This patch simplifies the packet by removing the broadcast flag and
instead more firmly relying on (and enforcing) the semantics of
transactions in the classic memory system, i.e. request packets are
routed from a master to a slave based on the address, and when they
are created they have neither a valid source, nor destination. On
their way to the slave, the request packet is updated with a source
field for all modules that multiplex packets from multiple master
(e.g. a bus). When a request packet is turned into a response packet
(at the final slave), it moves the potentially populated source field
to the destination field, and the response packet is routed through
any multiplexing components back to the master based on the
destination field.
Modules that connect multiplexing components, such as caches and
bridges store any existing source and destination field in the sender
state as a stack (just as before).
The packet constructor is simplified in that there is no longer a need
to pass the Packet::Broadcast as the destination (this was always the
case for the classic memory system). In the case of Ruby, rather than
using the parameter to the constructor we now rely on setDest, as
there is already another three-argument constructor in the packet
class.
In many places where the packet information was printed as part of
DPRINTFs, request packets would be printed with a numeric "dest" that
would always be -1 (Broadcast) and that field is now removed from the
printing.
This patch adds the necessary flags to the SConstruct and SConscript
files for compiling using clang 2.9 and later (on Ubuntu et al and OSX
XCode 4.2), and also cleans up a bunch of compiler warnings found by
clang. Most of the warnings are related to hidden virtual functions,
comparisons with unsigneds >= 0, and if-statements with empty
bodies. A number of mismatches between struct and class are also
fixed. clang 2.8 is not working as it has problems with class names
that occur in multiple namespaces (e.g. Statistics in
kernel_stats.hh).
clang has a bug (http://llvm.org/bugs/show_bug.cgi?id=7247) which
causes confusion between the container std::set and the function
Packet::set, and this is currently addressed by not including the
entire namespace std, but rather selecting e.g. "using std::vector" in
the appropriate places.
This command will be sent from the memory system (Ruby) to the LSQ of
an O3 CPU so that the LSQ, if it needs to, invalidates the address in
the request packet.
This adds the derived class FunctionalPacket to fix a long standing
deficiency in the Packet class where it was unable to handle finding data to
partially satisfy a functional access. Made this a derived class as
functional accesses are used only in certain contexts and to not add any
additional overhead to the existing Packet class.
This patch rpovides functional access support in Ruby. Currently only
the M5Port of RubyPort supports functional accesses. The support for
functional through the PioPort will be added as a separate patch.
The packet now identifies whether static or dynamic data has been allocated and
is used by Ruby to determine whehter to copy the data pointer into the ruby
request. Subsequently, Ruby can be told not to update phys memory when
receiving packets.
If we write back an exclusive copy, we now mark it
as such, so the cache receiving the writeback can
mark its copy as exclusive. This avoids some
unnecessary upgrade requests when a cache later
tries to re-acquire exclusive access to the block.
Corrects an oversight in cset f97b62be544f. The fix there only
failed queued SCUpgradeReq packets that encountered an
invalidation, which meant that the upgrade had to reach the L2
cache. To handle pending requests in the L1 we must similarly
fail StoreCondReq packets too.
Requires new "SCUpgradeReq" message that marks upgrades
for store conditionals, so downstream caches can fail
these when they run into invalidations.
See http://www.m5sim.org/flyspray/task/197
Only set the dirty bit when we actually write to a block
(not if we thought we might but didn't, as in a failed
SC or CAS). This requires makeing sure the dirty bit
stays set when we get an exclusive (writable) copy
in a cache-to-cache transfer from another owner, which
n turn requires copying the mem-inhibit flag from
timing-mode requests to their associated responses.
This frees up needed space for more public flags. Also:
- remove unused Request accessor methods
- make Packet use public Request accessors, so it need not be a friend
I did some of the flags and assertions wrong. Thanks to Brad Beckmann
for pointing this out. I should have run the opt regressions instead
of the fast. I also screwed up some of the logical functions in the Flags
class.
where we defer a response to a read from a far-away cache A, then later
defer a ReadExcl from a cache B on the same bus as us. We'll assert
MemInhibit in both cases, but in the latter case MemInhibit will keep
the invalidation from reaching cache A. This special response tells
cache A that it gets the block to satisfy its read, but must immediately
invalidate it.
--HG--
extra : convert_revision : f85c8b47bb30232da37ac861b50a6539dc81161b
Turns out DeferredSnoop isn't quite the right bit of info
we needed... see new comment in cache_impl.hh.
--HG--
extra : convert_revision : a38de8c1677a37acafb743b7074ef88b21d3b7be
- Add "deferred snoop" flag to Packet so upper-level caches
can distinguish whether lower-level cache request was
in-service or not at the time of the original snoop.
- Revamp response handling to properly handle deferred snoops
on non-cache-fill requests (i.e. upgrades).
- Make sure forwarded writebacks are kept in write buffer at
lower-level caches so they get snooped properly.
--HG--
extra : convert_revision : 17f8a3772a1ae31a16991a53f8225ddf54d31fc9
src/cpu/memtest/memtest.cc:
Need to set packet source field so that response from cache
doesn't run into assertion failure when copying source to dest.
src/mem/packet.hh:
Copy source field when copying packets.
Assert that source is valid before copying it to dest
when turning packets around.
--HG--
extra : convert_revision : 09e3cfda424aa89fe170e21e955b295746832bf8
timing mode still broken.
configs/example/memtest.py:
Revamp options.
src/cpu/memtest/memtest.cc:
No need for memory initialization.
No need to make atomic response... memory system should do that now.
src/cpu/memtest/memtest.hh:
MemTest really doesn't want to snoop.
src/mem/bridge.cc:
checkFunctional() cleanup.
src/mem/bus.cc:
src/mem/bus.hh:
src/mem/cache/base_cache.cc:
src/mem/cache/base_cache.hh:
src/mem/cache/cache.cc:
src/mem/cache/cache.hh:
src/mem/cache/cache_blk.hh:
src/mem/cache/cache_builder.cc:
src/mem/cache/cache_impl.hh:
src/mem/cache/coherence/coherence_protocol.cc:
src/mem/cache/coherence/coherence_protocol.hh:
src/mem/cache/coherence/simple_coherence.hh:
src/mem/cache/miss/SConscript:
src/mem/cache/miss/mshr.cc:
src/mem/cache/miss/mshr.hh:
src/mem/cache/miss/mshr_queue.cc:
src/mem/cache/miss/mshr_queue.hh:
src/mem/cache/prefetch/base_prefetcher.cc:
src/mem/cache/tags/fa_lru.cc:
src/mem/cache/tags/fa_lru.hh:
src/mem/cache/tags/iic.cc:
src/mem/cache/tags/iic.hh:
src/mem/cache/tags/lru.cc:
src/mem/cache/tags/lru.hh:
src/mem/cache/tags/split.cc:
src/mem/cache/tags/split.hh:
src/mem/cache/tags/split_lifo.cc:
src/mem/cache/tags/split_lifo.hh:
src/mem/cache/tags/split_lru.cc:
src/mem/cache/tags/split_lru.hh:
src/mem/packet.cc:
src/mem/packet.hh:
src/mem/physical.cc:
src/mem/physical.hh:
src/mem/tport.cc:
More major reorg. Seems to work for atomic mode now,
timing mode still broken.
--HG--
extra : convert_revision : 7e70dfc4a752393b911880ff028271433855ae87