From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <40A435AA.3030908@chunder.com> Date: Fri, 14 May 2004 12:57:46 +1000 From: Bruce Ellis User-Agent: Mozilla Thunderbird 0.6 (Windows/20040502) MIME-Version: 1.0 To: Fans of the OS Plan 9 from Bell Labs <9fans@cse.psu.edu> Subject: Re: [9fans] brucee's 8c on sources? References: <6765c44618dae2df9f6cbf49db67fc89@plan9.ucalgary.ca> In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Topicbox-Message-UUID: 7a804b8e-eacd-11e9-9e20-41e7f4b1d025 see http://www.chunder.com/plan9/ for some details. basically any expression that involves vlongs, when compiled using the default library vlong stuff, does it's fair share of moving data on and off the stack and calling generic functions. a complex vlong expr can produce pages of code. the new 8c generates native instructions and uses registers for most ops. another good speedup is a simple vlong assignment, which used to be MOVL; CLD; REP; MOVSL; and is now MOVL; MOVL - the former suffers from many cycles of setup. it is probably worth extending this to copies of larger structures but the tradeoff depends on the flavour of x86. why fossil? well it is very vlongy. brucee Russ Cox wrote: >>given the speed improvements fossil exhibits when compiled with the >>new 8c i'd very much like to recompile my kernels with it :). > > Really? How much improved? What's improved? Latency? > It surprises me that 64-bit computation was a bottleneck, > even in fossil.