ITP: octave-2.1.71

Christopher Faylor
Fri Jul 1 14:55:00 GMT 2005

On Fri, Jul 01, 2005 at 06:39:42AM -0700, James R. Phillips wrote:
>--- "John W. Eaton" <> wrote:
>> From: "John W. Eaton" <>
>> Date: Fri, 1 Jul 2005 09:15:43 -0400
>> To:
>> CC:,
>> Subject: Re: ITP: octave-2.1.71
>> On 30-Jun-2005, James R. Phillips wrote:
>>| --- Brian Dessent  wrote:
>>| > Out of curiosity, what if anything have you done to address the SJLJ
>>| > issue/PR 14563?  To summarize, the Cygwin packaged gcc has had
>>| > --enable-sjlj-exceptions for quite a while because DW2 exceptions are
>>| > broken in certain circumstances (namely, when throwing an exception in a
>>| > function used in a callback where the caller doesn't know DW2, eg. win32
>>| > api.)  I don't know much at all about octave but if it does not use any
>>| > callbacks in these situations then it might be worthwhile if you
>>| > compiled the binaries with a DW2 EH-enabled gcc, to avoid the massive
>>| > speed hit reported.
>>| Brian,
>>| This issue occurs in John Eaton's list of stuff to do, but I don't know
>>| anything else about it.
>>I don't think it is my responsibility to fix a problem that is really
>>in GCC or Cygwin.
>>Also, I don't think we can build Octave with some special version of
>>GCC because Octave has a plugin feature, and I think that pretty much
>>requires using the same C++ compiler to build all the parts of Octave
>>and the plugins.
>>BTW, wasn't there a thread about this recently on the
>> list (subject Serious performance problems) that
>>showed that the problem involved thread handling in Cygwin about as
>>much as sjlj exception handling?  I think some progress has been made
>>in addressing the problem.

I'm not sure what this is in reference to but the "serious performance
problem" in that thread came from writing millions of small strings,
which amplified the overhead in thread locking.  There are some things
that can't be fixed owing to the nature of cygwin.  This may be one of

>>Anyway, I think the place to fix this problem is in Cygwin or GCC, not
>>Having Octave compile and run cleanly with mingw is a separate issue,
>>and doesn't really solve the problem for Cgywin users.

Actually, it isn't a separate issue at all.  DW2 exception handling is
an issue common to both mingw and cygwin.  It seems likely that any
solution which addressed the problem on mingw would also work for cygwin.


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