ByteString I/O Performance

Tomasz Zielonka tomasz.zielonka at
Mon Sep 3 01:11:45 EDT 2007

On Mon, Sep 03, 2007 at 01:40:51AM +0200, Peter Simons wrote:
> One way to get malloc() out of the picture would be to provide a
> variant of hGet that takes an existing, pre-allocated buffer as an
> argument, so that the user can allocate a ByteString once and re-use
> it for every single hGet and hPut.

This seems dangerous. For example, consider that the ByteString can be
referenced by some lazy computation, expecting it to contain the data
from some earlier hGet.

> A different approach would be to try to reduce the cost for malloc()
> by using some sort of pre-allocated pool of ByteStrings behind the
> scenes.

I just wrote this, before I read you proposition:
As safer alternative would be to keep a cache of pre-malloced buffers,
populated by the ByteString finalizer. But the bookkeeping cost could
outweight the benefit of avoiding malloc.

Best regards

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