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Subject: Re: printing pv slow down question

Author: Uri Blass

Date: 12:24:36 08/15/04

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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



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