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[Caml-list] Strange slowness of input_line on mingw
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Date: -- (:)
From: Sven Luther <luther@d...>
Subject: Re: [Caml-list] Strange slowness of input_line on mingw
On Mon, Oct 28, 2002 at 06:14:37PM +0100, M E Leypold @ labnet wrote:
> Yaron M. Minsky writes:
>  > So, any other ideas, or suggestion as to how to narrow down the problem?
> Rather generic: Some kind of system call tracing (is that possible
> with mingw?), to find out, wether the things happening between
> userland and kernel are roughly equivalent in both cases. I mean: Same
> number of reads, reading chunks around the same size and so on. If
> not, then I'd look for a problem/difference in the C-Runtime against
> which the OCaml intepreter (or the executable of your programm) are
> linked.
> If things really happen in a different way deeper in userland, the GC
> statistics might be different. Try printing that (I personally do not
> believe it, but strange things happen now and then). 
> Another Idea: Is your file large? If yes, the OCaml program might use
> more memory (nothing is freed until th GC hit's the first time). And
> another rather wild hypothesis is, that the kernel might be somehow
> unwilling to grant that amount of memory and takes its time. But that
> would mean that the OCaml program's process is blocked during a kernel
> call for some time. Can you take pure user cpu time in windows? If
> yes: try that.
> All this is rather generic. I'm no expert on how the OCaml system
> works internally or interfaces with the host system. Taking this
> profiles would be just an attempt to find more differences between
> 'wc' and the OCaml implementation to have some data for more educated
> guesses.

BTW, what about re-implementing wc in ocaml using direct reading of the
file without creating strings, and measure the time taken by this ?


Sven Luther
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