Reduce the amount of log generated with dtrace.

Reduce the amount of log generated with dtrace.

Remove extraneous ppid and errno logging.
Have better variable cleanup characteristics to reduce the amount of kernel
memory leaked while tracing.

Add more comments explaining how the process tracking is done

NOTRY=true
R=cmp@chromium.org
BUG=98636
TEST=


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=140425

[cmp, 2012-06-04 22:21:32]

lgtm, parts were opaque to me but mostly made sense

[M-A Ruel, 2012-06-04 23:28:28]

On 2012/06/04 22:21:32, cmp wrote:
> lgtm, parts were opaque to me but mostly made sense

For the record, with Dtrace, the D script is keeping a map in _kernel mode_
keyed with the process id and with the value 0, 1 or 2. The map is used to know
if the function call should be logged or not. The meaning of each value is
described in the comment. It just occurred to me that dtrace allows constants so
I could use a constant instead, which would be more readable. I'll look at
replacing the 0/1/2 values with named constants instead.

[commit-bot: I haz the power, 2012-06-04 23:28:52]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/maruel@chromium.org/10440073/1

[commit-bot: I haz the power, 2012-06-04 23:31:03]

Change committed as 140425

[MAD, 2012-06-28 13:04:57]

Just found a few old drafts, in case you care... :-)

http://codereview.chromium.org/10440073/diff/1/tools/isolate/trace_inputs.py
File tools/isolate/trace_inputs.py (right):

http://codereview.chromium.org/10440073/diff/1/tools/isolate/trace_inputs.py#...
tools/isolate/trace_inputs.py:984: errno is not printed in the log since this
implementation currently care only
care only -> only cares

http://codereview.chromium.org/10440073/diff/1/tools/isolate/trace_inputs.py#...
tools/isolate/trace_inputs.py:1098: arg1, sizeof(user_addr_t) * (self->argc +
1));
I guess you can't use a loop for this... A bit sad... :-(

http://codereview.chromium.org/10440073/diff/1/tools/isolate/trace_inputs.py#...
tools/isolate/trace_inputs.py:1184: /* These are a good learning experience,
since it traces a lot of things
These are -> This is