To: linux-kernel@vger.kernel.org
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Subject: Re: [RFC][PATCH] Add prctl to set sibling thread names
From: Sean Foley <Sean_Foley@ca.ibm.com>
Message-ID: <OFFECD923E.35E1D650-ON85257665.00684B7F-85257665.0068AC54@ca.ibm.com>
Date: Thu, 5 Nov 2009 14:03:33 -0500
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Sean Foley
J9 Real-Time Java Ottawa Technical Lead
Sean_Foley@ca.ibm.com (613)356-5012

KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> wrote on 11/05/2009 
12:42:23 AM:

> > KOSAKI Motohiro wrote:
> > >> KOSAKI Motohiro wrote:
> > >>
> > >>> John, I'd prefer to suggested another design.
> > >>> How about this?
> > >>>
> > >>> 1. remove pid argument from prctl
> > >>> 2. cancel pthread_setname_np()
> > >>> 3. instead, create pthread_attr_setname_np()
> > >>> 4. pthread_create() change own thread name by pthread_attr.
> > >>>
> > >>> It avoid many racy problem automatically.
> > >> Perhaps, but it also greatly reduces the flexibility of the 
> > >> implementation by restricting name changes to create time.
> > > 
> > > Hm.
> > > if your program really need to change another thread name, can 
> you please tell us
> > > why it is necessary and when it is used?
> > 
> > I think John's previous mails covered that pretty well. As for doing 
the 
> > name change at create time, or sometime later, it just seems to me 
that 
> > the flexibility of doing so later is worth having. While I know we 
don't 
> > have to follow other systems implementations, in this case 
> > pthread_setname_np() seems a reasonable model to follow to me.
> 
> You only said your mode is more flexible. but I want to know _why_ 
> this flexibiliby is
> necessay. please tell us concrete use-case.
> 

Kosaki,
Here are a couple of use cases previously posted to this thread on the 
linux kernel mailing list:

dispatch thread adds context to thread names:
http://marc.info/?l=linux-kernel&m=125660141231348&w=2

java language support:
http://marc.info/?l=linux-kernel&m=125666430720863&w=2


Here are some various specific use cases from the web:

Attaching additional info to thread names when used for different 
purposes:
http://osdir.com/ml/java.jsr.166-concurrency/2006-12/msg00105.html

Threads obtained from thread pools being reassigned new names:
http://haacked.com/archive/2004/06/07/546.aspx
http://bytes.com/topic/c-sharp/answers/637152-naming-backgroundworker-thread

Renaming threads scattered across third-party libraries by enumerating 
them and renaming them dynamically:
http://stackoverflow.com/questions/467224/renaming-threads-in-java


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