Commit graph

13 commits

Author SHA1 Message Date
Radhika Jagtap
54519fd51f cpu: Support virtual addr in elastic traces
This patch adds support to optionally capture the virtual address and asid
for load/store instructions in the elastic traces. If they are present in
the traces, Trace CPU will set those fields of the request during replay.
2015-12-07 16:42:16 -06:00
Radhika Jagtap
3080bbcc36 cpu: Create record type enum for elastic traces
This patch replaces the booleans that specified the elastic trace record
type with an enum type. The source of change is the proto message for
elastic trace where the enum is introduced. The struct definitions in the
elastic trace probe listener as well as the Trace CPU replace the boleans
with the proto message enum.

The patch does not impact functionality, but traces are not compatible with
previous version. This is preparation for adding new types of records in
subsequent patches.
2015-12-07 16:42:16 -06:00
Radhika Jagtap
de4dc50e95 proto, probe: Add elastic trace probe to o3 cpu
The elastic trace is a type of probe listener and listens to probe points
in multiple stages of the O3CPU. The notify method is called on a probe
point typically when an instruction successfully progresses through that
stage.

As different listener methods mapped to the different probe points execute,
relevant information about the instruction, e.g. timestamps and register
accesses, are captured and stored in temporary InstExecInfo class objects.
When the instruction progresses through the commit stage, the timing and the
dependency information about the instruction is finalised and encapsulated in
a struct called TraceInfo. TraceInfo objects are collected in a list instead
of writing them out to the trace file one a time. This is required as the
trace is processed in chunks to evaluate order dependencies and computational
delay in case an instruction does not have any register dependencies. By this
we achieve a simpler algorithm during replay because every record in the
trace can be hooked onto a record in its past. The instruction dependency
trace is written out as a protobuf format file. A second trace containing
fetch requests at absolute timestamps is written to a separate protobuf
format file.

If the instruction is not executed then it is not added to the trace.
The code checks if the instruction had a fault, if it predicated
false and thus previous register values were restored or if it was a
load/store that did not have a request (e.g. when the size of the
request is zero). In all these cases the instruction is set as
executed by the Execute stage and is picked up by the commit probe
listener. But a request is not issued and registers are not written.
So practically, skipping these should not hurt the dependency modelling.

If squashing results in squashing younger instructions, it may happen that
the squash probe discards the inst and removes it from the temporary
store but execute stage deals with the instruction in the next cycle which
results in the execute probe seeing this inst as 'new' inst. A sequence
number of the last processed trace record is used to trap these cases and
not add to the temporary store.

The elastic instruction trace and fetch request trace can be read in and
played back by the TraceCPU.
2015-12-07 16:42:15 -06:00
Ali Saidi
4eff4fa12e cpu: add support for outputing a protobuf formatted CPU trace
Doesn't support x86 due to static instruction representation.

--HG--
rename : src/cpu/CPUTracers.py => src/cpu/InstPBTrace.py
2015-02-16 03:32:38 -05:00
Nilay Vaish
d07abd9b5b mem: change the namespace Message to ProtoMessage
The namespace Message conflicts with the Message data type used extensively
in Ruby.  Since Ruby is being moved to the same Master/Slave ports based
configuration style as the rest of gem5, this conflict needs to be resolved.
Hence, the namespace is being renamed to ProtoMessage.
2014-09-01 16:55:46 -05:00
Radhika Jagtap
c446dc40bd mem: Edit proto Packet and enhance the python script
This patch changes the decode script to output the optional fields of
the proto message Packet, namely id and flags. The flags field is set
by the communication monitor.

The id field is useful for CPU trace experiments, e.g. linking the
fetch side to decode side. It had to be renamed because it clashes
with a built in python function id() for getting the "identity" of an
object.

This patch also takes a few common function definitions out from the
multiple scripts and adds them to a protolib python module.
2014-03-07 15:56:23 -05:00
Andreas Hansson
4c7a283e55 base: Avoid size limitation on protobuf coded streams
This patch changes how the streams are created to avoid the size
limitation on the coded streams. As we only read/write a single
message at a time, there is never any message larger than a few
bytes. However, the coded stream eventually complains that its
internal counter reaches 64+ MByte if the total file size exceeds this
value.

Based on suggestions in the protobuf discussion forums, the coded
stream is now created for every message that is read/written. The
result is that the internal byte count never goes about tens of bytes,
and we can read/write any size file that the underlying file I/O can
handle.
2013-05-30 12:53:53 -04:00
Andreas Hansson
2123176684 mem: Add a generic id field to the packet trace
This patch adds an optional generic 64-bit identifier field to the
packet trace. This can be used to store the sequential number of the
instruction that gave rise to the packet, thread id, master id,
"sub"-master within a larger module etc. As the field is optional it
has a marginal cost if not used.
2013-03-26 14:46:45 -04:00
Andreas Hansson
7a57b1bce0 mem: Add optional request flags to the packet trace
This patch adds an optional flags field to the packet trace to encode
the request flags that contain information about whether the request
is (un)cacheable, instruction fetch, preftech etc.
2013-03-26 14:46:44 -04:00
Andreas Hansson
cbbc4c7f6b scons: Address clang 3.2 compilation error
This patch fixes a compilation error encountered using clang 3.2 on OSX.
2013-01-14 10:23:56 -05:00
Andreas Hansson
4afa6c4c3e base: Add wrapped protobuf input stream
This patch adds support for inputting protobuf messages through a
ProtoInputStream which hides the internal streams used by the
library. The stream is created based on the name of an input file and
optionally includes decompression using gzip.

The input stream will start by getting a magic number from the file,
and also verify that it matches with the expected value. Once opened,
messages can be read incrementally from the stream, returning
true/false until an error occurs or the end of the file is reached.
2013-01-07 13:05:37 -05:00
Andreas Hansson
f456c7983d mem: Add tracing support in the communication monitor
This patch adds packet tracing to the communication monitor using a
protobuf as the mechanism for creating the trace.

If no file is specified, then the tracing is disabled. If a file is
specified, then for every packet that is successfully sent, a protobuf
message is serialized to the file.
2013-01-07 13:05:37 -05:00
Andreas Hansson
11ab30fa5a base: Add wrapped protobuf output streams
This patch adds support for outputting protobuf messages through a
ProtoOutputStream which hides the internal streams used by the
library. The stream is created based on the name of an output file and
optionally includes compression using gzip.

The output stream will start by putting a magic number in the file,
and then for every message that is serialized prepend the size such
that the stream can be written and read incrementally. At this point
this merely serves as a proof of concept.
2013-01-07 13:05:37 -05:00