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This step makes it easy to replace the accessor functions
(which still access a global variable) with ones that access
per-thread curTick values.
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These files really aren't general enough to belong in src/base.
This patch doesn't reorder include lines, leaving them unsorted
in many cases, but Nate's magic script will fix that up shortly.
--HG--
rename : src/base/sched_list.hh => src/cpu/sched_list.hh
rename : src/base/timebuf.hh => src/cpu/timebuf.hh
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This change is a low level and pervasive reorganization of how PCs are managed
in M5. Back when Alpha was the only ISA, there were only 2 PCs to worry about,
the PC and the NPC, and the lsb of the PC signaled whether or not you were in
PAL mode. As other ISAs were added, we had to add an NNPC, micro PC and next
micropc, x86 and ARM introduced variable length instruction sets, and ARM
started to keep track of mode bits in the PC. Each CPU model handled PCs in
its own custom way that needed to be updated individually to handle the new
dimensions of variability, or, in the case of ARMs mode-bit-in-the-pc hack,
the complexity could be hidden in the ISA at the ISA implementation's expense.
Areas like the branch predictor hadn't been updated to handle branch delay
slots or micropcs, and it turns out that had introduced a significant (10s of
percent) performance bug in SPARC and to a lesser extend MIPS. Rather than
perpetuate the problem by reworking O3 again to handle the PC features needed
by x86, this change was introduced to rework PC handling in a more modular,
transparent, and hopefully efficient way.
PC type:
Rather than having the superset of all possible elements of PC state declared
in each of the CPU models, each ISA defines its own PCState type which has
exactly the elements it needs. A cross product of canned PCState classes are
defined in the new "generic" ISA directory for ISAs with/without delay slots
and microcode. These are either typedef-ed or subclassed by each ISA. To read
or write this structure through a *Context, you use the new pcState() accessor
which reads or writes depending on whether it has an argument. If you just
want the address of the current or next instruction or the current micro PC,
you can get those through read-only accessors on either the PCState type or
the *Contexts. These are instAddr(), nextInstAddr(), and microPC(). Note the
move away from readPC. That name is ambiguous since it's not clear whether or
not it should be the actual address to fetch from, or if it should have extra
bits in it like the PAL mode bit. Each class is free to define its own
functions to get at whatever values it needs however it needs to to be used in
ISA specific code. Eventually Alpha's PAL mode bit could be moved out of the
PC and into a separate field like ARM.
These types can be reset to a particular pc (where npc = pc +
sizeof(MachInst), nnpc = npc + sizeof(MachInst), upc = 0, nupc = 1 as
appropriate), printed, serialized, and compared. There is a branching()
function which encapsulates code in the CPU models that checked if an
instruction branched or not. Exactly what that means in the context of branch
delay slots which can skip an instruction when not taken is ambiguous, and
ideally this function and its uses can be eliminated. PCStates also generally
know how to advance themselves in various ways depending on if they point at
an instruction, a microop, or the last microop of a macroop. More on that
later.
Ideally, accessing all the PCs at once when setting them will improve
performance of M5 even though more data needs to be moved around. This is
because often all the PCs need to be manipulated together, and by getting them
all at once you avoid multiple function calls. Also, the PCs of a particular
thread will have spatial locality in the cache. Previously they were grouped
by element in arrays which spread out accesses.
Advancing the PC:
The PCs were previously managed entirely by the CPU which had to know about PC
semantics, try to figure out which dimension to increment the PC in, what to
set NPC/NNPC, etc. These decisions are best left to the ISA in conjunction
with the PC type itself. Because most of the information about how to
increment the PC (mainly what type of instruction it refers to) is contained
in the instruction object, a new advancePC virtual function was added to the
StaticInst class. Subclasses provide an implementation that moves around the
right element of the PC with a minimal amount of decision making. In ISAs like
Alpha, the instructions always simply assign NPC to PC without having to worry
about micropcs, nnpcs, etc. The added cost of a virtual function call should
be outweighed by not having to figure out as much about what to do with the
PCs and mucking around with the extra elements.
One drawback of making the StaticInsts advance the PC is that you have to
actually have one to advance the PC. This would, superficially, seem to
require decoding an instruction before fetch could advance. This is, as far as
I can tell, realistic. fetch would advance through memory addresses, not PCs,
perhaps predicting new memory addresses using existing ones. More
sophisticated decisions about control flow would be made later on, after the
instruction was decoded, and handed back to fetch. If branching needs to
happen, some amount of decoding needs to happen to see that it's a branch,
what the target is, etc. This could get a little more complicated if that gets
done by the predecoder, but I'm choosing to ignore that for now.
