Profiling process topology

Profiling process topology.

Changes the --memlog command line switch to launch the browser, which then in turn launches the profiling process as a child (previously it was the reverse). Creates a ProfilingProcessHost in the browser process and hooks it up as necessary.

This code is still a work in progress and doesn't necessarily run properly. The system still uses Windows named pipes and requires --no-sandbox.

Review-Url: https://codereview.chromium.org/2948283002
Cr-Commit-Position: refs/heads/master@{#483482}
Committed: https://chromium.googlesource.com/chromium/src/+/8d903369ede3f897ab94cb0219ec125cfed88c7d

[brettw, 2017-06-27 22:22:43]

The CQ bit was checked by brettw@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-06-27 22:23:03]

Dry run: CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-06-27 23:43:32]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-06-27 23:43:32]

Dry run: This issue passed the CQ dry run.

[brettw, 2017-06-29 18:08:09]

No idea

[brettw, 2017-06-29 18:09:23]

Patchset #4 (id:60001) has been deleted

[brettw, 2017-06-29 18:09:31]

brettw@chromium.org changed reviewers:
+ ajwong@chromium.org

[brettw, 2017-06-29 18:10:50]

Description was changed from

==========
Profiling process topology

BUG=
==========

to

==========
Profiling process topology.

Changes the --memlog command line switch to launch the browser, which then in
turn launches the profiling process as a child (previously it was the reverse).

Creates a ProfilingProcessHost in the browser process and hooks it up as
necessary. The system still uses Windows named pipes and requires --no-sandbox.
==========

[awong, 2017-06-29 18:13:17]

On 2017/06/29 18:09:31, brettw wrote:

First comment: Can you fix the CL description to be more descriptive and to
express that this code is not fully vetted or trustable?

[brettw, 2017-06-29 18:18:49]

Description was changed from

==========
Profiling process topology.

Changes the --memlog command line switch to launch the browser, which then in
turn launches the profiling process as a child (previously it was the reverse).

Creates a ProfilingProcessHost in the browser process and hooks it up as
necessary. The system still uses Windows named pipes and requires --no-sandbox.
==========

to

==========
Profiling process topology.

Changes the --memlog command line switch to launch the browser, which then in
turn launches the profiling process as a child (previously it was the reverse).
Creates a ProfilingProcessHost in the browser process and hooks it up as
necessary.

This code is still a work in progress and doesn't necessarily run properly. The
system still uses Windows named pipes and requires --no-sandbox.
==========

[brettw, 2017-06-29 18:18:59]

On 2017/06/29 18:13:17, awong wrote:
> On 2017/06/29 18:09:31, brettw wrote:
> 
> First comment: Can you fix the CL description to be more descriptive and to
> express that this code is not fully vetted or trustable?

done

[awong, 2017-06-29 18:39:32]

LGTM with documentation nits.

https://codereview.chromium.org/2948283002/diff/40001/chrome/browser/profilin...
File chrome/browser/profiling_host/profiling_process_host.cc (right):

https://codereview.chromium.org/2948283002/diff/40001/chrome/browser/profilin...
chrome/browser/profiling_host/profiling_process_host.cc:20:
ProfilingProcessHost* pph_singleton = nullptr;
prefix with a g_?

https://codereview.chromium.org/2948283002/diff/40001/chrome/browser/profilin...
chrome/browser/profiling_host/profiling_process_host.cc:68:
ProfilingProcessHost* ProfilingProcessHost::Get() {
Why bother with the Get() versus EnsureStarted()?  Is it just to optimize a
fast-path access (no thread-lock check on the static, no check if IsValid(),
etc)?

https://codereview.chromium.org/2948283002/diff/40001/chrome/browser/profilin...
chrome/browser/profiling_host/profiling_process_host.cc:75: if (!pph_singleton)
Use Get() instead?

https://codereview.chromium.org/2948283002/diff/40001/chrome/browser/profilin...
chrome/browser/profiling_host/profiling_process_host.cc:78:
pph_singleton->pipe_id_);
Use Get() instead?

https://codereview.chromium.org/2948283002/diff/40001/chrome/browser/profilin...
chrome/browser/profiling_host/profiling_process_host.cc:85: base::CommandLine
profiling_cmd = MakeProfilingCommandLine(pipe_id_);
Been meaning to ask... are there any security considerations of using Pid as the
pipe_id here?

https://codereview.chromium.org/2948283002/diff/40001/chrome/browser/profilin...
File chrome/browser/profiling_host/profiling_process_host.h (right):

https://codereview.chromium.org/2948283002/diff/40001/chrome/browser/profilin...
chrome/browser/profiling_host/profiling_process_host.h:37: // no profiling
process is launched, null.
null -> nullptr

https://codereview.chromium.org/2948283002/diff/40001/chrome/browser/profilin...
chrome/browser/profiling_host/profiling_process_host.h:42: // currently active.
"Appends necessary switches to a command line for a child process" -> "Appends
necessary switches to a command line for a child process so it can be profiled"

"causse" -> "cause"

"start in the profiling mode currently active" <-- that doesn't parse... can you
reword?

