Date: Wed, 7 Jan 2004 20:28:16 -0800 From: David Schultz <das@FreeBSD.ORG> To: Poul-Henning Kamp <phk@phk.freebsd.dk> Cc: Peter Jeremy <peterjeremy@optushome.com.au> Subject: Re: perl malloc slow? Message-ID: <20040108042816.GA1813@VARK.homeunix.com> In-Reply-To: <31178.1073481069@critter.freebsd.dk> References: <20040107133930.47eb851b@Magellan.Leidinger.net> <31178.1073481069@critter.freebsd.dk>
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On Wed, Jan 07, 2004, Poul-Henning Kamp wrote: > One of the assumptions I made ten years ago, was that we would expose > more of the possible VM gymnastics to userland and in particular it > was my expectation that it would be cheap for a process to do some > sort of page-flipping or page-exchange. > > This has not materialized in the meantime, and VMwizards have > generally been a lot less than enthusiastic about it when I have > tried to coax them into providing this sort of thing. > > The result is that applications which use realloc() a lot suffer. FWIW, you can do the required gymnastics with mmap() as long as the mapped region is backed by a file. There were some discussions about a year ago about how to extend that idea to swap-backed storage. As I recall, both dillon and wollman wanted it to happen but disagreed about the API, so one nasty bikeshed later, it all evaporated.
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