The WaitRec structure in the Process class is unnecessary. There
is a member declaration inside of the Process class, waitList,
that uses the WaitRec definition. However, waitList is unused so
they are both dead bits of code. This changeset removes both the
WaitRec struct and waitList member from Process.
Change-Id: Ia6ee7488b9f47fd0f0ae29c818fba6ea0710699c
Reviewed-on: https://gem5-review.googlesource.com/2262
Reviewed-by: Tony Gutierrez <anthony.gutierrez@amd.com>
Reviewed-by: Michael LeBeane <Michael.Lebeane@amd.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Modifies the clone system call and adds execve system call. Requires allowing
processes to steal thread contexts from other processes in the same system
object and the ability to detach pieces of process state (such as MemState)
to allow dynamic sharing.
This changeset adds functionality that allows system calls to retry without
affecting thread context state such as the program counter or register values
for the associated thread context (when system calls return with a retry
fault).
This functionality is needed to solve problems with blocking system calls
in multi-process or multi-threaded simulations where information is passed
between processes/threads. Blocking system calls can cause deadlock because
the simulator itself is single threaded. There is only a single thread
servicing the event queue which can cause deadlock if the thread hits a
blocking system call instruction.
To illustrate the problem, consider two processes using the producer/consumer
sharing model. The processes can use file descriptors and the read and write
calls to pass information to one another. If the consumer calls the blocking
read system call before the producer has produced anything, the call will
block the event queue (while executing the system call instruction) and
deadlock the simulation.
The solution implemented in this changeset is to recognize that the system
calls will block and then generate a special retry fault. The fault will
be sent back up through the function call chain until it is exposed to the
cpu model's pipeline where the fault becomes visible. The fault will trigger
the cpu model to replay the instruction at a future tick where the call has
a chance to succeed without actually going into a blocking state.
In subsequent patches, we recognize that a syscall will block by calling a
non-blocking poll (from inside the system call implementation) and checking
for events. When events show up during the poll, it signifies that the call
would not have blocked and the syscall is allowed to proceed (calling an
underlying host system call if necessary). If no events are returned from the
poll, we generate the fault and try the instruction for the thread context
at a distant tick. Note that retrying every tick is not efficient.
As an aside, the simulator has some multi-threading support for the event
queue, but it is not used by default and needs work. Even if the event queue
was completely multi-threaded, meaning that there is a hardware thread on
the host servicing a single simulator thread contexts with a 1:1 mapping
between them, it's still possible to run into deadlock due to the event queue
barriers on quantum boundaries. The solution of replaying at a later tick
is the simplest solution and solves the problem generally.
This changeset adds the ability to set a close-on-exec flag for a given
file descriptor. It also reworks some of the logic surrounding setting and
retrieving flags from the file description.
The traversal of drainable objects could potentially be
non-deterministic when using an unordered set containing object
pointers. To ensure that the iteration is deterministic, we switch to
a vector. Note that the lookup and traversal of the drainable objects
is not performance critical, so the change has no negative consequences.
Several large changes happen in this patch.
The FDEntry class is rewritten so that file descriptors now correspond to
types: 'File' which is normal file-backed file with the file open on the
host machine, 'Pipe' which is a pipe that has been opened on the host machine,
and 'Device' which does not have an open file on the host yet acts as a pseudo
device with which to issue ioctls. Other types which might be added in the
future are directory entries and sockets (off the top of my head).
The FDArray class was create to hold most of the file descriptor handling
that was stuffed into the Process class. It uses shared pointers and
the std::array type to hold the FDEntries mentioned above.
The changes to these two classes needed to be propagated out to the rest
of the code so there were quite a few changes for that. Also, comments were
added where I thought they were needed to help others and extend our
DOxygen coverage.
Moves aux_vector into its own .hh and .cc files just to get it out of the
already crowded Process files. Arguably, it could stay there, but it's
probably better just to move it and give it files.
