Similar to horizontal ops on D56777, the sse2 (but not mmx) bit shift ops has local forwarding disabled, adding +1cy to the use latency for the result.
Differential Revision: https://reviews.llvm.org/D57026
llvm-svn: 351817
Similar to horizontal ops on D56777, the vpermilpd/vpermilps variable mask ops has local forwarding disabled, adding +1cy to the use latency for the result.
Differential Revision: https://reviews.llvm.org/D57022
llvm-svn: 351815
D56777 added +1cy local forwarding penalty for horizontal operations, but this penalty only affects sse2/xmm variants, the mmx variants don't suffer the penalty.
Confirmed with @andreadb
llvm-svn: 351755
r327630 introduced new write definitions for float/vector loads.
Before that revision, WriteLoad was used by both integer/float (scalar/vector)
load. So, WriteLoad had to conservatively declare a latency to 5cy. That is
because the load-to-use latency for float/vector load is 5cy.
Now that we have dedicated writes for float/vector loads, there is no reason why
we should keep the latency of WriteLoad to 5cy. At the moment, WriteLoad is only
used by scalar integer loads only; we can assume an optimstic 3cy latency for
them.
This patch changes that latency from 5cy to 3cy, and regenerates the affected
scheduling/mca tests.
Differential Revision: https://reviews.llvm.org/D56922
llvm-svn: 351742
On Jaguar, horizontal adds/subs have local forwarding disable.
That means, we pay a compulsory extra cycle of write-back stage, and the value
is not available until the end of that stage.
This patch changes the latency of horizontal operations by adding an extra
cycle. With this patch, latency numbers now match what is reported by perf.
I plan to send another patch to also 'fix' the latency of shuffle operations (on
Jaguar, local forwarding is disabled for vector shuffles too).
Differential Revision: https://reviews.llvm.org/D56777
llvm-svn: 351366
Class InstrBuilder wrongly assumed that llvm targets were always able to return
a non-null pointer when createMCInstrAnalysis() was called on them.
This was causing crashes when simulating executions for targets that don't
provide an MCInstrAnalysis object.
This patch fixes the issue by making MCInstrAnalysis optional.
llvm-svn: 349352
Refactor the scheduling predicates based on `MCInstPredicate`. In this
case, for the Exynos processors.
Differential revision: https://reviews.llvm.org/D55345
llvm-svn: 348774
It was failing as below. Adding a triple seems to help.
--
: 'RUN: at line 2'; /work/llvm.combined/build.release/bin/llvm-mca -march=aarch64 -mcpu=exynos-m1 -resource-pressure=false < /work/llvm.combined/llvm/test/tools/llvm-mca/AArch64/Exynos/direct-branch.s | /work/llvm.combined/build.release/bin/FileCheck /work/llvm.combined/llvm/test/tools/llvm-mca/AArch64/Exynos/direct-branch.s -check-prefixes=ALL,M1
: 'RUN: at line 3'; /work/llvm.combined/build.release/bin/llvm-mca -march=aarch64 -mcpu=exynos-m3 -resource-pressure=false < /work/llvm.combined/llvm/test/tools/llvm-mca/AArch64/Exynos/direct-branch.s | /work/llvm.combined/build.release/bin/FileCheck /work/llvm.combined/llvm/test/tools/llvm-mca/AArch64/Exynos/direct-branch.s -check-prefixes=ALL,M3
--
Exit Code: 1
Command Output (stderr):
--
/work/llvm.combined/llvm/test/tools/llvm-mca/AArch64/Exynos/direct-branch.s:36:12: error: M1-NEXT: expected string not found in input
^
<stdin>:21:2: note: scanning from here
1 0 0.25 b Ltmp0
^
--
llvm-svn: 348577
This patch adds the ability to specify via tablegen which processor resources
are load/store queue resources.
