This patch simplifies the address-range determination mechanism and
also unifies the naming across ports and devices. It further splits
the queries for determining if a port is snooping and what address
ranges it responds to (aiming towards a separation of
cache-maintenance ports and pure memory-mapped ports). Default
behaviours are such that most ports do not have to define isSnooping,
and master ports need not implement getAddrRanges.
This patch removes the inheritance of EventManager from the ports and
moves all responsibility for event queues to the owner. Eventually the
event manager should be the interface block, which could either be the
structural owner or a subblock like a LSQ in the O3 CPU for example.
This patch changes the functionalAccess member function in the cache
model such that it is aware of what port the access came from, i.e. if
it came from the CPU side or from the memory side. By adding this
information, it is possible to respect the 'forwardSnoops' flag for
snooping requests coming from the memory side and not forward
them. This fixes an outstanding issue with the IO bus getting accesses
that have no valid destination port and also cleans up future changes
to the bus model.
Check that we're not currently writing back an address the prefetcher is trying
to prefetch before issuing it. We previously checked the mshrQueue and the cache
itself, but forgot to check the writeBuffer. This fixes a memory corrucption
issue with an L2 prefetcher.
Even though the code is safe, compiler flags a warning here, which are treated as errors for fast/opt. I know it's redundant but it has no side effects and fixes the compile.
Prefetch requests issued from the L2 or below wouldn't check if valid data is
present higher in the system. If a prefetch into the L2 occured at the same
time as writeback from a higher-level cache the dirty data could be replaced
in by unmodified data in memory.
At the same time, rename the trace flags to debug flags since they
have broader usage than simply tracing. This means that
--trace-flags is now --debug-flags and --trace-help is now --debug-help
This change fixes the problem for all the cases we actively use. If you want to try
more creative I/O device attachments (E.g. sharing an L2), this won't work. You
would need another level of caching between the I/O device and the cache
(which you actually need anyway with our current code to make sure writes
propagate). This is required so that you can mark the cache in between as
top level and it won't try to send ownership of a block to the I/O device.
Asserts have been added that should catch any issues.
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.
Allow lower-level caches (e.g., L2 or L3) to pass exclusive
copies to higher levels (e.g., L1). This eliminates a lot
of unnecessary upgrade transactions on read-write sequences
to non-shared data.
Also some cleanup of MSHR coherence handling and multiple
bug fixes.
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.
On the config end, if a shared L2 is created for the system, it is
parameterized to have n sharers as defined by option.num_cpus. In addition to
making the cache sharing aware so that discriminating tag policies can make use
of context_ids to make decisions, I added an occupancy AverageStat and an occ %
stat to each cache so that you could know which contexts are occupying how much
cache on average, both in terms of blocks and percentage. Note that since
devices have context_id -1, having an array of occ stats that correspond to
each context_id will break here, so in FS mode I add an extra bucket for device
blocks. This bucket is explicitly not added in SE mode in order to not only
avoid ugliness in the stats.txt file, but to avoid broken stats (some formulas
break when a bucket is 0).
This prevents redundant prefetches from being issued, solving the
occasional 'needsExclusive && !blk->isWritable()' assertion failure
in cache_impl.hh that several people have run into.
Eliminates "prefetch_cache_check_push" flag, neither setting of
which really solved the problem.
Previously there was one per bus, which caused some coherence problems
when more than one decided to respond. Now there is just one on
the main memory bus. The default bus responder on all other buses
is now the downstream cache's cpu_side port. Caches no longer need
to do address range filtering; instead, we just have a simple flag
to prevent snoops from propagating to the I/O bus.
Apparently we broke it with the cache rewrite and never noticed.
Thanks to Bao Yungang <baoyungang@gmail.com> for a significant part
of these changes (and for inspiring me to work on the rest).
Some other overdue cleanup on the prefetch code too.
I think readData() and writeData() were used for Erik's compression
work, but that code is gone, these aren't called anymore, and they
don't even really do what their names imply.
the primary identifier for a hardware context should be contextId(). The
concept of threads within a CPU remains, in the form of threadId() because
sometimes you need to know which context within a cpu to manipulate.
