Re: GDB 7.9.90 available for testing

[David Edelsohn <dje.gcc@gmail.com>]

On Fri, Jul 10, 2015 at 10:33 AM, Pedro Alves <palves@redhat.com> wrote:
> On 07/10/2015 03:04 PM, David Edelsohn wrote:
>> On Thu, Jul 9, 2015 at 11:42 PM, Joel Brobecker <brobecker@adacore.com> wrote:
>>>> I'm not certain if the baselines truly are accurate for all
>>>> buildslaves, but it seems strange to create a release when the
>>>> buildbot testsuite results show patches causing new failures.
>>>
>>> To me, you are saying the same thing, and I don't disagree with you.
>>> I said I didn't know that the buildBots were showing regressions.
>>> Of course I would have held the creation of the branch if I had
>>> known about this. But I didn't, and so here we are. Now we all know,
>>> and the only way forward is to look at those regressions, and decide
>>> what to do. We can and will delay the release if we have to.
>>
>> Joel,
>>
>> We are agreeing.  I was trying to provide some additional information
>> about interpretation of the buildbot status.
>>
>> I am note two things about the buildbots:
>>
>> 1) Their color-coded "regression status" apparently is a comparison of
>> the testsuite between a "base" run and the current run. This is due to
>> few or no targets have completely clean testsuite runs to consider
>> "green".  Because there has been some adjustment and tweaking while
>> buildbots were added, the first run was not necessarily the ideal one
>> to choose as the "base" run, i.e., "regressions" may be due to changes
>> in the measurements after the first "base" run, not new failing tests.
>
> There's no single "base" run, actually.  The baseline is dynamically
> adjusted at each build; it's a moving baseline, and it's per
> test (single PASS/FAIL, not file).  As soon as a test PASSes, it's
> added to the baseline.  That means that if some test is racy, it'll
> sometimes FAIL, and then a few builds later it'll PASS, at which point
> the PASS is recorded in the baseline, and then a few builds again
> later, the test FAIL again, and so the buildbot email report mentions
> the regression against the baseline.  In sum, if a test goes
> FAIL -> PASS -> FAIL -> PASS on and on over builds, you'll constantly
> get reports of regressions against the baseline for that racy test.

Thanks for the clarification.

>
> For each build, you can find the baseline file in the corresponding
> git commit pointed at in the email report.  E.g., see the "baseline"
> file here:
>
>   http://gdb-build.sergiodj.net/cgit/AIX-POWER7-plain/.git/tree/?h=master&id=42b08c842d422ae995d244efeb1a85aa8a082e7b
>
> The gdb.thread/ FAILs you see on AIX seem to fall in that category.
> From the results, it looks to me that those are caused by the AIX port
> not implementing schedlock correctly.  Is anyone from IBM available
> to look at these?
>
> The gdb.cp/var-tag.exp FAILs currently reported on AIX are not really
> regressions, but new FAILs.  And they are really a test problem, not
> a GDB bug.  They actually depend on compiler or debug info format
> used, not system.

My concern is more about GDB on Linux on z Systems and even GDB on
x86-64, not AIX.  AIX is weird.

Shouldn't the buildbots for z Series and x86-64 be green before a release?

Thanks, David