A new tablegen class named MemoryQueue can be optionally used to mark resources
that model load/store queues. Information about the load/store queue is
collected at 'CodeGenSchedule' stage, and analyzed by the 'SubtargetEmitter' to
initialize two new fields in struct MCExtraProcessorInfo named `LoadQueueID` and
`StoreQueueID`. Those two fields are identifiers for buffered resources used to
describe the load queue and the store queue.
Field `BufferSize` is interpreted as the number of entries in the queue, while
the number of units is a throughput indicator (i.e. number of available pickers
for loads/stores).
At construction time, LSUnit in llvm-mca checks for the presence of extra
processor information (i.e. MCExtraProcessorInfo) in the scheduling model. If
that information is available, and fields LoadQueueID and StoreQueueID are set
to a value different than zero (i.e. the invalid processor resource index), then
LSUnit initializes its LoadQueue/StoreQueue based on the BufferSize value
declared by the two processor resources.
With this patch, we more accurately track dynamic dispatch stalls caused by the
lack of LS tokens (i.e. load/store queue full). This is also shown by the
differences in two BdVer2 tests. Stalls that were previously classified as
generic SCHEDULER FULL stalls, are not correctly classified either as "load
queue full" or "store queue full".
About the differences in the -scheduler-stats view: those differences are
expected, because entries in the load/store queue are not released at
instruction issue stage. Instead, those are released at instruction executed
stage. This is the main reason why for the modified tests, the load/store
queues gets full before PdEx is full.
Differential Revision: https://reviews.llvm.org/D54957
llvm-svn: 347857
This change is in preparation for a patch that fixes PR36666.
llvm-mca currently doesn't know if a buffered processor resource describes a
load or store queue. So, any dynamic dispatch stall caused by the lack of
load/store queue entries is normally reported as a generic SCHEDULER stall. See for
example the -dispatch-stats output from the two tests modified by this patch.
In future, processor models will be able to tag processor resources that are
used to describe load/store queues. That information would then be used by
llvm-mca to correctly classify dynamic dispatch stalls caused by the lack of
tokens in the LS.
llvm-svn: 347662
Refactor the scheduling predicates based on `MCInstPredicate`. In this
case, `AArch64InstrInfo::hasShiftedReg()`.
Differential revision: https://reviews.llvm.org/D54820
llvm-svn: 347598
Refactor the scheduling predicates based on `MCInstPredicate`. In this
case, `AArch64InstrInfo::isScaledAddr()`
Differential revision: https://reviews.llvm.org/D54777
llvm-svn: 347597
By default, llvm-mca conservatively assumes that a register operand from the
variadic sequence is both a register read and a register write. That is because
MCInstrDesc doesn't describe extra variadic operands; we don't have enough
dataflow information to tell which register operands from the variadic sequence
is a definition, and which is a use instead.
However, if a variadic instruction is flagged 'mayStore' (but not 'mayLoad'),
and it has no 'unmodeledSideEffects', then llvm-mca (very) optimistically
assumes that any register operand in the variadic sequence is a register read
only. Conversely, if a variadic instruction is marked as 'mayLoad' (but not
'mayStore'), and it has no 'unmodeledSideEffects', then llvm-mca optimistically
assumes that any extra register operand is a register definition only.
These assumptions work quite well for variadic load/store multiple instructions
defined by the ARM backend.
llvm-svn: 347522
`llvm-mca` relies on the predicates to be based on `MCSchedPredicate` in order
to resolve the scheduling for variant instructions. Otherwise, it aborts
the building of the instruction model early.
However, the scheduling model emitter in `TableGen` gives up too soon, unless
all processors use only such predicates.
In order to allow more processors to be used with `llvm-mca`, this patch
emits scheduling transitions if any processor uses these predicates. The
transition emitted for the processors using legacy predicates is the one
specified with `NoSchedPred`, which is based on `MCSchedPredicate`.
Preferably, `llvm-mca` should instead assume a reasonable default when a
variant transition is not based on `MCSchedPredicate` for a given processor.
This issue should be revisited in the future.
Differential revision: https://reviews.llvm.org/D54648
llvm-svn: 347504
With this change, InstrBuilder emits an error if the MCInst sequence contains an
instruction with a variadic opcode, and a non-zero number of variadic operands.
