq  400526 	# -100.00% (p:100.00%)
    0.00 :	  4005dd:       mov    %rax,-0x10(%rbp)	# +100.00%
    0.92 :	  4005e1:       mov    -0x18(%rbp),%rax
    0.00 :	  4005e5:       and    $0x1,%eax
    0.00 :	  4005e8:       test   %rax,%rax
    0.00 :	  4005eb:       je     4005ff 	# -100.00% (p:100.00%)
    0.00 :	  4005ed:       mov    0x200b7c(%rip),%rax        # 601170 
    0.00 :	  4005f4:       shr    $0x2,%rax
    0.00 :	  4005f8:       mov    %rax,0x200b71(%rip)        # 601170 
    0.00 :	  4005ff:       mov    -0x10(%rbp),%rax	# +100.00%
    7.37 :	  400603:       and    $0x1,%eax
    3.69 :	  400606:       test   %rax,%rax
    0.00 :	  400609:       jne    400612 	# -59.25% (p:42.99%)
    1.84 :	  40060b:       mov    $0x1,%eax
   14.29 :	  400610:       jmp    400617 	# -100.00% (p:100.00%)
    1.38 :	  400612:       mov    $0x0,%eax	# +57.65%
   10.14 :	  400617:       test   %al,%al	# +42.35%
    0.00 :	  400619:       je     40062f 	# -57.65% (p:100.00%)
    0.46 :	  40061b:       mov    0x200b4e(%rip),%rax        # 601170 
    2.76 :	  400622:       sub    $0x1,%rax
    0.00 :	  400626:       mov    %rax,0x200b43(%rip)        # 601170 
    0.46 :	  40062d:       jmp    400641 	# -100.00% (p:100.00%)
    0.92 :	  40062f:       mov    0x200b3a(%rip),%rax        # 601170 	# +56.13%
    2.30 :	  400636:       add    $0x1,%rax
    0.92 :	  40063a:       mov    %rax,0x200b2f(%rip)        # 601170 
    0.92 :	  400641:       mov    -0x10(%rbp),%rax	# +43.87%
    2.30 :	  400645:       mov    %rax,%rdi
    0.00 :	  400648:       callq  400526 	# -100.00% (p:100.00%)
    0.00 :	  40064d:       mov    %rax,-0x10(%rbp)	# +100.00%
    1.84 :	  400651:       addq   $0x1,-0x8(%rbp)
    0.92 :	  400656:       mov    -0x8(%rbp),%rax
    5.07 :	  40065a:       cmp    -0x20(%rbp),%rax
    0.00 :	  40065e:       jb     40059f 	# -100.00% (p:100.00%)
    0.00 :	  400664:       nop
    0.00 :	  400665:       leaveq
    0.00 :	  400666:       retq

(Note: the --branch-filter u,any was used to avoid spurious target and
branch points due to interrupts/faults, they show up as very small -/+
annotations on 'weird' locations)

Committer note:

Please take a look at:

  http://vger.kernel.org/~acme/perf/annotate_basic_blocks.png

To see the colors.

Signed-off-by: Peter Zijlstra (Intel) 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: Anshuman Khandual 
Cc: David Carrillo-Cisneros 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Linus Torvalds 
Cc: Namhyung Kim 
Cc: Stephane Eranian 
[ Moved sym->max_coverage to 'struct annotate', aka symbol__annotate(sym) ]
Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Initialize the priv are in symbol__new()

2016-08-30T13:56:34+00:00

We need to initializa some fields (right now just a mutex) when we
allocate the per symbol annotation struct, so do it at the symbol
constructor instead of (ab)using the filter mechanism for that.

This way we remove one of the few cases we have for that symbol filter,
which will eventually led to removing it.

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Wang Nan 
Link: http://lkml.kernel.org/n/tip-cvz34avlz1lez888lob95390@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Introduce strerror for handling symbol__disassemble() errors

2016-08-01T21:18:16+00:00

We were just using pr_error() which makes it difficult for non stdio UIs
to provide errors using its widgets, as they need to somehow catch what
was passed to pr_error().

Fix it by introducing a __strerror() interface like the ones used
elsewhere, for instance target__strerror().

This is just the initial step, more work will be done, but first some
error handling bugs noticed while working on this need to be dealt with.

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Wang Nan 
Link: http://lkml.kernel.org/n/tip-dgd22zl2xg7x4vcnoa83jxfb@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Rename symbolannotate() to symboldisassemble()

2016-08-01T20:06:46+00:00

This function will not annotate anything, it will just disassembly the
given map->dso and symbol.

It currently does this by parsing the output of 'objdump --disassemble',
but this could conceivably be done using a library or an offshot of
the kernel's instruction decoder (arch/x86/lib/inat.c), etc.

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Wang Nan 
Link: http://lkml.kernel.org/n/tip-2xpfl4bfnrd6x584b390qok7@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Generalize handling of 'ret' instructions

2016-06-27T17:25:05+00:00

Introduce helper to detect 'ret' instructions and use the same in the TUI.
A helper is needed since some architectures such as powerpc have more
than one return instruction.

Signed-off-by: Naveen N. Rao 
Cc: Ananth N Mavinakayanahalli 
Cc: Anton Blanchard 
Cc: Daniel Axtens 
Cc: Michael Ellerman 
Link: http://lkml.kernel.org/r/1466769240-12376-5-git-send-email-ravi.bangoria@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Remove unused hist_entry__annotate function

2016-06-27T13:58:50+00:00

hist_entry__annotate looks part of API but I don't find any caller
of this function. Removing it.

Signed-off-by: Ravi Bangoria 
Cc: Ananth N Mavinakayanahalli 
Cc: Anton Blanchard 
Cc: Daniel Axtens 
Cc: Michael Ellerman 
Link: http://lkml.kernel.org/r/1466769240-12376-2-git-send-email-ravi.bangoria@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Remove misplaced __maybe_unused

2016-03-23T15:03:04+00:00

All over the tree.

Cc: David Ahern 
cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Ravi Bangoria 
Link: http://lkml.kernel.org/n/tip-8nzhnokxyp8y4v7gf0j00oyb@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Fix sizeof_sym_hist overflow issue

2015-10-05T19:15:38+00:00

The annotated_source::sizeof_sym_hist could easily overflow int size,
resulting in crash in __symbol__inc_addr_samples.

Changing its type int size_t as was probably intended from beginning
based on the initialization code in symbol__alloc_hist.

Signed-off-by: Jiri Olsa 
Cc: David Ahern 
Cc: Don Zickus 
Cc: Kan Liang 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1444068369-20978-4-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Compute IPC and basic block cycles

2015-08-06T19:36:12+00:00

Compute the IPC and the basic block cycles for the annotate display.

IPC is computed by counting the instructions, and then dividing the
accounted cycles by that count.

The actual IPC computation can only be done at annotate time, because we
need to parse the objdump output first to know the number of
instructions in the basic block.

The cycles/IPC are also put into the perf function annotation so that
the display code can show them.

Again basic block overlaps are not handled, with the longest winning,
but there are some heuristics to hide the IPC when the longest is not
the most common.

v2: Compute IPC correctly.

Signed-off-by: Andi Kleen 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Link: http://lkml.kernel.org/r/1437233094-12844-6-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo