Date: Mon, 19 Aug 2002 05:46:24 +1000 (EST) From: Bruce Evans <bde@zeta.org.au> To: Julian Elischer <julian@elischer.org> Cc: Ian Dowse <iedowse@maths.tcd.ie>, <arch@FreeBSD.ORG> Subject: Re: Solving the stack gap issue Message-ID: <20020819053656.V16172-100000@gamplex.bde.org> In-Reply-To: <Pine.BSF.4.21.0208181024530.35342-100000@InterJet.elischer.org>
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On Sun, 18 Aug 2002, Julian Elischer wrote: > On Sun, 18 Aug 2002, Ian Dowse wrote: > > > > If there is agreement on the td vs. curthread issue, then that would > > obviously be easy to change. > > A few days ago, Peter gave some comments as to the expense of using > curthread. I must admit this is something where some architectureal > guidance would be a good thing.... maybe something like > "Use a local if you need to access a Per-cpu variable more than twice > in a function", and "passing a thread pointer as an argument (is/is not) > preferable to calling curtread explicitly in the child function". I think passing around pointers equal to curthread won't exactly help efficiency on most machines. I think it is slower at runtime and only faster at compile time on i386's with the current implementation. kern/*c seems to have approximately the same number of references to curthread as callers that take a td arg. Bruce To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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