The changeset looks ugly around the Process header file, but the goal here is
to move methods and members around so that they're not defined randomly
throughout the entire header file. I expect this is likely one of the reasons
why I several unused variables related to this class. So, the methods are
declared first followed by members. I've tried to aggregate them together
so that similar entries reside near one another.
There are other changes coming to this code so this is by no means the
final product.
The numCpus method is misleading in that it's not really a measure of
how many CPUs might be executing a process, but how many thread contexts
are assigned to the process at any given point in time.
It's nice to highlight this distinction because thread contexts are never
reused in the same way that a CPU can be reused for multiple processes.
The reason that there is no reuse is that there is no CPU scheduler for SE.
The tru64 code intends to use this method and the accompanying contextIDs
field to support SMT and track the number of threads with some system calls.
With the up coming clone and exec patches, this paradigm must change. There
needs to be a 1:1 mapping between the thread contexts and processes so that
the process state between threads is allowed to vary when needed by Linux.
This should not break SMT for tru64 if the Process class is refactored so that
multiple Processes can share state between themselves. The following patches
will do the refactoring incrementally as features are added.
It looks like tru64 has some nxm* system calls, but the two fields that
are defined in the Process class are unused by any of the code. There doesn't
appear to be any reference in the tru64 code.
The EIOProcess class was removed recently and it was the only other class
which derived from Process. Since every Process invocation is also a
LiveProcess invocation, it makes sense to simplify the organization by
combining the fields from LiveProcess into Process.
A KVM VM is typically a child of the System object already, but for
solving future issues with configuration graph resolution, the most
logical way to keep track of this object is for it to be an actual
parameter of the System object.
Change-Id: I965ded22203ff8667db9ca02de0042ff1c772220
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
The CxxConfigManager schould create objects by traversing the object tree
starting from the root object. However, currently objects are created in
aplphabetical order, which only works if the root object alphabetically
comes before any system object (e.g. 'root' < 'system'. Otherwise (e.g.
'a_system' < 'root'), object construction may fail. The reason for this
behaviour is, that the call to findObject() in the sorting code also
constructs the object if it is not yet existent. Then findTraversalOrder()
calls findObject("root") and subseqeuently calls findObject() on all the
children, and so on. However, the call to findTraversalOrder() is
redundant, since all objects are already created in alphabetical order.
This patch simply removes the alphabetical ordering, leading to the objects
being created starting from 'root'.
Reviewed at http://reviews.gem5.org/r/3778/
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
Seeing build breakage after brandon@11801:
[ CXX] X86/sim/process.cc -> .o build/X86/sim/process.cc:137:64:
error: field '_pid' is uninitialized when used here
[-Werror,-Wuninitialized] static_cast<PageTableBase *>(new
ArchPageTable(name(), _pid, system)) : ^ build/X86/sim/process.cc:138:64:
error: field '_pid' is uninitialized when used here
[-Werror,-Wuninitialized] static_cast<PageTableBase *>(new
FuncPageTable(name(), _pid))), ^ 2 errors generated.
Testing Done: Compiles now on FreeBSD 10 with clang.
Reviewed at http://reviews.gem5.org/r/3804/
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
See developers mailing list. Trying to unbreak statfs.
Testing Done:
Builds on FreeBSD now.
Reviewed at http://reviews.gem5.org/r/3803/
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
Python's header files set various compiler macros (e.g.,
_XOPEN_SOURCE) unconditionally. This triggers preprocessor warnings
that end up being treated as errors. The Python integration manual [1]
strongly recommends that Python.h is included before any system
header. The style guide used to mandate that Python.h is included
first in any file that needs it. This requirement was changed to
always include a source file's main header first, which ended up
triggering these errors.
This change updates the style checker to always include Python.h
before the main header file.
