Enables the CheckerCPU to be selected at runtime with the --checker option
from the configs/example/fs.py and configs/example/se.py configuration
files. Also merges with the SE/FS changes.
This patch is adding a clearer design intent to all objects that would
not be complete without a port proxy by making the proxies members
rathen than dynamically allocated. In essence, if NULL would not be a
valid value for the proxy, then we avoid using a pointer to make this
clear.
The same approach is used for the methods using these proxies, such as
loadSections, that now use references rather than pointers to better
reflect the fact that NULL would not be an acceptable value (in fact
the code would break and that is how this patch started out).
Overall the concept of "using a reference to express unconditional
composition where a NULL pointer is never valid" could be done on a
much broader scale throughout the code base, but for now it is only
done in the locations affected by the proxies.
Brings the CheckerCPU back to life to allow FS and SE checking of the
O3CPU. These changes have only been tested with the ARM ISA. Other
ISAs potentially require modification.
This patch cleans up forward declarations and a member-function
prototype that still referred to the old FunctionalPort, VirtualPort
and TranslatingPort. There is no change in functionality.
Port proxies are used to replace non-structural ports, and thus enable
all ports in the system to correspond to a structural entity. This has
the advantage of accessing memory through the normal memory subsystem
and thus allowing any constellation of distributed memories, address
maps, etc. Most accesses are done through the "system port" that is
used for loading binaries, debugging etc. For the entities that belong
to the CPU, e.g. threads and thread contexts, they wrap the CPU data
port in a port proxy.
The following replacements are made:
FunctionalPort > PortProxy
TranslatingPort > SETranslatingPortProxy
VirtualPort > FSTranslatingPortProxy
--HG--
rename : src/mem/vport.cc => src/mem/fs_translating_port_proxy.cc
rename : src/mem/vport.hh => src/mem/fs_translating_port_proxy.hh
rename : src/mem/translating_port.cc => src/mem/se_translating_port_proxy.cc
rename : src/mem/translating_port.hh => src/mem/se_translating_port_proxy.hh
This change pulls the instruction decoding machinery (including caches) out of
the StaticInst class and puts it into its own class. This has a few intrinsic
benefits. First, the StaticInst code, which has gotten to be quite large, gets
simpler. Second, the code that handles decode caching is now separated out
into its own component and can be looked at in isolation, making it easier to
understand. I took the opportunity to restructure the code a bit which will
hopefully also help.
Beyond that, this change also lays some ground work for each ISA to have its
own, potentially stateful decode object. We'd be able to include less
contextualizing information in the ExtMachInst objects since that context
would be applied at the decoder. Also, the decoder could "know" ahead of time
that all the instructions it's going to see are going to be, for instance, 64
bit mode, and it will have one less thing to check when it decodes them.
Because the decode caching mechanism has been separated out, it's now possible
to have multiple caches which correspond to different types of decoding
context. Having one cache for each element of the cross product of different
configurations may become prohibitive, so it may be desirable to clear out the
cache when relatively static state changes and not to have one for each
setting.
Because the decode function is no longer universally accessible as a static
member of the StaticInst class, a new function was added to the ThreadContexts
that returns the applicable decode object.
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.
This code is no longer needed because of the preceeding change which adds a
StaticInstPtr parameter to the fault's invoke method, obviating the only use
for this pair of functions.
Changes so that InOrder can work for a non-delay-slot ISA like Alpha. Typically, changes have to do with handling misspeculated branches at different points in pipeline
Basically merge it in with Halted.
Also had to get rid of a few other functions that
called ThreadContext::deallocate(), including:
- InOrderCPU's setThreadRescheduleCondition.
- ThreadContext::exit(). This function was there to avoid terminating
simulation when one thread out of a multi-thread workload exits, but we
need to find a better (non-cpu-centric) way.
the primary identifier for a hardware context should be contextId(). The
concept of threads within a CPU remains, in the form of threadId() because
sometimes you need to know which context within a cpu to manipulate.
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.
Right now this introduces a minor memory leak as old physPorts and virtPorts are not deleted when new ones are created. A flyspray task has been created for this issue. It can not be resolved until we determine how the bus will handle giving out ID's to functional ports that may be deleted.
src/cpu/o3/cpu.cc:
src/cpu/simple/atomic.cc:
src/cpu/simple/timing.cc:
Change the setup of the physPort and virtPort to instead happen every time the CPU has a context activated. This is a little high overhead, but keeps it working correctly when the CPU does not have a physical memory attached to it until it switches in (like the case of switch CPUs).
src/cpu/o3/thread_context.hh:
Change function from being called at init() to just being called whenever the memory ports need to be connected.
src/cpu/o3/thread_context_impl.hh:
Update this to not delete the port if it's the same as the virtPort.
src/cpu/thread_context.hh:
Change function from being called at init() to whenever the memory ports need to be connected.
src/cpu/thread_state.cc:
Instead of initializing the ports, simply connect them, deleting any old ports that might exist. This allows these functions to be called multiple times.
src/cpu/thread_state.hh:
Ports are no longer initialized, but rather connected at context activation time.
--HG--
extra : convert_revision : e399ce5dfbd6ad658c953a7c9c7b69b89a70219e
src/cpu/o3/alpha/cpu_impl.hh:
Handle the PhysicalPort and VirtualPort in the ThreadState.
src/cpu/o3/cpu.cc:
Initialize the thread context.
src/cpu/o3/thread_context.hh:
Add new function to initialize thread context.
src/cpu/o3/thread_context_impl.hh:
Use code now put into function.
src/cpu/simple_thread.cc:
Move code to ThreadState and use the new helper function.
src/cpu/simple_thread.hh:
Remove init() in this derived class; use init() from ThreadState base class.
src/cpu/thread_state.cc:
Move setting up of Physical and Virtual ports here. Change getMemFuncPort() to connectToMemFunc(), which connects a port to a functional port of the memory object below the CPU.
src/cpu/thread_state.hh:
Update functions.
