linux-toradex.git/tools/perf/builtin-annotate.c, branch v4.9.116

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 --stdio-color to setup the color output mode selection

2016-07-12T03:00:39+00:00

'perf annotate --stdio' will colorize entries with most hits and
possibly some other aspects of its output, but those colors gets
suppressed if we redirect the output to a non-tty, allow keeping the
colors by adding a new option, --stdio-color, now this use case will
also output escape sequences for colors:

  $ perf annotate --stdio-color | more

Based-on-a-patch-by: Peter Zijlstra 
Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Wang Nan 
Link: http://lkml.kernel.org/n/tip-sjrnixani5pg6qez640gaxhf@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf evlist: Rename for_each() macros to for_each_entry()

2016-06-23T14:26:15+00:00

To match the semantics for list.h in the kernel, that are used to
implement those macros.

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Milian Wolff 
Cc: Namhyung Kim 
Cc: Taeung Song 
Cc: Wang Nan 
Link: http://lkml.kernel.org/n/tip-qbcjlgj0ffxquxscahbpddi3@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf hists: Rename histsadd_entry to hists__add_entry

2016-06-21T16:18:33+00:00

There's no reason we should suffer the '__' prefix for the base global
function.

Signed-off-by: Jiri Olsa 
Cc: David Ahern 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1465928361-2442-12-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Set buildid dir under symfs when --symfs is provided

2016-05-20T14:43:58+00:00

This patch moves the reference of buildid dir to 'symfs/.debug' and
skips the local buildid dir when '--symfs' is given, so that every
single file opened by perf is relative to symfs directory now.

Signed-off-by: He Kuang 
Acked-by: David Ahern 
Acked-by: Jiri Olsa 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: Ekaterina Tumanova 
Cc: Josh Poimboeuf 
Cc: Kan Liang 
Cc: Masami Hiramatsu 
Cc: Namhyung Kim 
Cc: Pekka Enberg 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: Sukadev Bhattiprolu 
Cc: Wang Nan 
Link: http://lkml.kernel.org/r/1463658462-85131-2-git-send-email-hekuang@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo

perf machine: Rename perf_event__preprocess_sample to machine__resolve

2016-03-23T15:03:08+00:00

Since we only deal with fields in the passed struct perf_sample move
this method to struct machine, that is where the perf_sample fields
will be resolved to a struct addr_location, i.e. thread, map, symbol,
etc.

Cc: Adrian Hunter 
Cc: Hemant Kumar 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Naveen N. Rao 
Cc: Ravi Bangoria 
Cc: Wang Nan 
Link: http://lkml.kernel.org/n/tip-a1ww2lbm2vbuqsv4p7ilubu9@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf hists: Introduce perf_evsel__output_resort function

2016-02-03T14:13:11+00:00

Adding evsel specific function to sort hists_evsel based hists. The
hists__output_resort can be now used to sort common hists object.

Signed-off-by: Jiri Olsa 
Cc: David Ahern 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1453109064-1026-3-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Pass evlist to setup_sorting()

2016-01-06T23:11:11+00:00

This is a preparation to support dynamic sort keys for tracepoint
events.  Dynamic sort keys can be created for specific fields in trace
events so it needs the event information.

Signed-off-by: Namhyung Kim 
Acked-by: Jiri Olsa 
Cc: Andi Kleen 
Cc: David Ahern 
Cc: Frederic Weisbecker 
Cc: Peter Zijlstra 
Cc: Steven Rostedt 
Cc: Wang Nan 
Link: http://lkml.kernel.org/r/1450804030-29193-5-git-send-email-namhyung@kernel.org
[ Moving the evlist creation earlier in top was split to a previous patch ]
Signed-off-by: Arnaldo Carvalho de Melo

perf hist: Pass struct sample to histsadd_entry()

2016-01-06T23:11:10+00:00

This is a preparation to add more info into the hist_entry.  Also it
already passes too many argument, so passing sample directly will reduce
the overhead of the function call.

Signed-off-by: Namhyung Kim 
Acked-by: Jiri Olsa 
Cc: Andi Kleen 
Cc: David Ahern 
Cc: Frederic Weisbecker 
Cc: Peter Zijlstra 
Cc: Steven Rostedt 
Cc: Wang Nan 
Link: http://lkml.kernel.org/r/1450804030-29193-2-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo