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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2026-09-22 09:34:56 +02:00
Jin Yao
b40982e846
When we use perf report interactive annotate view, we can see
the position of jump arrow is not correct. For example,
1. perf record -b ...
2. perf report
3. In interactive mode, select Annotate 'function'
Percent│ IPC Cycle
│ if (flag)
1.37 │0.4┌── 1 ↓ je 82
│ │ x += x / y + y / x;
0.00 │0.4│ 1310 movsd (%rsp),%xmm0
0.00 │0.4│ 565 movsd 0x8(%rsp),%xmm4
│0.4│ movsd 0x8(%rsp),%xmm1
│0.4│ movsd (%rsp),%xmm3
│0.4│ divsd %xmm4,%xmm0
0.00 │0.4│ 579 divsd %xmm3,%xmm1
│0.4│ movsd (%rsp),%xmm2
│0.4│ addsd %xmm1,%xmm0
│0.4│ addsd %xmm2,%xmm0
0.00 │0.4│ movsd %xmm0,(%rsp)
│ │ volatile double x = 1212121212, y = 121212;
│ │
│ │ s_randseed = time(0);
│ │ srand(s_randseed);
│ │
│ │ for (i = 0; i < 2000000000; i++) {
1.37 │0.4└─→ 82: sub $0x1,%ebx
28.21 │0.48 17 ↑ jne 38
The jump arrow in above example is not correct. It should add the
width of IPC and Cycle.
With this patch, the result is:
Percent│ IPC Cycle
│ if (flag)
1.37 │0.48 1 ┌──je 82
│ │ x += x / y + y / x;
0.00 │0.48 1310 │ movsd (%rsp),%xmm0
0.00 │0.48 565 │ movsd 0x8(%rsp),%xmm4
│0.48 │ movsd 0x8(%rsp),%xmm1
│0.48 │ movsd (%rsp),%xmm3
│0.48 │ divsd %xmm4,%xmm0
0.00 │0.48 579 │ divsd %xmm3,%xmm1
│0.48 │ movsd (%rsp),%xmm2
│0.48 │ addsd %xmm1,%xmm0
│0.48 │ addsd %xmm2,%xmm0
0.00 │0.48 │ movsd %xmm0,(%rsp)
│ │ volatile double x = 1212121212, y = 121212;
│ │
│ │ s_randseed = time(0);
│ │ srand(s_randseed);
│ │
│ │ for (i = 0; i < 2000000000; i++) {
1.37 │0.48 82:└─→sub $0x1,%ebx
28.21 │0.48 17 ↑ jne 38
Committer notes:
Please note that only from LBRv5 (according to Jiri) onwards, i.e. >=
Skylake is that we'll have the cycles counts in each branch record
entry, so to see the Cycles and IPC columns, and be able to test this
patch, one need a capable hardware.
While applying this I first tested it on a Broadwell class machine and
couldn't get those columns, will add code to the annotate browser to
warn the user about that, i.e. you have branch records, but no cycles,
use a more recent hardware to get the cycles and IPC columns.
Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jin Yao <yao.jin@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1517223473-14750-1-git-send-email-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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.