G'Day Chad,
On Tue, Apr 01, 2008 at 07:37:03AM -0400, Chad Mynhier wrote:
> This came up as an RFE during the conference (I believe it's been logged
> as "4012008: brendan() action needed for DTrace Toolkit".)
>
> As everyone here is aware, DTrace is not quite as user friendly as it
> could be. For the uninitiated, it can be confusing to run a DTrace
> script and not see the expected output. Brendan Gregg has addressed
> this in the DTrace Toolkit[1] by including a BEGIN probe in each script
> to alert the uninitiated, i.e.:
>
> dtrace:::BEGIN
> {
> printf("Tracing... Hit Ctrl-C to end.\n");
> }
>
> Unfortunately, this can lead to much unnecessary typing, and it leaves
> open the possibility of human error (e.g., "Tracing... Hit Ctrl-D to
> end.\n") To address these problems, I've implemented the brendan()
> action. The brendan() action addresses both problems in that it is
> shorter to type and that it removes the possibility of errors. (A typo
> in the name of the brendan() action, e.g., brandon(), would be caught as
> an error by the D compiler.)
The extra text also inflates the DTraceToolkit by a few megabytes; there
are also portability issues for systems that don't support printf(), or the
ability to print both capital and lower case letters at the same time.
A ported brendan() action could print all caps if need be, especially
useful for the thriving C-64 DTrace port.
> The DTrace test suite script for this, misc/tst.brendan.d, demonstrates
> the usage:
>
> ------------------------------------------------------------------------
> #pragma D option quiet
>
> BEGIN
> {
> brendan();
> exit(0);
> }
> ------------------------------------------------------------------------
>
> with the resulting output:
>
> ------------------------------------------------------------------------
> Tracing... Hit Ctrl-C to end.
>
> ------------------------------------------------------------------------
>
>
> I've put up a webrev for this at the following URL:
>
> http://cr.opensolaris.org/~cmynhier/brendan/
This is great work! :)
This webrev can seriously be used as a reference for understanding DTrace
action internals - including the test suite addition.
Brendan
--
Brendan
[CA, USA]
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