From d53d04473e0d6ca1765f1117072eec59187a7f7b Mon Sep 17 00:00:00 2001 From: Andreas Hansson Date: Tue, 28 Aug 2012 14:30:31 -0400 Subject: Clock: Rework clocks to avoid tick-to-cycle transformations This patch introduces the notion of a clock update function that aims to avoid costly divisions when turning the current tick into a cycle. Each clocked object advances a private (hidden) cycle member and a tick member and uses these to implement functions for getting the tick of the next cycle, or the tick of a cycle some time in the future. In the different modules using the clocks, changes are made to avoid counting in ticks only to later translate to cycles. There are a few oddities in how the O3 and inorder CPU count idle cycles, as seen by a few locations where a cycle is subtracted in the calculation. This is done such that the regression does not change any stats, but should be revisited in a future patch. Another, much needed, change that is not done as part of this patch is to introduce a new typedef uint64_t Cycle to be able to at least hint at the unit of the variables counting Ticks vs Cycles. This will be done as a follow-up patch. As an additional follow up, the thread context still uses ticks for the book keeping of last activate and last suspend and this should probably also be changed into cycles as well. --- src/arch/x86/mmapped_ipr.hh | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'src/arch/x86/mmapped_ipr.hh') diff --git a/src/arch/x86/mmapped_ipr.hh b/src/arch/x86/mmapped_ipr.hh index 4c3292388..f17b64cad 100644 --- a/src/arch/x86/mmapped_ipr.hh +++ b/src/arch/x86/mmapped_ipr.hh @@ -62,7 +62,7 @@ namespace X86ISA // Make sure we don't trot off the end of data. assert(offset + pkt->getSize() <= sizeof(MiscReg)); pkt->setData(((uint8_t *)&data) + offset); - return xc->getCpuPtr()->ticks(1); + return 1; } inline Tick @@ -76,7 +76,7 @@ namespace X86ISA assert(offset + pkt->getSize() <= sizeof(MiscReg)); pkt->writeData(((uint8_t *)&data) + offset); xc->setMiscReg(index, gtoh(data)); - return xc->getCpuPtr()->ticks(1); + return 1; } } -- cgit v1.2.3