[1] https://docs.python.org/2/extending/extending.html
Change-Id: Id6a4f7fc64a336a8fd26691a0ca682abeb1d1579
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Pierre-Yves Péneau <pierre-yves.peneau@lirmm.fr>
Used cppclean to help identify useless includes and removed them. This
involved erroneously included headers, but also cases where forward
declarations could have been used rather than a full include.
The class was crammed into syscall_emul.hh which has tons of forward
declarations and template definitions. To clean it up a bit, moved the
class into separate files and commented the class with doxygen style
comments. Also, provided some encapsulation by adding some accessors and
a mutator.
The syscallreturn.hh file was renamed syscall_return.hh to make it consistent
with other similarly named files in the src/sim directory.
The DPRINTF_SYSCALL macro was moved into its own header file with the
include the Base and Verbose flags as well.
--HG--
rename : src/sim/syscallreturn.hh => src/sim/syscall_return.hh
The CountedDrainEvent event was used to keep track of objects that
required additional simulation to drain. It was removed as a part of
the great drain rewrite, but the declaration remained.
Change-Id: I767a3213669040d3f27e2afafa2e4a5bb997e325
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
The headers declared in export_method_cxx_predecls are redundant since a
SimObject's main header is automatically included.
Change-Id: Ied9e84630b36960e54efe91d16f8c66fba7e0da0
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
Reviewed-by: Joe Gross <joseph.gross@amd.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
When restoring from a checkpoint, the simulation used to use file handles from
the checkpoint. This disallows multiple separate restore simulations from using
separate input and output files and directories, and plays havoc when the
checkpointed file locations may have changed. Add handling to allow the command
line specified files to be used as input/output for the restored simulation
(Note: this is the similar functionality to FS mode for output and error).
First of five patches adding RISC-V to GEM5. This patch introduces the
base 64-bit ISA (RV64I) in src/arch/riscv for use with syscall emulation.
The multiply, floating point, and atomic memory instructions will be added
in additional patches, as well as support for more detailed CPU models.
The loader is also modified to be able to parse RISC-V ELF files, and a
"Hello world\!" example for RISC-V is added to test-progs.
Patch 2 will implement the multiply extension, RV64M; patch 3 will implement
the floating point (single- and double-precision) extensions, RV64FD;
patch 4 will implement the atomic memory instructions, RV64A, and patch 5
will add support for timing, minor, and detailed CPU models that is missing
from the first four patches (such as handling locked memory).
[Removed several unused parameters and imports from RiscvInterrupts.py,
RiscvISA.py, and RiscvSystem.py.]
[Fixed copyright information in RISC-V files copied from elsewhere that had
ARM licenses attached.]
[Reorganized instruction definitions in decoder.isa so that they are sorted
by opcode in preparation for the addition of ISA extensions M, A, F, D.]
[Fixed formatting of several files, removed some variables and
instructions that were missed when moving them to other patches, fixed
RISC-V Foundation copyright attribution, and fixed history of files
copied from other architectures using hg copy.]
[Fixed indentation of switch cases in isa.cc.]
[Reorganized syscall descriptions in linux/process.cc to remove large
number of repeated unimplemented system calls and added implmementations
to functions that have received them since it process.cc was first
created.]
[Fixed spacing for some copyright attributions.]
[Replaced the rest of the file copies using hg copy.]
[Fixed style check errors and corrected unaligned memory accesses.]
[Fix some minor formatting mistakes.]
Signed-off by: Alec Roelke
Signed-off by: Jason Lowe-Power <jason@lowepower.com>
This patch adds the ability for an application to request dist-gem5 to begin/
end synchronization using an m5 op. When toggling on sync, all nodes agree
on the next sync point based on the maximum of all nodes' ticks. CPUs are
suspended until the sync point to avoid sending network messages until sync has
been enabled. Toggling off sync acts like a global execution barrier, where
all CPUs are disabled until every node reaches the toggle off point. This
avoids tricky situations such as one node hitting a toggle off followed by a
toggle on before the other nodes hit the first toggle off.