Variable length instructions:
To handle variable length instructions in x86 and ARM, the predecoder now
takes in the current PC by reference to the getExtMachInst function. It can
modify the PC however it needs to (by setting NPC to be the PC + instruction
length, for instance). This could be improved since the CPU doesn't know if
the PC was modified and always has to write it back.
ISA parser:
To support the new API, all PC related operand types were removed from the
parser and replaced with a PCState type. There are two warts on this
implementation. First, as with all the other operand types, the PCState still
has to have a valid operand type even though it doesn't use it. Second, using
syntax like PCS.npc(target) doesn't work for two reasons, this looks like the
syntax for operand type overriding, and the parser can't figure out if you're
reading or writing. Instructions that use the PCS operand (which I've
consistently called it) need to first read it into a local variable,
manipulate it, and then write it back out.
Return address stack:
The return address stack needed a little extra help because, in the presence
of branch delay slots, it has to merge together elements of the return PC and
the call PC. To handle that, a buildRetPC utility function was added. There
are basically only two versions in all the ISAs, but it didn't seem short
enough to put into the generic ISA directory. Also, the branch predictor code
in O3 and InOrder were adjusted so that they always store the PC of the actual
call instruction in the RAS, not the next PC. If the call instruction is a
microop, the next PC refers to the next microop in the same macroop which is
probably not desirable. The buildRetPC function advances the PC intelligently
to the next macroop (in an ISA specific way) so that that case works.
Change in stats:
There were no change in stats except in MIPS and SPARC in the O3 model. MIPS
runs in about 9% fewer ticks. SPARC runs with 30%-50% fewer ticks, which could
likely be improved further by setting call/return instruction flags and taking
advantage of the RAS.
TODO:
Add != operators to the PCState classes, defined trivially to be !(a==b).
Smooth out places where PCs are split apart, passed around, and put back
together later. I think this might happen in SPARC's fault code. Add ISA
specific constructors that allow setting PC elements without calling a bunch
of accessors. Try to eliminate the need for the branching() function. Factor
out Alpha's PAL mode pc bit into a separate flag field, and eliminate places
where it's blindly masked out or tested in the PC.
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Also move the "Fault" reference counted pointer type into a separate file,
sim/fault.hh. It would be better to name this less similarly to sim/faults.hh
to reduce confusion, but fault.hh matches the name of the type. We could change
Fault to FaultPtr to match other pointer types, and then changing the name of
the file would make more sense.
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When each load or store is sent to the LSQ, we check whether it will cross a
cache line boundary and, if so, split it in two. This creates two TLB
translations and two memory requests. Care has to be taken if the first
packet of a split load is sent but the second blocks the cache. Similarly,
for a store, if the first packet cannot be sent, we must store the second
one somewhere to retry later.
This modifies the LSQSenderState class to record both packets in a split
load or store.
Finally, a new const variable, HasUnalignedMemAcc, is added to each ISA
to indicate whether unaligned memory accesses are allowed. This is used
throughout the changed code so that compiler can optimise away code dealing
with split requests for ISAs that don't need them.
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This object encapsulates (or will eventually) the identity and characteristics
of the ISA in the CPU.
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object.
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Make interrupts use the new wakeup method, and pull all of the interrupt
stuff into the cpu base class so that only the wakeup code needs to be updated.
I tried to make wakeup, wakeCPU, and the various other mechanisms for waking
and sleeping a little more sane, but I couldn't understand why the statistics
were changing the way they were. Maybe we'll try again some day.
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This is to prevent the assertion from firing if you have a large multicore.
Also make sure that it's not compiled in when NDEBUG is defined
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across the subclasses. generally make it so that member data is _cpuId and
accessor functions are cpuId(). The ID val comes from the python (default -1 if
none provided), and if it is -1, the index of cpuList will be given. this has
passed util/regress quick and se.py -n4 and fs.py -n4 as well as standard
switch.
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comments.
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Removing hwrei causes
the instruction after the hwrei to be fetched before the ITB/DTB_CM register is updated in a call pal
call sys and thus the translation fails because the user is attempting to access a super page address.