[brettw, 2017-06-29 19:31:12]

https://codereview.chromium.org/2948283002/diff/40001/chrome/browser/profilin...
File chrome/browser/profiling_host/profiling_process_host.cc (right):

https://codereview.chromium.org/2948283002/diff/40001/chrome/browser/profilin...
chrome/browser/profiling_host/profiling_process_host.cc:20:
ProfilingProcessHost* pph_singleton = nullptr;
On 2017/06/29 18:39:31, awong wrote:
> prefix with a g_?

This function is in an anon namespace so is file static. I don't normally treat
these things as "globals".

https://codereview.chromium.org/2948283002/diff/40001/chrome/browser/profilin...
chrome/browser/profiling_host/profiling_process_host.cc:68:
ProfilingProcessHost* ProfilingProcessHost::Get() {
On 2017/06/29 18:39:31, awong wrote:
> Why bother with the Get() versus EnsureStarted()?  Is it just to optimize a
> fast-path access (no thread-lock check on the static, no check if IsValid(),
> etc)?

Some code, like AddSwitchesToChildCmdLine, need to do something with the PPH if
it's running, but don't want querying it to start profiling.

https://codereview.chromium.org/2948283002/diff/40001/chrome/browser/profilin...
chrome/browser/profiling_host/profiling_process_host.cc:75: if (!pph_singleton)
On 2017/06/29 18:39:31, awong wrote:
> Use Get() instead?

Done.

https://codereview.chromium.org/2948283002/diff/40001/chrome/browser/profilin...
chrome/browser/profiling_host/profiling_process_host.cc:85: base::CommandLine
profiling_cmd = MakeProfilingCommandLine(pipe_id_);
On 2017/06/29 18:39:32, awong wrote:
> Been meaning to ask... are there any security considerations of using Pid as
the
> pipe_id here?

I don't know, I will make a note to ask.

[brettw, 2017-06-29 19:32:30]

Review comments

[brettw, 2017-06-29 19:32:31]

The CQ bit was checked by brettw@chromium.org

[brettw, 2017-06-29 19:32:31]

The patchset sent to the CQ was uploaded after l-g-t-m from ajwong@chromium.org
Link to the patchset: https://codereview.chromium.org/2948283002/#ps80001
(title: "Review comments")

[commit-bot: I haz the power, 2017-06-29 19:33:01]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-06-29 20:56:01]

CQ is committing da patch.

Bot data: {"patchset_id": 80001, "attempt_start_ts": 1498764751273410,
"parent_rev": "ef9fb853302ac7f0ec4af00a49613251cd00357d", "commit_rev":
"8d903369ede3f897ab94cb0219ec125cfed88c7d"}

[commit-bot: I haz the power, 2017-06-29 20:56:18]

Description was changed from

==========
Profiling process topology.

Changes the --memlog command line switch to launch the browser, which then in
turn launches the profiling process as a child (previously it was the reverse).
Creates a ProfilingProcessHost in the browser process and hooks it up as
necessary.

This code is still a work in progress and doesn't necessarily run properly. The
system still uses Windows named pipes and requires --no-sandbox.
==========

to

==========
Profiling process topology.

Changes the --memlog command line switch to launch the browser, which then in
turn launches the profiling process as a child (previously it was the reverse).
Creates a ProfilingProcessHost in the browser process and hooks it up as
necessary.

This code is still a work in progress and doesn't necessarily run properly. The
system still uses Windows named pipes and requires --no-sandbox.

Review-Url: https://codereview.chromium.org/2948283002
Cr-Commit-Position: refs/heads/master@{#483482}
Committed:
https://chromium.googlesource.com/chromium/src/+/8d903369ede3f897ab94cb0219ec...
==========

[commit-bot: I haz the power, 2017-06-29 20:56:20]

Committed patchset #4 (id:80001) as
https://chromium.googlesource.com/chromium/src/+/8d903369ede3f897ab94cb0219ec...