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This patch adds the notion of source- and derived-clock domains to the
ClockedObjects. As such, all clock information is moved to the clock
domain, and the ClockedObjects are grouped into domains.
The clock domains are either source domains, with a specific clock
period, or derived domains that have a parent domain and a divider
(potentially chained). For piece of logic that runs at a derived clock
(a ratio of the clock its parent is running at) the necessary derived
clock domain is created from its corresponding parent clock
domain. For now, the derived clock domain only supports a divider,
thus ensuring a lower speed compared to its parent. Multiplier
functionality implies a PLL logic that has not been modelled yet
(create a separate clock instead).
The clock domains should be used as a mechanism to provide a
controllable clock source that affects clock for every clocked object
lying beneath it. The clock of the domain can (in a future patch) be
controlled by a handler responsible for dynamic frequency scaling of
the respective clock domains.
All the config scripts have been retro-fitted with clock domains. For
the System a default SrcClockDomain is created. For CPUs that run at a
different speed than the system, there is a seperate clock domain
created. This domain incorporates the CPU and the associated
caches. As before, Ruby runs under its own clock domain.
The clock period of all domains are pre-computed, such that no virtual
functions or multiplications are needed when calling
clockPeriod. Instead, the clock period is pre-computed when any
changes occur. For this to be possible, each clock domain tracks its
children.
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This patch adds a 'sys_clock' command-line option and use it to assign
clocks to the system during instantiation.
As part of this change, the default clock in the System class is
removed and whenever a system is instantiated a system clock value
must be set. A default value is provided for the command-line option.
The configs and tests are updated accordingly.
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This patch removes the explicit setting of the clock period for
certain instances of CoherentBus, NonCoherentBus and IOCache where the
specified clock is same as the default value of the system clock. As
all the values used are the defaults, there are no performance
changes. There are similar cases where the toL2Bus is set to use the
parent CPU clock which is already the default behaviour.
The main motivation for these simplifications is to ease the
introduction of clock domains.
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This patch does a bit of tidying up in the bridge code, adding const
where appropriate and also removing redundant checks and adding a few
new ones.
There are no changes to the behaviour of any regressions.
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This patch fixes the CommMonitor local variable names, and also
introduces a variable to capture if it expects to see a response. The
latter check considers both needsResponse and memInhibitAsserted.
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This patch changes the cache timing calculations such that the results
are aligned to clock edges.
Plenty stats change as a results of this patch.
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This patch changes the IEW drain check to include the FU pool as there
can be instructions that are "stored" in FU completion events and thus
not covered by the existing checks. With this patch, we simply include
a check to see if all the FUs are considered non-busy in the next
tick.
Without this patch, the pc-switcheroo-full regression fails after
minor changes to the cache timing (aligning to clock edge).
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This patch fixes an outstanding issue in the cache timing calculations
where an atomic access returned a time in Cycles, but the port
forwarded it on as if it was in Ticks.
A separate patch will update the regression stats.
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This patch fixes a bug in the granularity calculation. For example, if
the high bit is 6 (counting from 0) and we have one interleaving bit,
then the granularity is now 2 ** (6 - 1 + 1) = 64.
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This patch changes the updards snoop packet to avoid allocating and
later deleting it. As the code executes in 0 time and the lifetime of
the packet does not extend beyond the block there is no reason to heap
allocate it.
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This patch removes an unused member to avoid getting compiler warnings
when using clang.
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This patch removes the printing of the SparseHist total in the
stats.txt output file. This has been removed as a sparse histogram has
no total, and therefore this was printing out the value of a
non-local, unrelated variable.
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This patch adds separate actions for requests that missed in the local cache
and messages were sent out to get the requested line. These separate actions
are required for differentiating between the hit and miss latencies in the
statistics collected.
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This patch adds separate actions for requests that missed in the local cache
and messages were sent out to get the requested line. These separate actions
are required for differentiating between the hit and miss latencies in the
statistics collected.
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The patch started of with removing the global variables from the profiler for
profiling the miss latency of requests made to the cache. The corrresponding
histograms have been moved to the Sequencer. These are combined together when
the histograms are printed. Separate histograms are now maintained for
tracking latency of all requests together, of hits only and of misses only.
A particular set of histograms used to use the type GenericMachineType defined
in one of the protocol files. This patch removes this type. Now, everything
that relied on this type would use MachineType instead. To do this, SLICC has
been changed so that multiple machine types can be declared by a controller
in its preamble.
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This patch removes the following three files: RubySlicc_Profiler.sm,
RubySlicc_Profiler_interface.cc and RubySlicc_Profiler_interface.hh.
Only one function prototyped in the file RubySlicc_Profiler.sm. Rest of the
code appearing in any of these files is not in use. Therefore, these files
are being removed.
