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Subject: Re: printing pv slow down question

Author: Mathieu Pagé

Date: 15:46:04 08/15/04

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On August 15, 2004 at 15:24:36, Uri Blass wrote:

>On August 15, 2004 at 15:16:17, Mathieu Pagé wrote:
>
>>On August 15, 2004 at 12:13:59, Uri Blass wrote:
>>
>>>On August 15, 2004 at 12:01:56, Andrew Platt wrote:
>>>
>>>>Do not underestimate the cost of writing to Windows terminals! Particularly if
>>>>the output is unbuffered it can be quite intense. Try this: Open a file as a
>>>>test and send the output to there (default buffering of fopen is fine). See if
>>>>you see the same slowdown.
>>>>
>>>>Andy.
>>>
>>>It cannot be the cost of writing because the difference between times when there
>>>is no additional writing is also significantly bigger.
>>>
>>>I do not understand what is unbuffered output.
>>>
>>>I use fflush(stdout) after every printf but I know that I need to use
>>>fflush(stdout) after lines that I print (otherwise the program may work in text
>>>mode but not under winboard)
>>
>>Hi Uri,
>>
>>You are right, in order to work in Winboard you need to do fflush() after each
>>output if you want winboard to get it instantly. However there is some
>>informations that you send to winboard that did not need to be send so rapidely
>>(like PV informations). So I sugest you to try (i did not) to use fflush only
>>after critical informations like returning move, pong, etc. But not after pv.
>>I'm absolutely not sure if it will help, so you should test it.
>>
>>Mathieu P.
>
>If the problem is speed of fflush I could expect no slow down when there is no
>additional fflush but it is not the case.
>
>I already found a way to do the code more clearer and faster by dividing the
>file iterate.c to 2 files when one of them is for searching the root moves like
>crafty.
>
>Movei still has not enough files relative to crafty and I probably should divide
>the program to more files.
>
>Uri

Are you telling that the overhaed you are experiencing is not due to writing to
stdout, but due to youre pv retreiving function ?

Mathieu Pagé



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