Linux perf integration with the new support for JIT.

Linux perf integration with the new support for JIT.

Difference from --perf-basic-prof:
- correctly attributes samples when code space gets reused (when unused code object dies and a new code objects is allocated at the same place).
- outputs compiled machine code for instruction-level profile.

Just like --perf-basic-prof, the file writer is not synchronized (even worse, there is a per-isolate file handle), so we will run into trouble with multiple isolates. However, this patch is still an improvement on --perf-basic-prof, and it should be fine to replace ll-prof.

The patch also introduces experimental support for debug info, but it does not seem to be picked by the perf tool.

Usage:

You need the perf tool from Linux kernel >4.5. Then run:

$ perf record -k mono d8 --perf-prof <your JS file>
$ perf inject -j -i perf.data -o perf.data.jitted
$ perf report -i perf.data.jitted

Some explanations:
The "-k mono" switch from "perf record" tells the perf tool to use the monotonic clock for perf sample timestamping. The "perf inject -j" command injects the collected code events into the perf data file, writing the output into perf.data.jitted. The perf report command then creates the report.

Committed: https://crrev.com/82e95f597b3563e3c1947d760ba138f67d45bf6a
Cr-Commit-Position: refs/heads/master@{#35091}

[Jarin, 2016-03-27 18:30:42]

Description was changed from

==========
Linux perf integration with the new support for JIT (WIP).

Difference from --perf-basic-prof:
- correctly attributes samples when code space gets reused (by GC).
- outputs compiled machine code for instruction-level profile.
- experimental support for debug info.
==========

to

==========
Linux perf integration with the new support for JIT.

Difference from --perf-basic-prof:
- correctly attributes samples when code space gets reused (when unused code
object dies and a new code objects is allocated at the same place).
- outputs compiled machine code for instruction-level profile.

This also introduces experimental support for debug info, but it does not seem
to be picked by the perf tool.
==========

[Jarin, 2016-03-27 18:30:42]

jarin@chromium.org changed reviewers:
+ bmeurer@chromium.org, jochen@chromium.org

[Jarin, 2016-03-27 18:32:19]

Could you take a look, please?

[Jarin, 2016-03-27 18:35:49]

Description was changed from

==========
Linux perf integration with the new support for JIT.

Difference from --perf-basic-prof:
- correctly attributes samples when code space gets reused (when unused code
object dies and a new code objects is allocated at the same place).
- outputs compiled machine code for instruction-level profile.

This also introduces experimental support for debug info, but it does not seem
to be picked by the perf tool.
==========

to

==========
Linux perf integration with the new support for JIT.

Difference from --perf-basic-prof:
- correctly attributes samples when code space gets reused (when unused code
object dies and a new code objects is allocated at the same place).
- outputs compiled machine code for instruction-level profile.

This also introduces experimental support for debug info, but it does not seem
to be picked by the perf tool.

Usage:

You need the perf tool from Linux kernel >4.5. Then run:

$ perf record -k mono d8 --perf-prof <your JS file>
$ perf inject -j -i perf.data -o perf.data.jitted
$ perf report -i perf.data.jitted
==========

[Jarin, 2016-03-27 18:38:58]

Description was changed from

==========
Linux perf integration with the new support for JIT.

Difference from --perf-basic-prof:
- correctly attributes samples when code space gets reused (when unused code
object dies and a new code objects is allocated at the same place).
- outputs compiled machine code for instruction-level profile.

This also introduces experimental support for debug info, but it does not seem
to be picked by the perf tool.

Usage:

You need the perf tool from Linux kernel >4.5. Then run:

$ perf record -k mono d8 --perf-prof <your JS file>
$ perf inject -j -i perf.data -o perf.data.jitted
$ perf report -i perf.data.jitted
==========

to

==========
Linux perf integration with the new support for JIT.

Difference from --perf-basic-prof:
- correctly attributes samples when code space gets reused (when unused code
object dies and a new code objects is allocated at the same place).
- outputs compiled machine code for instruction-level profile.

This also introduces experimental support for debug info, but it does not seem
to be picked by the perf tool.

Usage:

You need the perf tool from Linux kernel >4.5. Then run:

$ perf record -k mono d8 --perf-prof <your JS file>
$ perf inject -j -i perf.data -o perf.data.jitted
$ perf report -i perf.data.jitted

Some explanations:
The "-k mono" switch from "perf record" tells the perf tool to use the monotonic
clock for perf sample timestamping. The "perf inject -j" command injects the
collected code events into the perf data file, writing the output into
perf.data.jitted. The perf report command then creates the report.
==========

[Jarin, 2016-03-27 18:47:20]

Description was changed from

==========
Linux perf integration with the new support for JIT.