That one single function, profileMsgDelay(), is being moved to the protocol
files where it is in use. If we need any of these deleted functions, I think
the right way to make them visible is to have the AbstractController class in
a .sm and let the controller state machine inherit from this class. The
AbstractController class can then have the prototypes of these profiling
functions in its definition.
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The m_size variable attempted to track m_prio_heap.size(), but it did so
incorrectly due to the functions reanalyzeMessages and reanalyzeAllMessages().
Since this variable is intended to track m_prio_heap.size(), we can simply
replace instances where m_size is referenced with m_prio_heap.size(), which
has the added bonus of removing the need for m_size.
Note: This patch also removes an extraneous DPRINTF format string designator
from reanalyzeAllMessages()
Committed by: Nilay Vaish <nilay@cs.wisc.edu>
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Transitions from present on PF_Ifetch were missing, causing a crash when
prefetching is enabled.
Committed by: Nilay Vaish <nilay@cs.wisc.edu>
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Previously, .sm files were allowed to use the same name for a type and a
variable. This is unnecessarily confusing and has some bad side effects, like
not being able to declare later variables in the same scope with the same type.
This causes the compiler to complain and die on things like Address Address.
Committed by: Nilay Vaish <nilay@cs.wisc.edu>
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Change all occurrances of Address as a variable name to instead use Addr.
Address is an allowed name in slicc even when Address is also being used as a
type, leading to declarations of "Address Address". While this works, it
prevents adding another field of type Address because the compiler then thinks
Address is a variable name, not type.
Committed by: Nilay Vaish <nilay@cs.wisc.edu>
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The current implementation of the x87 never updates the x87 tag
word. This is currently not a big issue since the simulated x87 never
checks for stack overflows, however this becomes an issue when
switching between a virtualized CPU and a simulated CPU. This
changeset adds support, which is enabled by default, for updating the
tag register to every floating point microop that updates the stack
top using the spm mechanism.
The new tag words is generated by the helper function
X86ISA::genX87Tags(). This function is currently limited to flagging a
stack position as valid or invalid and does not try to distinguish
between the valid, zero, and special states.
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This changeset actually fixes two issues:
* The lfpimm instruction didn't work correctly when applied to a
floating point constant (it did work for integers containing the
bit string representation of a constant) since it used
reinterpret_cast to convert a double to a uint64_t. This caused a
compilation error, at least, in gcc 4.6.3.
* The instructions loading floating point constants in the x87
processor didn't work correctly since they just stored a truncated
integer instead of a double in the floating point register. This
changeset fixes the old microcode by using lfpimm instruction
instead of the limm instructions.
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This patch allows the default x86 state to be used when by CPUs that
use hardware virtualization.
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The current implementation of fprem simply does an fmod and doesn't
simulate any of the iterative behavior in a real fprem. This isn't
normally a problem, however, it can lead to problems when switching
between CPU models. If switching from a real CPU in the middle of an
fprem loop to a simulated CPU, the output of the fprem loop becomes
correupted. This changeset changes the fprem implementation to work
like the one on real hardware.
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Reuse the address finalization code in the TLB instead of replicating
it when handling MMIO. This patch also adds support for injecting
memory mapped IPR requests into the memory system.
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The rflags register is spread across several different registers. Most
of the flags are stored in MISCREG_RFLAGS, but some are stored in
microcode registers. When accessing RFLAGS, we need to reconstruct it
from these registers. This changeset adds two functions,
X86ISA::getRFlags() and X86ISA::setRFlags(), that take care of this
magic.
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This changeset fixes two problems in the FABS and FCHS
implementation. First, the ISA parser expects the assignment in
flag_code to be a pure assignment and not an and-assignment, which
leads to the isa_parser omitting the misc reg update. Second, the FCHS
and FABS macro-ops don't set the SetStatus flag, which means that the
default micro-op version, which doesn't update FSW, is executed.
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This changeset adds the following stats to KVM:
* numVMHalfEntries: Number of entries into KVM to finalize pending
IO operations without executing guest instructions. These typically
happen as a result of a drain where the guest must finalize some
operations before the guest state is consistent.
* numExitSignal: Number of VM exits that have been triggered by a
signal. These usually happen as a result of the timer that limits
the time spent in KVM.
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We used to use the KVM CPU's clock to specify the host frequency. This
was not ideal for several reasons. One of them being that the clock
parameter of a CPU determines the frequency of some of the components
connected to the CPU. This changeset adds a separate hostFreq
parameter that should be used to specify the host frequency until we
add code to autodetect it. The hostFactor should still be used to
specify the conversion factor between the host performance and that of
the simulated system.
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We currently execute instructions in the guest and then handle any IO
request right after we break out of the virtualized environment. This
has the effect of executing IO requests in the exact same tick as the
first instruction in the sequence that was just run. There seem to be
cases where this simplification upsets some timing-sensitive devices.