Minimally, it seems as though some sort of fetch stall or refetch after a hwrei is required. I think
this works currently because the hwrei uses the exec context interface, and the o3 stalls when that occurs.
Additionally, these changes don't update the LOCK register and probably break ll/sc. Both o3 changes were
removed since a great deal of manual patching would be required to only remove the hwrei change.
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For now, there is still a single global event queue, but this is
necessary for making the steps towards a parallelized m5.
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A whole bunch of stuff has been converted to use the new params stuff, but
the CPU wasn't one of them. While we're at it, make some things a bit
more stylish. Most of the work was done by Gabe, I just cleaned stuff up
a bit more at the end.
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--HG--
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--HG--
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--HG--
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--HG--
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--HG--
extra : convert_revision : 3c480537bf38f74f0f1d72e75c70aa46ba91b759
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into ahchoo.blinky.homelinux.org:/home/gblack/m5/newmem-o3-micro
src/cpu/o3/fetch_impl.hh:
hand merge
--HG--
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--HG--
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handling. Branch delay slots need to be squash on a mispredict as well because the nnpc they saw was incorrect.
--HG--
extra : convert_revision : 8b9c603616bcad254417a7a3fa3edfb4c8728719
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squashed anyway on a mispredict. This is because the NNPC value they saw when executing was incorrect.
--HG--
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functions.
src/cpu/o3/alpha/cpu_impl.hh:
Pass ISA-specific O3 CPU to FullO3CPU as a constructor parameter instead of using setCPU functions.
--HG--
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into zamp.eecs.umich.edu:/z/ktlim2/clean/tmp/clean2
src/cpu/base_dyn_inst.hh:
Hand merge. Line is no longer needed because it's handled in the ISA.
--HG--
extra : convert_revision : 0be4067aa38759a5631c6940f0167d48fde2b680
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1. Set CPU ID in all modes for the O3 CPU.
2. Use nextCycle() function to prevent phase drift in O3 CPU.
3. Remove assertion in rename map that is no longer true.
src/cpu/o3/alpha/cpu_builder.cc:
Allow for CPU id in all modes, not just full system. Also include a parameter that was left out by accident.
src/cpu/o3/alpha/cpu_impl.hh:
Set the CPU ID properly.
src/cpu/o3/cpu.cc:
src/cpu/o3/cpu.hh:
Use nextCycle() function so that the CPU does not get out of phase when starting up from quiesces.
src/cpu/o3/rename_map.cc:
Remove assertion that is no longer true.
tests/configs/o3-timing.py:
Set CPU's id to 0.
--HG--
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1. Make sure connectMemPorts() only gets called when the CPU's peer gets changed. This is done by making setPeer() virtual, and overriding it in the CPU's ports. When it gets called on a CPU's port (dcache specifically), it calls the normal setPeer() function, and also connectMemPorts().
2. Consolidate redundant code that handles switching in a CPU.
src/cpu/base.cc:
Move common code of switching over peers to base CPU.
src/cpu/base.hh:
Move common code of switching over peers to BaseCPU.
src/cpu/o3/cpu.cc:
Add in function that updates thread context's ports.
Also use updated function to takeOverFrom() in BaseCPU. This gets rid of some repeated code.
src/cpu/o3/cpu.hh:
Include function to update thread context's memory ports.
src/cpu/o3/lsq.hh:
Add function to dcache port that will update the memory ports upon getting a new peer.
Also include a function that will tell the CPU to update those memory ports.
src/cpu/o3/lsq_impl.hh:
Add function that will update the memory ports upon getting a new peer.
src/cpu/simple/atomic.cc:
src/cpu/simple/timing.cc:
Add function that will update thread context's memory ports upon getting a new peer.
Also use the new BaseCPU's take over from function.
src/cpu/simple/atomic.hh:
Add in function (and dcache port) that will allow the dcache to update memory ports when it gets assigned a new peer.
src/cpu/simple/timing.hh:
Add function that will update thread context's memory ports upon getting a new peer.
src/mem/port.hh:
Make setPeer virtual so that other classes can override it.
--HG--
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architecture defined setSyscallReturn function instead of a duplicate copy.
src/cpu/o3/alpha/cpu.hh:
Got rid of some typedefs, and moved the tlbs to the base o3 cpu.
src/cpu/o3/alpha/thread_context.hh:
src/cpu/o3/cpu.cc:
Moved the tlbs to the base o3 cpu.
