Minor updates to frontend perf tool: warm up & derive .packages directly.

Minor updates to frontend perf tool: warm up & derive .packages directly.

BUG=
R=paulberry@google.com

Committed: https://github.com/dart-lang/sdk/commit/e79c120827538abbc5778a442b58cb47c968ec6a

[Siggi Cherem (dart-lang), 2016-10-10 18:45:22]

sigmund@google.com changed reviewers:
+ paulberry@google.com

[Paul Berry, 2016-10-10 19:20:40]

https://codereview.chromium.org/2405943002/diff/1/pkg/analyzer_cli/tool/perf....
File pkg/analyzer_cli/tool/perf.dart (right):

https://codereview.chromium.org/2405943002/diff/1/pkg/analyzer_cli/tool/perf....
pkg/analyzer_cli/tool/perf.dart:39: print('usage: perf.dart <bench-id>
<entry.dart>');
Consider using the args package so that we can have a more stable command-line
API to this tool.

https://codereview.chromium.org/2405943002/diff/1/pkg/analyzer_cli/tool/perf....
pkg/analyzer_cli/tool/perf.dart:52: for (int i = 0; i < 10; i++)
scanFiles(files);
It looks like the way you're doing the warmup is to run the operation 10x and
take the sum of all of runs.  What I'd recommend doing instead is:  Run the
operation 10x, then start a timer, then run 10x more, then stop the timer.  This
allows the warmup time to be completely excluded from the benchmark, rather than
merely diluted.

https://codereview.chromium.org/2405943002/diff/1/pkg/analyzer_cli/tool/perf....
pkg/analyzer_cli/tool/perf.dart:56: for (int i = 0; i < 10; i++)
parseFiles(files);
Similar comment here.

[Siggi Cherem (dart-lang), 2016-10-10 19:30:02]

thanks Paul!

https://codereview.chromium.org/2405943002/diff/1/pkg/analyzer_cli/tool/perf....
File pkg/analyzer_cli/tool/perf.dart (right):

https://codereview.chromium.org/2405943002/diff/1/pkg/analyzer_cli/tool/perf....
pkg/analyzer_cli/tool/perf.dart:39: print('usage: perf.dart <bench-id>
<entry.dart>');
On 2016/10/10 19:20:40, Paul Berry wrote:
> Consider using the args package so that we can have a more stable command-line
> API to this tool.

Let's see how this evolves, my hope is that we can keep this as 2 inputs
"bench-id" + entry point, but if we need to start adding more options, we can do
that.

https://codereview.chromium.org/2405943002/diff/1/pkg/analyzer_cli/tool/perf....
pkg/analyzer_cli/tool/perf.dart:52: for (int i = 0; i < 10; i++)
scanFiles(files);
On 2016/10/10 19:20:40, Paul Berry wrote:
> It looks like the way you're doing the warmup is to run the operation 10x and
> take the sum of all of runs.  What I'd recommend doing instead is:  Run the
> operation 10x, then start a timer, then run 10x more, then stop the timer. 
This
> allows the warmup time to be completely excluded from the benchmark, rather
than
> merely diluted.

Sorry - it is not obvious to see how I'm using this without the benchmark
harness around this. This script currently prints the time it takes on each
iteration individually, so what I'm doing is running it 10 times, then storing
the time of the 10th iteration alone.

https://codereview.chromium.org/2405943002/diff/1/pkg/analyzer_cli/tool/perf....
pkg/analyzer_cli/tool/perf.dart:56: for (int i = 0; i < 10; i++)
parseFiles(files);
On 2016/10/10 19:20:40, Paul Berry wrote:
> Similar comment here.

Similar here :)

[Paul Berry, 2016-10-10 20:39:38]

lgtm

https://codereview.chromium.org/2405943002/diff/1/pkg/analyzer_cli/tool/perf....
File pkg/analyzer_cli/tool/perf.dart (right):

https://codereview.chromium.org/2405943002/diff/1/pkg/analyzer_cli/tool/perf....
pkg/analyzer_cli/tool/perf.dart:52: for (int i = 0; i < 10; i++)
scanFiles(files);
On 2016/10/10 19:30:01, Siggi Cherem (dart-lang) wrote:
> On 2016/10/10 19:20:40, Paul Berry wrote:
> > It looks like the way you're doing the warmup is to run the operation 10x
and
> > take the sum of all of runs.  What I'd recommend doing instead is:  Run the
> > operation 10x, then start a timer, then run 10x more, then stop the timer. 
> This
> > allows the warmup time to be completely excluded from the benchmark, rather
> than
> > merely diluted.
> 
> Sorry - it is not obvious to see how I'm using this without the benchmark
> harness around this. This script currently prints the time it takes on each
> iteration individually, so what I'm doing is running it 10 times, then storing
> the time of the 10th iteration alone.

Ah, ok.  I didn't realize that.  In which case what you're doing seems fine to
me.

[Siggi Cherem (dart-lang), 2016-10-10 21:54:26]

Description was changed from

==========
Minor updates to frontend perf tool: warm up & derive .packages directly.

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

to

==========
Minor updates to frontend perf tool: warm up & derive .packages directly.

BUG=
R=paulberry@google.com

Committed:
https://github.com/dart-lang/sdk/commit/e79c120827538abbc5778a442b58cb47c968ec6a
==========

[Siggi Cherem (dart-lang), 2016-10-10 21:54:28]

Committed patchset #1 (id:1) manually as
e79c120827538abbc5778a442b58cb47c968ec6a (presubmit successful).