Difference from --perf-basic-prof:
- correctly attributes samples when code space gets reused (when unused code
object dies and a new code objects is allocated at the same place).
- outputs compiled machine code for instruction-level profile.

This also introduces experimental support for debug info, but it does not seem
to be picked by the perf tool.

Usage:

You need the perf tool from Linux kernel >4.5. Then run:

$ perf record -k mono d8 --perf-prof <your JS file>
$ perf inject -j -i perf.data -o perf.data.jitted
$ perf report -i perf.data.jitted

Some explanations:
The "-k mono" switch from "perf record" tells the perf tool to use the monotonic
clock for perf sample timestamping. The "perf inject -j" command injects the
collected code events into the perf data file, writing the output into
perf.data.jitted. The perf report command then creates the report.
==========

to

==========
Linux perf integration with the new support for JIT.

Difference from --perf-basic-prof:
- correctly attributes samples when code space gets reused (when unused code
object dies and a new code objects is allocated at the same place).
- outputs compiled machine code for instruction-level profile.

Just like --perf-basic-prof, the file writer is not synchronized (even worse,
there is a per-isolate file handle), so we will run into trouble with multiple
isolates. However, this patch is still an improvement on --perf-basic-prof, and
it should be fine to replace ll-prof.

The patch also introduces experimental support for debug info, but it does not
seem to be picked by the perf tool.

Usage:

You need the perf tool from Linux kernel >4.5. Then run:

$ perf record -k mono d8 --perf-prof <your JS file>
$ perf inject -j -i perf.data -o perf.data.jitted
$ perf report -i perf.data.jitted

Some explanations:
The "-k mono" switch from "perf record" tells the perf tool to use the monotonic
clock for perf sample timestamping. The "perf inject -j" command injects the
collected code events into the perf data file, writing the output into
perf.data.jitted. The perf report command then creates the report.
==========

[Benedikt Meurer, 2016-03-28 16:52:05]

LGTM.

[ofrobots, 2016-03-28 20:20:39]

ofrobots@google.com changed reviewers:
+ ofrobots@google.com

[ofrobots, 2016-03-28 20:20:40]

https://codereview.chromium.org/1809203007/diff/20001/src/perf-jit.cc
File src/perf-jit.cc (right):

https://codereview.chromium.org/1809203007/diff/20001/src/perf-jit.cc#newcode158
src/perf-jit.cc:158: void PerfJitLogger::LogRecordedBuffer(AbstractCode*
abstract_code,
Drive-by comment: Similar to PerfBasicLogger, it would be nice to respect
FLAG_perf_basic_prof_only_functions here. That flag is useful on long running
code (e.g. Node.js servers) where the log entries for stubs etc. may cause the
log file to grow in an unbounded fashion.

[Jarin, 2016-03-29 05:42:00]

On 2016/03/28 20:20:40, ofrobots wrote:
> https://codereview.chromium.org/1809203007/diff/20001/src/perf-jit.cc
> File src/perf-jit.cc (right):
> 
>
https://codereview.chromium.org/1809203007/diff/20001/src/perf-jit.cc#newcode158
> src/perf-jit.cc:158: void PerfJitLogger::LogRecordedBuffer(AbstractCode*
> abstract_code,
> Drive-by comment: Similar to PerfBasicLogger, it would be nice to respect
> FLAG_perf_basic_prof_only_functions here. That flag is useful on long running
> code (e.g. Node.js servers) where the log entries for stubs etc. may cause the
> log file to grow in an unbounded fashion.

Good idea, done in patch set #3. Thanks!

[Jarin, 2016-03-29 06:14:10]

The CQ bit was checked by jarin@chromium.org

[Jarin, 2016-03-29 06:14:10]

The patchset sent to the CQ was uploaded after l-g-t-m from bmeurer@chromium.org
Link to the patchset: https://codereview.chromium.org/1809203007/#ps60001
(title: "Fixes")

[commit-bot: I haz the power, 2016-03-29 06:14:20]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1809203007/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1809203007/60001

[commit-bot: I haz the power, 2016-03-29 06:24:02]

Description was changed from

==========
Linux perf integration with the new support for JIT.

Difference from --perf-basic-prof:
- correctly attributes samples when code space gets reused (when unused code
object dies and a new code objects is allocated at the same place).
- outputs compiled machine code for instruction-level profile.