Read() should not write anything when returning 0 (EOF).
This patch does not correct the same bug occuring for :
nbr_read=read(file, buf, nbytes)
When nbr_read<nbytes, nbytes bytes are copied into the virtual
RAM instead of nbr_read. If buf is smaller than nbytes, a
page fault occurs, even if buf is in fact bigger than nbr_read.
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
When loading a checkpoint, it's sometimes desirable to be able to test
whether an entry within a secion exists. This is currently done
automatically in the UNSERIALIZE_OPT_SCALAR macro, but it isn't
possible to do for arrays, containers, or enums. Instead of adding
even more macros, add a helper function (CheckpointIn::entryExists())
that tests for the presence of an entry.
Change-Id: I4b4646b03276b889fd3916efefff3bd552317dbc
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
The quiesce family of magic ops can be simplified by the inclusion of
quiesceTick() and quiesce() functions on ThreadContext. This patch also
gets rid of the FS guards, since suspending a CPU is also a valid
operation for SE mode.
this patch fixes issues with changeset 11593
use the host's pwrite() syscall for pwrite64Func(),
as opposed to pwrite64(), because pwrite64() does
not work well on all distros.
undo the enabling of fstatfs, as we will add this
in a separate pate.
This patch adds SMT support to the MinorCPU. Currently
RoundRobin or Random thread scheduling are supported.
Change-Id: I91faf39ff881af5918cca05051829fc6261f20e3
This patch changes how the embedded swig code is loaded to ensure that
gem5 works with swig 3.0.9. For Python 2.7 and above, swig 3.0.9 now
relies on importlib, and actually looks in the appropriate packages,
even for the wrapped C code. However, the swig wrapper does not
explicitly place the module in the right package (it just calls
Py_InitModule), and we have to take explicit action to ensure that the
swig code can be loaded. This patch adds the information to the
generated wrappers and the appropriate calls to set the context as
part of the swig initialisation.
Previous versions of swig used to fall back on looking in the global
namespace for the wrappers (and still do for Python 2.6), but
technically things should not work without the functionality in this
patch.
The use of array tuples, requires an explicit include of the array library
Change-Id: I06730051777a97edf80e41a5604184b387b12239
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
mathexpr.hh uses std::function<> but was not including the appropriate
header, which resulted in an error
build/ARM/sim/mathexpr.hh:51:18: error: 'function' in namespace 'std'
does not name a template type
typedef std::function<double(std::string)> EvalCallback;
This commit adds the missing include.
Change-Id: I6c01d77d4354c6de838538f137a38f75f9866166
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
A lot of objects seem to request no-op power transitions which
currently results in large amounts of warnings. These warnings are
benign and risk hiding more serious warnings. Make the warning a
warn_once to prevent console flooding.
Change-Id: I86c74b4224b167f14469250ef86ab69fde7a227e
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
This patch makes thermal models use the power figures
calculated by power models. Since there is a circular
dependency between power and thermal (and thermal was
pushed before) this patch closes that loop.
Change-Id: I8bd5acf6a5026fdbbcfac47e33d27397f24a6f7d
Reviewed-by: Stephan Diestelhorst <stephan.diestelhorst@arm.com>
This patch adds some basic support for power models in gem5.
The power interface is defined so it can interact with thermal
models as well. It implements a simple power evaluator that
can be used for simple power models that express power in the
form of a math expression. These expressions can use stats
within the same SimObject (or down its hierarchy) and some
magic variables such as "temp" for temperature.
In future patches we will extend this functionality to allow
slightly more complex expressions.
The model allows it to be extended to use other kinds of models.
Change-Id: I76752f9638b6815e229fd74cdcb7721a305cbc4b
The power stats are currently very noisy even if no power model has
been loaded. Silence stats that are either zero or nan.
Change-Id: I7d0220c2fcf01131084a219228f140cfaddaf95b
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
