Date: Mon, 29 Jan 2001 15:50:33 +1100 From: Peter Jeremy <peter.jeremy@alcatel.com.au> To: Root Dude <julian@elischer.org> Cc: current@FreeBSD.ORG Subject: Re: kernel threading: the first steps [patch] Message-ID: <20010129155033.K52423@gsmx07.alcatel.com.au> In-Reply-To: <200101270833.AAA75738@InterJet.elischer.org>; from julian@elischer.org on Sat, Jan 27, 2001 at 12:33:23AM -0800 References: <200101270833.AAA75738@InterJet.elischer.org>
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On 2001-Jan-27 00:33:23 -0800, Root Dude <julian@elischer.org> wrote: >I've broken the proc structure into 4 structures. Leaving aside the issue of whether or your efforts were a waste of time, I have some comments on the ordering of fields. Since the fields are being re-arranged anyway, I'd like to suggest that the implementation characteristics be taken into account. I'm mainly thinking of padding between fields here. A second, far less important issue is the interaction between field order and code size on the IA32. Given that most structure references are base+offset, there's an extra 3-byte overhead in accessing fields more than 127 bytes from the pointer - there's no direct speed penalty except on the 80386, but there is an indirect penalty for larger code (ie bigger cache footprint). This suggests that fields with a high static reference count should be towards the front of structures. Peter To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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