--HG--
extra : convert_revision : ff254715ef0b259dc80d08f13543b63e4024ca8d
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--
extra : convert_revision : 9bb199b4085903e49ffd5a4c8ac44d11460d988c
Major thing was to not execute commit if there are no active threads in CPU.
src/cpu/o3/alpha/thread_context.hh:
call deallocate instead of deallocateContext
src/cpu/o3/commit_impl.hh:
dont run commit stage if there are no instructions
src/cpu/o3/cpu.cc:
add deallocate event, deactivateThread function, and edit deallocateContext.
src/cpu/o3/cpu.hh:
add deallocate event and add optional delay to deallocateContext
src/cpu/o3/thread_context.hh:
optional delay for deallocate
src/cpu/o3/thread_context_impl.hh:
edit DPRINTFs to say Thread Context instead of Alpha TC
src/cpu/thread_context.hh:
optional delay
src/sim/syscall_emul.hh:
name stuff
--HG--
extra : convert_revision : f4033e1f66b3043d30ad98dcc70d8b193dea70b6
src/cpu/o3/alpha/thread_context.hh:
Use 'this' when accessing cpu
src/cpu/o3/cpu.hh:
add numActiveThreds function
src/cpu/o3/thread_context.hh:
forward class declarations
src/cpu/o3/thread_context_impl.hh:
add quiesce event header file
src/cpu/thread_context.hh:
add exit() function to thread context (read comments in file)
src/sim/syscall_emul.cc:
adjust exitFunc syscall
--HG--
extra : convert_revision : 323dc871e2b4f4ee5036be388ceb6634cd85a83e
Use O3CPU when building instead of AlphaO3CPU.
I could use some better python magic in the cpu_models.py file!
AUTHORS:
add middle initial
SConstruct:
change from AlphaO3CPU to O3CPU
src/cpu/SConscript:
edits to build O3CPU instead of AlphaO3CPU
src/cpu/cpu_models.py:
change substitution template to use proper CPU EXEC CONTEXT For O3CPU Model...
Actually, some Python expertise could be used here. The 'env' variable is not
passed to this file, so I had to parse through the ARGV to find the ISA...
src/cpu/o3/base_dyn_inst.cc:
src/cpu/o3/bpred_unit.cc:
src/cpu/o3/commit.cc:
src/cpu/o3/cpu.cc:
src/cpu/o3/cpu.hh:
src/cpu/o3/decode.cc:
src/cpu/o3/fetch.cc:
src/cpu/o3/iew.cc:
src/cpu/o3/inst_queue.cc:
src/cpu/o3/lsq.cc:
src/cpu/o3/lsq_unit.cc:
src/cpu/o3/mem_dep_unit.cc:
src/cpu/o3/rename.cc:
src/cpu/o3/rob.cc:
use isa_specific.hh
src/sim/process.cc:
only initi NextNPC if not ALPHA
src/cpu/o3/alpha/cpu.cc:
alphao3cpu impl
src/cpu/o3/alpha/cpu.hh:
move AlphaTC to it's own file
src/cpu/o3/alpha/cpu_impl.hh:
Move AlphaTC to it's own file ...
src/cpu/o3/alpha/dyn_inst.cc:
src/cpu/o3/alpha/dyn_inst.hh:
src/cpu/o3/alpha/dyn_inst_impl.hh:
include paths
src/cpu/o3/alpha/impl.hh:
include paths, set default MaxThreads to 2 instead of 4
src/cpu/o3/alpha/params.hh:
set Alpha Specific Params here
src/python/m5/objects/O3CPU.py:
add O3CPU class
src/cpu/o3/SConscript:
include isa-specific build files
src/cpu/o3/alpha/thread_context.cc:
NEW HOME of AlphaTC
src/cpu/o3/alpha/thread_context.hh:
new home of AlphaTC
src/cpu/o3/isa_specific.hh:
includes ISA specific files
src/cpu/o3/params.hh:
base o3 params
src/cpu/o3/thread_context.hh:
base o3 thread context
src/cpu/o3/thread_context_impl.hh:
base o3 thead context impl
--HG--
rename : src/cpu/o3/alpha_cpu.cc => src/cpu/o3/alpha/cpu.cc
rename : src/cpu/o3/alpha_cpu.hh => src/cpu/o3/alpha/cpu.hh
rename : src/cpu/o3/alpha_cpu_builder.cc => src/cpu/o3/alpha/cpu_builder.cc
rename : src/cpu/o3/alpha_cpu_impl.hh => src/cpu/o3/alpha/cpu_impl.hh
rename : src/cpu/o3/alpha_dyn_inst.cc => src/cpu/o3/alpha/dyn_inst.cc
rename : src/cpu/o3/alpha_dyn_inst.hh => src/cpu/o3/alpha/dyn_inst.hh
rename : src/cpu/o3/alpha_dyn_inst_impl.hh => src/cpu/o3/alpha/dyn_inst_impl.hh
rename : src/cpu/o3/alpha_impl.hh => src/cpu/o3/alpha/impl.hh
rename : src/cpu/o3/alpha_params.hh => src/cpu/o3/alpha/params.hh
rename : src/python/m5/objects/AlphaO3CPU.py => src/python/m5/objects/O3CPU.py
extra : convert_revision : d377d6417452ac337bc502f28b2fde907d6b340e