This changeset splits execute and IO (and other services) across
multiple ticks. This is implemented by adding a separate
RunningService state to the CPU state machine. When a VM requires
service, it enters into this state and pending IO is then serviced in
the future instead of immediately. The delay between getting the
request and servicing it depends on the number of cycles executed in
the guest, which allows other components to catch up with the CPU.
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Update the system's totalNumInst counter when exiting from KVM and
maintain an internal absolute instruction count instead of relying on
the one from perf.
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The TSC value stored in MISCREG_TSC is actually just an offset from
the current CPU cycle to the actual TSC value. Writes with
side-effects to the TSC subtract the current cycle count before
storing the new value, while reads add the current cycle count. When
switching CPUs, the current value is copied without side-effects. This
works as long as the source and the destination CPUs have the same
clock frequencies. The TSC will jump, sometimes backwards, if they
have different clock frequencies. Most OSes assume the TSC to be
monotonic and break when this happens.
This changeset makes sure that the TSC is copied with side-effects to
ensure that the offset is updated to match the new CPU.
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HG changset 34e3295b0e39 introduced a check in the main simulation
loop that discards exit events that happen at the same tick as another
exit event. This was supposed to fix a problem where a simulation
script got confused by multiple exit events. This obviously breaks the
simulator since it can hide important simulation events, such as a
simulation failure, that happen at the same time as a non-fatal
simulation event.
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Currently, the only way to get a CPU to stop after a fixed number of
instructions/loads is to set a property on the CPU that causes a
SimLoopExitEvent to be scheduled when the CPU is constructed. This is
clearly not ideal in cases where the simulation script wants the CPU
to stop at multiple instruction counts (e.g., SimPoint generation).
This changeset adds the methods scheduleInstStop() and
scheduleLoadStop() to the BaseCPU. These methods are exported to
Python and are designed to be used from the simulation script. By
using these methods instead of the old properties, a simulation script
can schedule a stop at any point during simulation or schedule
multiple stops. The number of instructions specified when scheduling a
stop is relative to the current point of execution.
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This patch removes per processor cycle count, histogram for filter stats,
histogram for multicasts, histogram for prefetch wait, some function
prototypes that do not have definitions.
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The Profiler class does not need an event for dumping statistics
periodically. This is because there is a method for dumping statistics
for all the sim objects periodically. Since Ruby is a sim object, its
statistics are also included.
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This moves event and transition count statistics for cache controllers to
gem5's statistics. It does the same for the statistics associated with the
memory controller in ruby.
All the cache/directory/dma controllers individually collect the event and
transition counts. A callback function, collateStats(), has been added that
is invoked on the controller version 0 of each controller class. This
function adds all the individual controller statistics to a vector
variables. All the code for registering the statistical variables and
collating them is generated by SLICC. The patch removes the files
*_Profiler.{cc,hh} and *_ProfileDumper.{cc,hh} which were earlier used for
collecting and dumping statistics respectively.
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This patch adds a new flag to specify if the data values for a given vector
should be printed in one line in the stats.txt file. The default behavior
will be to print the data in multiple lines. It makes changes to print
functions to enforce this behavior.
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in the TLB
Some architectures (currently only x86) require some fixing-up of
physical addresses after a normal address translation. This is usually
to remap devices such as the APIC, but could be used for other memory
mapped devices as well. When running the CPU in a using hardware
virtualization, we still need to do these address fix-ups before
inserting the request into the memory system. This patch moves this
patch allows that code to be used by such CPUs without doing full
address translations.
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The custom Python loader didn't comply with PEP302 for two reasons:
* Previously, we would overwrite old modules on name
conflicts. PEP302 explicitly states that: "If there is an existing
module object named 'fullname' in sys.modules, the loader must use
that existing module".
* The "__package__" attribute wasn't set. PEP302: "The __package__
attribute must be set."
This changeset addresses both of these issues.
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Some architectures have special registers in the guest that can be
used to do cycle accounting. This is generally preferrable since the
prevents the guest from seeing a non-monotonic clock. This changeset
adds a virtual method, getHostCycles(), that the architecture-specific
code can override to implement this functionallity. The default
implementation uses the hwCycles counter.
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timer_create can apparently return -1 and set errno to EAGAIN if the
kernel suffered a temporary failure when allocating a timer. This
happens from time to time, so we need to handle it.
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It is now required to initialize the thread context by calling
startup() on it. Failing to do so currently causes decoder in
x86-based CPUs to get very confused when restoring from checkpoints.
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Some Linux versions disable updates (regB.set = 1) to prevent the chip
from updating its internal state while the OS is updating it. Support
for this was already there, this patch merely disables the check in
writeReg that prevented it from being enabled. The patch also includes
support for disabling the divider, which is used to control when clock
updates should start after setting the internal RTC state.
These changes are required to boot most vanilla Linux distributions
that update the RTC settings at boot.
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Rewrite reg A & B handling to use the bitunion stuff instead of bit
masking. Add better error messages when the kernel tries to enable
unsupported stuff.
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