From bf305c14c47c4bd228c0910ea3bb30ab4bc935e1 Mon Sep 17 00:00:00 2001 From: Nikos Nikoleris Date: Mon, 10 Oct 2016 13:48:08 +0100 Subject: [PATCH] mem: Delay servicing an MSHR after its allocation An MSHR is allocated and the computed latency determines when the MSHR will be ready and can be serviced by the cache. This patch adds a function that allows changing the time that an MSHR is ready and adjusts the queue such that other MSHRs can be serviced first if they are ready. Change-Id: Ie908191fcb3c2d84d4c6f855c8b1e41ca5881bff Reviewed-on: https://gem5-review.googlesource.com/c/12906 Reviewed-by: Daniel Carvalho Maintainer: Nikos Nikoleris --- src/mem/cache/mshr.hh | 10 ++++++++++ src/mem/cache/mshr_queue.cc | 13 ++++++++++++- src/mem/cache/mshr_queue.hh | 11 ++++++++++- 3 files changed, 32 insertions(+), 2 deletions(-) diff --git a/src/mem/cache/mshr.hh b/src/mem/cache/mshr.hh index 56b81b6b2..b94dfb9c5 100644 --- a/src/mem/cache/mshr.hh +++ b/src/mem/cache/mshr.hh @@ -513,6 +513,16 @@ class MSHR : public QueueEntry, public Printable bool trySatisfyFunctional(PacketPtr pkt); + /** + * Adds a delay relative to the current tick to the current MSHR + * @param delay_ticks the desired delay in ticks + */ + void delay(Tick delay_ticks) + { + assert(readyTime <= curTick()); + readyTime = curTick() + delay_ticks; + } + /** * Prints the contents of this MSHR for debugging. */ diff --git a/src/mem/cache/mshr_queue.cc b/src/mem/cache/mshr_queue.cc index e44a21954..f4b80540c 100644 --- a/src/mem/cache/mshr_queue.cc +++ b/src/mem/cache/mshr_queue.cc @@ -1,5 +1,5 @@ /* - * Copyright (c) 2012-2013, 2015-2016 ARM Limited + * Copyright (c) 2012-2013, 2015-2016, 2018 ARM Limited * All rights reserved. * * The license below extends only to copyright in the software and shall @@ -84,6 +84,17 @@ MSHRQueue::moveToFront(MSHR *mshr) } } +void +MSHRQueue::delay(MSHR *mshr, Tick delay_ticks) +{ + mshr->delay(delay_ticks); + auto it = std::find_if(mshr->readyIter, readyList.end(), + [mshr] (const MSHR* _mshr) { + return mshr->readyTime >= _mshr->readyTime; + }); + readyList.splice(it, readyList, mshr->readyIter); +} + void MSHRQueue::markInService(MSHR *mshr, bool pending_modified_resp) { diff --git a/src/mem/cache/mshr_queue.hh b/src/mem/cache/mshr_queue.hh index 1b960a5a2..1e4eaeb51 100644 --- a/src/mem/cache/mshr_queue.hh +++ b/src/mem/cache/mshr_queue.hh @@ -1,5 +1,5 @@ /* - * Copyright (c) 2012-2013, 2015-2016 ARM Limited + * Copyright (c) 2012-2013, 2015-2016, 2018 ARM Limited * All rights reserved. * * The license below extends only to copyright in the software and shall @@ -106,6 +106,15 @@ class MSHRQueue : public Queue */ void moveToFront(MSHR *mshr); + /** + * Adds a delay to the provided MSHR and moves MSHRs that will be + * ready earlier than this entry to the top of the list + * + * @param mshr that needs to be delayed + * @param delay_ticks ticks of the desired delay + */ + void delay(MSHR *mshr, Tick delay_ticks); + /** * Mark the given MSHR as in service. This removes the MSHR from the * readyList or deallocates the MSHR if it does not expect a response. -- 2.30.2