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SubjectRe: First kernel patch (optimization)
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On 2015-09-18 05:31, Raymond Jennings wrote:
> On 09/18/15 00:42, Greg KH wrote:
>> On Thu, Sep 17, 2015 at 11:12:51PM -0400, Theodore Ts'o wrote:
>>> On Wed, Sep 16, 2015 at 01:26:51PM -0400, Josh Boyer wrote:
>>>> That isn't true. It helps the submitter understand the workflow and
>>>> expectations. What you meant to say is that it doesn't help you.
>>> The problem is that workflow isn't the hard part. It's the part that
>>> can be taught most easily, sure. But people seem to get really hung
>>> up on it, and I fear that we have people who never progress beyond
>>> sending trivial patches and spelling fixes and white space fixes and
>>> micro-optimizations.
>>>
>>> If the "you too can be a kernel developer" classes and web sites and
>>> tutorials also taught people how to take performance measurements, and
>>> something about the scientific measurement, that would be something.
>>> Or if it taught people how to create tests and to run regression
>>> testing. Or if it taught people how to try to do fuzz testing, and
>>> then once they find a sequence which causes crash, how to narrow down
>>> the failure to a specific part of the kernel, and how to fix and
>>> confirm that the kernel no longer crashes with the fix --- that would
>>> be useful.
>>>
>>> If they can understand kernel code; if they can understand the
>>> scientific measurement; if they can understand how to do performance
>>> measurements --- being able to properly format patches is something
>>> which most kernel developers can very easily guide a new contributor
>>> to do correctly. Or in the worst case, it doesn't take much time for
>>> me to fix a whitespace problem and just tell the contributor --- by
>>> the way, I fixed up this minor issue; could you please make sure you
>>> do this in the future?
>>>
>>> But if a test hasn't been tested, or if the contributor things it's a
>>> micro-optimization, but it actually takes more CPU time and/or more
>>> stack space and/or bloats the kernel --- that's much more work for the
>>> kernel maintainer to have to deal with when reviewing a patch.
>>>
>>> So I have a very strong disagreement with the belief that teaching
>>> people the workflow is the more important thing. In my mind, that's
>>> like first focusing on the proper how to properly fill out a golf
>>> score card, and the ettiquette and traditions around handicaps, etc
>>> --- before making sure the prospective player is good at putting and
>>> driving. Personally, I'm terrible at putting and driving, so spending
>>> a lot of time learning how to fill out a golf score card would be a
>>> waste of my time.
>>>
>>> A good kernel programmer has to understand systems thinking; how to
>>> figure out abstractions and when it's a good thing to add a new layer
>>> of abstraction and when it's better to rework an exsting abstraction
>>> layer.
>>>
>>> If we have someone who knows the workflow, but which doesn't
>>> understand systems thinking, or how to do testing, then what? Great,
>>> we've just created another Nick Krause. Do you think encouraging a
>>> Nick Krause helps anyone?
>>>
>>> If people really are hung up on learning the workflow, I don't mind if
>>> they want to learn that part and send some silly micro-optimization or
>>> spelling fix or whitespace fix. But it's really, really important
>>> that they move beyond that. And if they aren't capable of moving
>>> beyond that, trying to inflate are recruitment numbers by encouraging
>>> someone who can only do trivial fixes means that we may be get what we
>>> can easily measure --- but it may not be what we really need as a
>>> community.
>> Ted, you are full of crap.
>>
>> Where do you think that "new developers" come from? Do they show up in
>> our inbox, with full knowledge of kernel internals and OS theory yet
>> they somehow just can't grasp how to submit a patch correctly? Yes,
>> they sometimes rarely do. But for the majority of people who got into
>> Linux, that is not the case at all.
>>
>> People need to start with something simple, and easy, to get over the
>> hurdles of:
>> - generating a patch
>> - sending an email
>> - fixing the email client as it just corrupted the patch
>> - fix the subject line as it was incorrect
>> - fix the changelog as it was missing
>> - fix the email client again as it corrupted the patch in a
>> different way
>> - giving up on using a web email client as it just will not work
>> - figuring out who to send the patch to
>> - fixing the email client as the mailing list bounced the email
>>
>> Those are non-trivial tasks. And by starting with "remove this space"
>> you take the worry away from the specific content of the patch, and let
>> them worry about the "hard" part first.
> +1 for this.
>
> For example, I for one cannot tell you how many times gmail snuck html
> sections into my outgoing emails before I finally caught it red handed
> and switched to using a local native client.
>
It's also worth pointing out that if we don't have people submitting
code cleanups and typo fixes and stuff like that, then either we end up
over time with unmaintainable gibberish, or the people who do know
systems programming spending most of their time trying to deal with
cleaning up the code (and this is coming from someone who works for a
company who's software department used to be almost 50 people and is now
5, and we have exactly this problem (that and for some reason no-one
wants to do any kind of code-review, but that's a separate issue)). So
in a way, they are contributing something useful, just not something
that directly impacts users in any immediate time-frame.

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