Just like --perf-basic-prof, the file writer is not synchronized (even worse,
there is a per-isolate file handle), so we will run into trouble with multiple
isolates. However, this patch is still an improvement on --perf-basic-prof, and
it should be fine to replace ll-prof.

The patch also introduces experimental support for debug info, but it does not
seem to be picked by the perf tool.

Usage:

You need the perf tool from Linux kernel >4.5. Then run:

$ perf record -k mono d8 --perf-prof <your JS file>
$ perf inject -j -i perf.data -o perf.data.jitted
$ perf report -i perf.data.jitted

Some explanations:
The "-k mono" switch from "perf record" tells the perf tool to use the monotonic
clock for perf sample timestamping. The "perf inject -j" command injects the
collected code events into the perf data file, writing the output into
perf.data.jitted. The perf report command then creates the report.
==========

to

==========
Linux perf integration with the new support for JIT.

Difference from --perf-basic-prof:
- correctly attributes samples when code space gets reused (when unused code
object dies and a new code objects is allocated at the same place).
- outputs compiled machine code for instruction-level profile.

Just like --perf-basic-prof, the file writer is not synchronized (even worse,
there is a per-isolate file handle), so we will run into trouble with multiple
isolates. However, this patch is still an improvement on --perf-basic-prof, and
it should be fine to replace ll-prof.

The patch also introduces experimental support for debug info, but it does not
seem to be picked by the perf tool.

Usage:

You need the perf tool from Linux kernel >4.5. Then run:

$ perf record -k mono d8 --perf-prof <your JS file>
$ perf inject -j -i perf.data -o perf.data.jitted
$ perf report -i perf.data.jitted

Some explanations:
The "-k mono" switch from "perf record" tells the perf tool to use the monotonic
clock for perf sample timestamping. The "perf inject -j" command injects the
collected code events into the perf data file, writing the output into
perf.data.jitted. The perf report command then creates the report.
==========

[commit-bot: I haz the power, 2016-03-29 06:24:03]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2016-03-29 06:25:40]

Description was changed from

==========
Linux perf integration with the new support for JIT.

Difference from --perf-basic-prof:
- correctly attributes samples when code space gets reused (when unused code
object dies and a new code objects is allocated at the same place).
- outputs compiled machine code for instruction-level profile.

Just like --perf-basic-prof, the file writer is not synchronized (even worse,
there is a per-isolate file handle), so we will run into trouble with multiple
isolates. However, this patch is still an improvement on --perf-basic-prof, and
it should be fine to replace ll-prof.

The patch also introduces experimental support for debug info, but it does not
seem to be picked by the perf tool.

Usage:

You need the perf tool from Linux kernel >4.5. Then run:

$ perf record -k mono d8 --perf-prof <your JS file>
$ perf inject -j -i perf.data -o perf.data.jitted
$ perf report -i perf.data.jitted

Some explanations:
The "-k mono" switch from "perf record" tells the perf tool to use the monotonic
clock for perf sample timestamping. The "perf inject -j" command injects the
collected code events into the perf data file, writing the output into
perf.data.jitted. The perf report command then creates the report.
==========

to

==========
Linux perf integration with the new support for JIT.

Difference from --perf-basic-prof:
- correctly attributes samples when code space gets reused (when unused code
object dies and a new code objects is allocated at the same place).
- outputs compiled machine code for instruction-level profile.

Just like --perf-basic-prof, the file writer is not synchronized (even worse,
there is a per-isolate file handle), so we will run into trouble with multiple
isolates. However, this patch is still an improvement on --perf-basic-prof, and
it should be fine to replace ll-prof.

The patch also introduces experimental support for debug info, but it does not
seem to be picked by the perf tool.

Usage:

You need the perf tool from Linux kernel >4.5. Then run:

$ perf record -k mono d8 --perf-prof <your JS file>
$ perf inject -j -i perf.data -o perf.data.jitted
$ perf report -i perf.data.jitted

Some explanations:
The "-k mono" switch from "perf record" tells the perf tool to use the monotonic
clock for perf sample timestamping. The "perf inject -j" command injects the
collected code events into the perf data file, writing the output into
perf.data.jitted. The perf report command then creates the report.

Committed: https://crrev.com/82e95f597b3563e3c1947d760ba138f67d45bf6a
Cr-Commit-Position: refs/heads/master@{#35091}
==========

[commit-bot: I haz the power, 2016-03-29 06:25:41]

Patchset 4 (id:??) landed as
https://crrev.com/82e95f597b3563e3c1947d760ba138f67d45bf6a
Cr-Commit-Position: refs/heads/master@{#35091}