--HG--
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for its MemObject instead of having to have a paramter for the MemObject.
configs/example/fs.py:
configs/example/se.py:
src/cpu/simple/base.cc:
src/cpu/simple/base.hh:
src/cpu/simple/timing.cc:
src/cpu/simple_thread.cc:
src/cpu/simple_thread.hh:
src/cpu/thread_state.cc:
src/cpu/thread_state.hh:
tests/configs/o3-timing-mp.py:
tests/configs/o3-timing.py:
tests/configs/simple-atomic-mp.py:
tests/configs/simple-atomic.py:
tests/configs/simple-timing-mp.py:
tests/configs/simple-timing.py:
tests/configs/tsunami-simple-atomic-dual.py:
tests/configs/tsunami-simple-atomic.py:
tests/configs/tsunami-simple-timing-dual.py:
tests/configs/tsunami-simple-timing.py:
No need for mem parameter any more.
src/cpu/checker/cpu.cc:
Use new constructor for simple thread (no more MemObject parameter).
src/cpu/checker/cpu.hh:
Remove MemObject parameter.
src/cpu/memtest/memtest.hh:
Ports now take in their MemObject owner.
src/cpu/o3/alpha/cpu_builder.cc:
Remove mem parameter.
src/cpu/o3/alpha/cpu_impl.hh:
Remove memory parameter and clean up handling of TranslatingPort.
src/cpu/o3/cpu.cc:
src/cpu/o3/cpu.hh:
src/cpu/o3/fetch.hh:
src/cpu/o3/fetch_impl.hh:
src/cpu/o3/mips/cpu_builder.cc:
src/cpu/o3/mips/cpu_impl.hh:
src/cpu/o3/params.hh:
src/cpu/o3/thread_state.hh:
src/cpu/ozone/cpu.hh:
src/cpu/ozone/cpu_builder.cc:
src/cpu/ozone/cpu_impl.hh:
src/cpu/ozone/front_end.hh:
src/cpu/ozone/front_end_impl.hh:
src/cpu/ozone/lw_lsq.hh:
src/cpu/ozone/lw_lsq_impl.hh:
src/cpu/ozone/simple_params.hh:
src/cpu/ozone/thread_state.hh:
src/cpu/simple/atomic.cc:
Remove memory parameter.
--HG--
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has a bug.
src/cpu/o3/commit_impl.hh:
Fixes for compile and sampling.
src/cpu/o3/cpu.cc:
Deallocate and activate threads properly. Also hopefully fix being able to use caches while switching over.
src/cpu/o3/cpu.hh:
Fixes for deallocating and activating threads.
src/cpu/o3/fetch_impl.hh:
src/cpu/o3/lsq_unit.hh:
Handle getting back a BadAddress result from the access.
src/cpu/o3/iew_impl.hh:
More debug output.
src/cpu/o3/lsq_unit_impl.hh:
Fixup store conditional handling (still a bit of a hack, but works now).
Also handle getting back a BadAddress result from the access.
src/cpu/o3/thread_context_impl.hh:
Deallocate context now records if the context should be fully removed.
--HG--
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throughout CPU models
src/arch/alpha/isa_traits.hh:
src/arch/mips/isa_traits.hh:
src/arch/sparc/isa_traits.hh:
define 'ISA_HAS_DELAY_SLOT'
src/cpu/base_dyn_inst.hh:
src/cpu/o3/bpred_unit_impl.hh:
src/cpu/o3/commit_impl.hh:
src/cpu/o3/cpu.cc:
src/cpu/o3/cpu.hh:
src/cpu/o3/decode_impl.hh:
src/cpu/o3/fetch_impl.hh:
src/cpu/o3/iew_impl.hh:
src/cpu/o3/inst_queue_impl.hh:
src/cpu/o3/rename_impl.hh:
src/cpu/simple/base.cc:
use ISA_HAS_DELAY_SLOT instead of THE_ISA == ALPHA_ISA
--HG--
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--HG--
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builds, runs, and gets very very close to completing the hello world
succesfully but there are some minor quirks to iron out. Who would've known a DELAY SLOT introduces that much complexity?! arrgh!