I was asserting that the only reason you would defer targets is if
a write came in while you had an outstanding read miss, but there's
another case where you could get a read access after you've snooped
an invalidation and buffered it because it applies to a prior
outstanding miss.
Make OutputDirectory::resolve() private and change the functions using
resolve() to instead use create().
--HG--
extra : convert_revision : 36d4be629764d0c4c708cec8aa712cd15f966453
if a prior write miss arrived while an even earlier
read miss was still outstanding.
--HG--
extra : convert_revision : 4924e145829b2ecf4610b88d33f4773510c6801a
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
Don't mark upstream MSHR as pending if downstream MSHR is already in service.
--HG--
extra : convert_revision : e1c135ff00217291db58ce8a06ccde34c403d37f
Not so much noise on failed sends, and more complete
info when grepping a trace using an address.
--HG--
extra : convert_revision : 05a8261c9452072ca08b906200c6322b33e2b9f1
SimObjects not yet updated:
- Process and subclasses
- BaseCPU and subclasses
The SimObject(const std::string &name) constructor was removed. Subclasses
that still rely on that behavior must call the parent initializer as
: SimObject(makeParams(name))
--HG--
extra : convert_revision : d6faddde76e7c3361ebdbd0a7b372a40941c12ed
Make sure not to keep processing functional accesses
after they've been responded to.
Also use checkFunctional() return value instead of checking
packet command field where possible, mostly just for consistency.
--HG--
extra : convert_revision : 29fc76bc18731bd93a4ed05a281297827028ef75
creation and initialization now happens in python. Parameter objects
are generated and initialized by python. The .ini file is now solely for
debugging purposes and is not used in construction of the objects in any
way.
--HG--
extra : convert_revision : 7e722873e417cb3d696f2e34c35ff488b7bff4ed
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
If the invalidation beats the upgrade at a lower level
then the upgrade must be converted to a read exclusive
"in the field".
Restructure target list & deferred target list to
factor out some common code.
--HG--
extra : convert_revision : 7bab4482dd6c48efdb619610f0d3778c60ff777a
- 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
Note that we should *not* print pointer values in DPRINTFs as
these needlessly clutter tracediff output.
--HG--
extra : convert_revision : 25a448f1b3ac8d453a717a104ad6dc0112fb30bb
src/cpu/simple/timing.cc:
Fix another SC problem.
src/mem/cache/cache_impl.hh:
Forgot to call makeTimingResponse() on uncached timing responses.
--HG--
extra : convert_revision : 5a5a58ca2053e4e8de2133205bfd37de15eb4209
Stats pretty much line up with old code, except:
- bug in old code included L1 latency in L2 miss time, making it too high
- UniCoherence did cache-to-cache transfers even from non-owner caches,
so occasionally the icache would get a block from the dcache not the L2
- L2 can now receive ReadExReq from L1 since L1s have coherence
--HG--
extra : convert_revision : 5052c1a1767b5a662f30a88f16012165a73b791c
Change target overflow from assertion to warning.
src/mem/cache/cache_impl.hh:
Change target overflow from assertion to warning.
--HG--
extra : convert_revision : ceca990ed916bbf96dedd4836c40df522803f173
src/mem/cache/cache_impl.hh:
Handle grants with no packet.
src/mem/cache/miss/mshr.cc:
Fix MSHR snoop hit handling.
--HG--
extra : convert_revision : f365283afddaa07cb9e050b2981ad6a898c14451
sure we don't re-request bus prematurely. Use callback to
avoid calling sendRetry() recursively within recvTiming.
--HG--
extra : convert_revision : a907a2781b4b00aa8eb1ea7147afc81d6b424140
supposed to and make sure parameters have the right type.
Also make sure that any object that should be an intermediate
type has the right options set.
--HG--
extra : convert_revision : d56910628d9a067699827adbc0a26ab629d11e93
into vm1.(none):/home/stever/bk/newmem-cache2
configs/example/memtest.py:
Hand merge redundant changes.
--HG--
extra : convert_revision : a2e36be254bf052024f37bcb23b5209f367d37e1
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
