This patch changes the default behaviour of the SystemXBar, adding a
snoop filter. With the recent updates to the snoop filter allocation
behaviour this change no longer causes problems for the regressions
without caches.
Change-Id: Ibe0cd437b71b2ede9002384126553679acc69cc1
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Tony Gutierrez <anthony.gutierrez@amd.com>
Disable the default snoop filter in the SystemXBar so that the
typical membus does not have a snoop filter by default. Instead,
add the snoop filter only when there are caches added to the system
(with the caches / l2cache options).
The underlying problem is that the snoop filter grows without
bounds (for now) if there are no caches to tell it that lines have
been evicted. This causes slow regression runs for all the atomic
regressions. This patch fixes this behaviour.
--HG--
extra : source : f97c20511828209757440839ed48d741d02d428f
The 01.hello-2T-smt test case for the O3 CPU didn't correctly setup
the number of threads before creating interrupt controllers, which
confused the constructor in BaseCPU. This changeset adds SMT support
to the test configuration infrastructure.
--HG--
rename : tests/configs/o3-timing.py => tests/configs/o3-timing-mt.py
rename : tests/quick/se/01.hello-2T-smt/ref/alpha/linux/o3-timing/config.ini => tests/quick/se/01.hello-2T-smt/ref/alpha/linux/o3-timing-mt/config.ini
rename : tests/quick/se/01.hello-2T-smt/ref/alpha/linux/o3-timing/simerr => tests/quick/se/01.hello-2T-smt/ref/alpha/linux/o3-timing-mt/simerr
rename : tests/quick/se/01.hello-2T-smt/ref/alpha/linux/o3-timing/simout => tests/quick/se/01.hello-2T-smt/ref/alpha/linux/o3-timing-mt/simout
rename : tests/quick/se/01.hello-2T-smt/ref/alpha/linux/o3-timing/stats.txt => tests/quick/se/01.hello-2T-smt/ref/alpha/linux/o3-timing-mt/stats.txt
This patch adds a parameter to the BaseCache to enable a read-only
cache, for example for the instruction cache, or table-walker cache
(not for x86). A number of checks are put in place in the code to
ensure a read-only cache does not end up with dirty data.
A follow-on patch adds suitable read requests to allow a read-only
cache to explicitly ask for clean data.
This patch introduces a few subclasses to the CoherentXBar and
NoncoherentXBar to distinguish the different uses in the system. We
use the crossbar in a wide range of places: interfacing cores to the
L2, as a system interconnect, connecting I/O and peripherals,
etc. Needless to say, these crossbars have very different performance,
and the clock frequency alone is not enough to distinguish these
scenarios.
Instead of trying to capture every possible case, this patch
introduces dedicated subclasses for the three primary use-cases:
L2XBar, SystemXBar and IOXbar. More can be added if needed, and the
defaults can be overridden.
This changes the default ARM system to a Versatile Express-like system that supports
2GB of memory and PCI devices and updates the default kernels/file-systems for
AArch64 ARM systems (64-bit) to support up to 32GB of memory and PCI devices. Some
platforms that are no longer supported have been pruned from the configuration files.
In addition a set of 64-bit ARM regressions have been added to the regression system.
This patch changes the name of the Bus classes to XBar to better
reflect the actual timing behaviour. The actual instances in the
config scripts are not renamed, and remain as e.g. iobus or membus.
As part of this renaming, the code has also been clean up slightly,
making use of range-based for loops and tidying up some comments. The
only changes outside the bus/crossbar code is due to the delay
variables in the packet.
--HG--
rename : src/mem/Bus.py => src/mem/XBar.py
rename : src/mem/coherent_bus.cc => src/mem/coherent_xbar.cc
rename : src/mem/coherent_bus.hh => src/mem/coherent_xbar.hh
rename : src/mem/noncoherent_bus.cc => src/mem/noncoherent_xbar.cc
rename : src/mem/noncoherent_bus.hh => src/mem/noncoherent_xbar.hh
rename : src/mem/bus.cc => src/mem/xbar.cc
rename : src/mem/bus.hh => src/mem/xbar.hh
This patch changes the default parameter value of conf_table_reported
to match the common case. It also simplifies the regression and config
scripts to reflect this change.