Anyways, a lot of this stuff had to do with my project at MIPS and me needing to know how I was going to get this working for the MIPS
ISA. So I figured I would try to touch it up and throw it in here (I hate to introduce non-completely working components... )
src/arch/alpha/isa/mem.isa:
spacing
src/arch/mips/faults.cc:
src/arch/mips/faults.hh:
Gabe really authored this
src/arch/mips/isa/decoder.isa:
add StoreConditional Flag to instruction
src/arch/mips/isa/formats/basic.isa:
Steven really did this file
src/arch/mips/isa/formats/branch.isa:
fix bug for uncond/cond control
src/arch/mips/isa/formats/mem.isa:
Adjust O3CPU memory access to use new memory model interface.
src/arch/mips/isa/formats/util.isa:
update LoadStoreBase template
src/arch/mips/isa_traits.cc:
update SERIALIZE partially
src/arch/mips/process.cc:
src/arch/mips/process.hh:
no need for this for NOW. ASID/Virtual addressing handles it
src/arch/mips/regfile/misc_regfile.hh:
add in clear() function and comments for future usage of special misc. regs
src/cpu/base_dyn_inst.hh:
add in nextNPC variable and supporting functions.
add isCondDelaySlot function
Update predTaken and mispredicted functions
src/cpu/base_dyn_inst_impl.hh:
init nextNPC
src/cpu/o3/SConscript:
add MIPS files to compile
src/cpu/o3/alpha/thread_context.hh:
no need for my name on this file
src/cpu/o3/bpred_unit_impl.hh:
Update RAS appropriately for MIPS
src/cpu/o3/comm.hh:
add some extra communication variables to aid in handling the
delay slots
src/cpu/o3/commit.hh:
minor name fix for nextNPC functions.
src/cpu/o3/commit_impl.hh:
src/cpu/o3/decode_impl.hh:
src/cpu/o3/fetch_impl.hh:
src/cpu/o3/iew_impl.hh:
src/cpu/o3/inst_queue_impl.hh:
src/cpu/o3/rename_impl.hh:
Fix necessary variables and functions for squashes with delay slots
src/cpu/o3/cpu.cc:
Update function interface ...
adjust removeInstsNotInROB function to recognize delay slots insts
src/cpu/o3/cpu.hh:
update removeInstsNotInROB
src/cpu/o3/decode.hh:
declare necessary variables for handling delay slot
src/cpu/o3/dyn_inst.hh:
Add in MipsDynInst
src/cpu/o3/fetch.hh:
src/cpu/o3/iew.hh:
src/cpu/o3/rename.hh:
declare necessary variables and adjust functions for handling delay slot
src/cpu/o3/inst_queue.hh:
src/cpu/simple/base.cc:
no need for my name here
src/cpu/o3/isa_specific.hh:
add in MIPS files
src/cpu/o3/scoreboard.hh:
dont include alpha specific isa traits!
src/cpu/o3/thread_context.hh:
no need for my name here, i just rearranged where the file goes
src/cpu/static_inst.hh:
add isCondDelaySlot function
src/cpu/o3/mips/cpu.cc:
src/cpu/o3/mips/cpu.hh:
src/cpu/o3/mips/cpu_builder.cc:
src/cpu/o3/mips/cpu_impl.hh:
src/cpu/o3/mips/dyn_inst.cc:
src/cpu/o3/mips/dyn_inst.hh:
src/cpu/o3/mips/dyn_inst_impl.hh:
src/cpu/o3/mips/impl.hh:
src/cpu/o3/mips/params.hh:
src/cpu/o3/mips/thread_context.cc:
src/cpu/o3/mips/thread_context.hh:
MIPS file for O3CPU...mirrors ALPHA definition
--HG--
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--HG--
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into zizzer.eecs.umich.edu:/.automount/zooks/y/ksewell/research/m5-sim/newmem-o3
--HG--
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src/cpu/checker/cpu.hh:
Now that BaseCPU is a MemObject, the checker must define this function.
src/cpu/o3/cpu.cc:
src/cpu/o3/cpu.hh:
src/cpu/o3/fetch.hh:
src/cpu/o3/iew.hh:
src/cpu/o3/lsq.hh:
src/cpu/o3/lsq_unit.hh:
Implement getPort function so the connector can connect the ports properly.
src/cpu/o3/fetch_impl.hh:
src/cpu/o3/lsq_unit_impl.hh:
The connector handles connecting the ports now.
src/python/m5/objects/O3CPU.py:
Add ports to the parameters.
--HG--
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