Currently we don't know how to correctly analyze variadic opcodes. The problem
with variadic operands is that there is no information for them in the opcode
descriptor (i.e. MCInstrDesc). That means, we don't know which variadic operands
are defs, and which are uses.
In future, we could try to conservatively assume that any extra register
operands is both a register use and a register definition.
This patch fixes a subtle bug in the evaluation of read/write operands for ARM
VLD1 with implicit index update. Added test vld1-index-update.s
llvm-svn: 347503
RetireControlUnitStatistics now reports extra information about the ROB and the
avg/maximum number of entries consumed over the entire simulation.
Example:
Retire Control Unit - number of cycles where we saw N instructions retired:
[# retired], [# cycles]
0, 109 (17.9%)
1, 102 (16.7%)
2, 399 (65.4%)
Total ROB Entries: 64
Max Used ROB Entries: 35 ( 54.7% )
Average Used ROB Entries per cy: 32 ( 50.0% )
Documentation in llvm/docs/CommandGuide/llvmn-mca.rst has been updated to
reflect this change.
llvm-svn: 347493
This patch fixes an invalid memory read introduced by r346487.
Before this patch, partial register write had to query the latency of the
dependent full register write by calling a method on the full write descriptor.
However, if the full write is from an already retired instruction, chances are
that the EntryStage already reclaimed its memory.
In some parial register write tests, valgrind was reporting an invalid
memory read.
This change fixes the invalid memory access problem. Writes are now responsible
for tracking dependent partial register writes, and notify them in the event of
instruction issued.
That means, partial register writes no longer need to query their associated
full write to check when they are ready to execute.
Added test X86/BtVer2/partial-reg-update-7.s
llvm-svn: 347459
When looking at the tests committed by Roman at r346587, I noticed that numbers
reported by the resource pressure for PdAGU01 were wrong.
In particular, according to the aut-generated CHECK lines in tests
memcpy-like-test.s and store-throughput.s, resource pressure for PdAGU01
was not uniformly distributed among the two AGEN pipes.
It turns out that the reason why pressure was not correctly distributed, was
because the "resource selection strategy" object associated with PdAGU01 was not
correctly updated on the event of AGEN pipe used.
As a result, llvm-mca was not simulating a round-robin pipeline allocation for
PdAGU01. Instead, PdAGU1 was always prioritized over PdAGU0.
This patch fixes the issue; now processor resource strategy objects for
resources declaring multiple units, are correctly notified in the event of
"resource used".
llvm-svn: 346650
There are two AGU units, and per 1cy, there can be either two loads,
or a load and a store; but not two stores, or two loads and a store.
Additionally, loads shouldn't affect the store scheduler and vice versa.
(but *should* affect the PdEX scheduler.)
Required rL346545.
Fixes https://bugs.llvm.org/show_bug.cgi?id=39465
llvm-svn: 346587
As noted by Andrea Di Biagio in https://bugs.llvm.org/show_bug.cgi?id=39465
both the loads and stores occupy both the store and load queues.
This is clearly wrong.
llvm-svn: 346425
During review it was noted that while it appears that
the Piledriver can do two [consecutive] loads per cycle,
it can only do one store per cycle. It was suggested
that the sched model incorrectly models that,
but it was opted to fix this afterwards.
These tests show that the two consecutive loads are
modelled correctly, and one consecutive stores is not
modelled incorrectly. Unless i'm missing the point.
https://bugs.llvm.org/show_bug.cgi?id=39465
llvm-svn: 346404
This patch teaches view RegisterFileStatistics how to report events for
optimizable register moves.
For each processor register file, view RegisterFileStatistics reports the
following extra information:
- Number of optimizable register moves
- Number of register moves eliminated
- Number of zero moves (i.e. register moves that propagate a zero)
- Max Number of moves eliminated per cycle.
Differential Revision: https://reviews.llvm.org/D53976
llvm-svn: 345865
