Re: 'Write attribute vs Write procedure.

[Craig Carey <research@ijs.co.nz>]

On Wed, 21 May 2003 02:07:05 +0200, Jano <nono@celes.unizar.es> wrote:

>Hi everybody.
>
>I'm getting abysmal differences in speed when writing large chunks (64k) 
>of data to a stream. The stream is from a socket of Gnat.Sockets, I 
>mention it because I don't know if it has something to do.
>
...

>In the contrary, the 'Write attribute takes like 3-4 seconds of 100% CPU 
>usage, shared more or less equally by my program and the SYSTEM process, 
...
>P.s2: I've tried also with strings, only the 'Write version of course, 
>and results are the same.

I guess that the ACT vendor designed that part of their Ada compiler to
be intolerably inefficient. It would not affect authors of programs
written in a fairly good style.

That speculation could be tested by:
(1) finding out where ACT could have speeded up their X'Write() for TCP
 data, by adding a "pragma Suppress()" pragma statement.
(2) Then that information would be reported in the form of a bug report.
(3) Then the speculation is suggested to be incorrect if a tracking number
  comes back in the tailored response if any.

If the text in the GNAT.Sockets package caused a loss of time in doing
timing tests, then a bug report about the comments in the package could
be sent in to ACT. 

If the topic is about TCP Ada streams then it probably about extremely
simple programs that might be much modified later.


Craig Carey
Bindings to GNAT.Sockets: http://www.ijs.co.nz/code/ada95_http_hdrs.zip