Subj : Re: Lockable objects
To   : comp.programming.threads
From : doug
Date : Thu May 19 2005 10:17 pm


"Uenal Mutlu" <520001085531-0001@t-online.de> wrote in message 
news:d6iuin$l9k$03$1@news.t-online.com...
> "doug" wrote>
>> "Uenal Mutlu" wrote in message
>> > "doug" wrote
>> >>
>> >> "Sergei Organov"  wrote in message
>> >> > "Uenal Mutlu" writes:
>> >> >> A mutex can be realized in just 8 bytes (counter and threadid).
>> >> >> These methods would be like any other method of the object:
>> >> >> just use which you want/need/like, or don't use at all: you have 
>> >> >> the
>> >> >> choice.
>> >> >
>> >> > Didn't you forget to attach a condvar to every non-trivial object as
>> >> > well? Just imagine how useful it is to have it ready for signalling 
>> >> > and
>> >> > for waiting for changes to the object!
>> >> >
>> >> >> The advantage of having such an "architecture" in the language
>> >> >> gives far more possibilities for the users.
>> >> >
>> >> > ... and then we end up with a "class Everything" that provides all 
>> >> > the
>> >> > imaginable possibilities to the user, including automated check 
>> >> > against
>> >> > famous Uenal Mutlu deadlock theorem. We have reached ultimate
>> >> > perfectness! Congratulations! The only problem is that it seems that
>> >> > nobody but Uenal Mutlu will use the language then.
>> >> >
>> >> >> And: multithreading has become a de facto standard in programming,
>> >> >> esp. in application programming.
>> >> >
>> >> > ... mostly due to the fact that one famous OS doesn't provide a
>> >> > sensible
>> >> > way to deal with non-trivial IO without threads and has pure support
>> >> > for
>> >> > processes, IMHO. Hard times during which programmers learn *not to 
>> >> > use
>> >> > threads* where they are inappropriate I foresee :(
>> >> >
>> >> > --
>> >> > Sergei.
>> >>
>> >> I imagine someone's just finished the latest chapter in their 
>> >> threading
>> >> book.  However, it doesn't look like he's actually *ready*, just
>> >> skimming.
>> >>
>> >> So here's some random babbling.  I don't see why i should bother to
>> >> formulate my points properly, if a) you don't respond to them, and b)
>> >> your
>> >> postings aren't just random, their plain nonsense!
>> >> - why 8 bytes?  Is that just because that's what your current OS uses?
>> >> what
>> >> about other systems?  what about things like alignment?  especially on
>> >> SMP
>> >> systems?
>> >> - counter and thread id.  Didn't you forget the actual lock itself?
>> >> - what use is GetLockedCount() or IsLocked()?  (Unless it's for
>> >> debugging/diagnostics).  When called by the non-owner, they're
>> >> unreliable,
>> >> and there's no reason an owner should need to call these.  Providing 
>> >> them
>> >> just promotes extremely poor design.
>> >> - what about timed acquires?
>> >> - you've forgotten about signal semaphores/condition variables.  It's
>> >> likely
>> >> you don't know what these are.
>> >> - what about single-writer, multi-read locks?
>> >> - finally, recursive mutexes.  No, no, no, no, no.  Especially, with
>> >> multi-cores becoming common, if you write multi-threaded programs, a
>> >> recursive lock (as others have pointed out to you), serves one and 
>> >> only
>> >> one
>> >> purpose - the ability to put a bottleneck in your program.  (Maybe 
>> >> two -
>> >> the
>> >> abliity to hide bugs until your customer runs the code.)
>> >
>> > Are these questions directed to me?
>> >
>> Erm...  <tumbleweed....> Yes.
>
> Hmm. you don't seem to be very consistent, do you? Because just yesterday
> you wrote the following:
>
> "doug" wrote
>> That's it, the end.  I'm out.  David bothered to read the code, I was
>> laughing too hard after the second line.
>>
>> I just seriously hope that I never come across you in my professional
>> career, or any of the code you've ever touched.  I will obviously now 
>> avoid
>> Seimens mobile phones.
>
> And you really expect me to answer your questions?
>
>

No, I really don't.  I don't think you can.

(And sorry if I caused offence.  Didn't really think you'd take any notice, 
you don't take any notice of anything else.  Your behaviour here is 
ridiculous.)

.