This patch adds the notion of voltage domains, and groups clock
domains that operate under the same voltage (i.e. power supply) into
domains. Each clock domain is required to be associated with a voltage
domain, and the latter requires the voltage to be explicitly set.
A voltage domain is an independently controllable voltage supply being
provided to section of the design. Thus, if you wish to perform
dynamic voltage scaling on a CPU, its clock domain should be
associated with a separate voltage domain.
The current implementation of the voltage domain does not take into
consideration cases where there are derived voltage domains running at
ratio of native voltage domains, as with the case where there can be
on-chip buck/boost (charge pumps) voltage regulation logic.
The regression and configuration scripts are updated with a generic
voltage domain for the system, and one for the CPUs.
This patch moves the instantiation of the memory controller outside
FSConfig and instead relies on the mem_ranges to pass the information
to the caller (e.g. fs.py or one of the regression scripts). The main
motivation for this change is to expose the structural composition of
the memory system and allow more tuning and configuration without
adding a large number of options to the makeSystem functions.
The patch updates the relevant example scripts to maintain the current
functionality. As the order that ports are connected to the memory bus
changes (in certain regresisons), some bus stats are shuffled
around. For example, what used to be layer 0 is now layer 1.
Going forward, options will be added to support the addition of
multi-channel memory controllers.
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.
This patch extends the existing system builders to also include a
syscall-emulation builder. This builder is deployed in all
syscall-emulation regressions that do not involve Ruby,
i.e. o3-timing, simple-timing and simple-atomic, as well as the
multi-processor regressions o3-timing-mp, simple-timing-mp and
simple-atomic-mp (the latter are only used by SPARC at this point).
The values chosen for the cache sizes match those that were used in
the existing config scripts (despite being on the large
side). Similarly, a mem_class parameter is added to the builder base
class to enable simple-atomic to use SimpleMemory and o3-timing to use
the default DDR3 configuration.
Due to the different order the ports are connected, the bus stats get
shuffled around for the multi-processor regressions. A separate patch
bumps the port indices. Besides this, all behaviour is exactly the
same.
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.
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.
This changeset adds support for initializing a KVM VM in the
BaseSystem test class and adds the following methods in run.py:
require_file -- Test if a file exists and abort/skip if not.
require_kvm -- Test if KVM support has been compiled into gem5 (i.e.,
BaseKvmCPU exists) and the KVM device exists on the
host.
This changeset adds a set of tests that stress the CPU switching
code. It adds the following test configurations:
* tsunami-switcheroo-full -- Alpha system (atomic, timing, O3)
* realview-switcheroo-atomic -- ARM system (atomic<->atomic)
* realview-switcheroo-timing -- ARM system (timing<->timing)
* realview-switcheroo-o3 -- ARM system (O3<->O3)
* realview-switcheroo-full -- ARM system (atomic, timing, O3)
Reference data is provided for the 10.linux-boot test case. All of the
tests trigger a CPU switch once per millisecond during the boot
process.
The in-order CPU model was not included in any of the tests as it does
not support CPU handover.
This patch generalises the address range resolution for the I/O cache
and I/O bridge such that they do not assume a single memory. The patch
involves adding a parameter to the system which is then defined based
on the memories that are to be visible from the I/O subsystem, whether
behind a cache or a bridge.
The change is needed to allow interleaved memory controllers in the
system.
Most of the test cases currently contain a large amount of duplicated
boiler plate code. This changeset introduces a set of classes that
encapsulates most of the functionality when setting up a test
configuration.
The following base classes are introduced:
* BaseSystem - Basic system configuration that can be used for both
SE and FS simulation.
* BaseFSSystem - Basic FS configuration uni-processor and multi-processor
configurations.
* BaseFSSystemUniprocessor - Basic FS configuration for uni-processor
configurations. This is provided as a way
to make existing test cases backwards
compatible.
Architecture specific implementations are provided for ARM, Alpha, and
X86.
