Commit Graph

69 Commits

Author SHA1 Message Date
Andrea Di Biagio fe3bc1b9bf [llvm-mca] Add extra counters for move elimination in view RegisterFileStatistics.
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
2018-11-01 18:04:39 +00:00
Fangrui Song 5a8fd65700 [llvm-mca] Move namespace mca inside llvm::
Summary: This allows to remove `using namespace llvm;` in those *.cpp files

When we want to revisit the decision (everything resides in llvm::mca::*) in the future, we can move things to a nested namespace of llvm::mca::, to conceptually make them separate from the rest of llvm::mca::*

Reviewers: andreadb, mattd

Reviewed By: andreadb

Subscribers: javed.absar, tschuett, gbedwell, llvm-commits

Differential Revision: https://reviews.llvm.org/D53407

llvm-svn: 345612
2018-10-30 15:56:08 +00:00
Sam McCall 0739ffc161 [llvm-mca] Fix -wreorder and -Wunused-private-field after r345376. NFC
llvm-svn: 345378
2018-10-26 12:19:48 +00:00
Andrea Di Biagio 84d0051310 [llvm-mca] Removed dependency on mca::SourcMgr in some Views. NFC
llvm-svn: 345376
2018-10-26 10:48:04 +00:00
Andrea Di Biagio 77c26aebda [llvm-mca] Removed a couple of redundant method declarations, and simplified code in ResourcePressureView. NFC
llvm-svn: 345259
2018-10-25 11:51:34 +00:00
Andrea Di Biagio 65c77d7283 [llvm-mca] Remove dependency from InstrBuilder in class InstructionTables.
Also, removed the initialization of vectors used for processor resource masks.
Support function 'computeProcResourceMasks()' already calls method resize on
those vectors.
No functional change intended.

llvm-svn: 345161
2018-10-24 16:56:43 +00:00
Andrea Di Biagio 7be45b0f85 [llvm-mca] Refactor class SourceMgr. NFCI
Added begin()/end() methods to allow the usage of SourceMgr in foreach loops.
With this change, method getMCInstFromIndex() (as well as a couple of other
methods) are now redundant, and can be removed from the public interface.

llvm-svn: 345147
2018-10-24 15:06:27 +00:00
Andrea Di Biagio db158be646 [llvm-mca] Remove a couple of using directives and a bunch of redundant namespace llvm prefixes. NFC
llvm-svn: 344916
2018-10-22 16:28:07 +00:00
Andrea Di Biagio b7f120f071 [llvm-mca] Remove method RegisterFileStatistics::initializeRegisterFileInfo(). NFC
llvm-svn: 344339
2018-10-12 12:38:27 +00:00
Matt Davis db834837c2 [llvm-mca] Delay calculation of Cycles per Resources, separate the cycles and resource quantities.
Summary:
This patch removes the storing of accumulated floating point data 
within the llvm-mca library.

This patch splits-up the two quantities: cycles and number of resource units.
By splitting-up these two quantities, we delay the calculation of "cycles per resource unit"
until that value is read, reducing the chance of accumulating floating point error. 

I considered using the APFloat, but after measuring performance, for a large (many iteration)
sample, I decided to go with this faster solution.

Reviewers: andreadb, courbet, RKSimon

Reviewed By: andreadb

Subscribers: llvm-commits, javed.absar, tschuett, gbedwell

Differential Revision: https://reviews.llvm.org/D51903

llvm-svn: 341980
2018-09-11 18:47:48 +00:00
Andrea Di Biagio 7f2230ff16 [llvm-mca] correctly initialize field 'CycleRetired' in the TimelineView.
This fixes a [-Wmissing-field-initializers] warning reported by buildbot
lld-x86_64-darwin13, build #25152.

llvm-svn: 341056
2018-08-30 11:17:58 +00:00
Andrea Di Biagio 8b647dcf4b [llvm-mca] Report the number of dispatched micro opcodes in the DispatchStatistics view.
This patch introduces the following changes to the DispatchStatistics view:
 * DispatchStatistics now reports the number of dispatched opcodes instead of
   the number of dispatched instructions.
 * The "Dynamic Dispatch Stall Cycles" table now also reports the percentage of
   stall cycles against the total simulated cycles.

This change allows users to easily compare dispatch group sizes with the
processor DispatchWidth.
Before this change, it was difficult to correlate the two numbers, since
DispatchStatistics view reported numbers of instructions (instead of opcodes).
DispatchWidth defines the maximum size of a dispatch group in terms of number of
micro opcodes.

The other change introduced by this patch is related to how DispatchStage
generates "instruction dispatch" events.
In particular:
 * There can be multiple dispatch events associated with a same instruction
 * Each dispatch event now encapsulates the number of dispatched micro opcodes.

The number of micro opcodes declared by an instruction may exceed the processor
DispatchWidth. Therefore, we cannot assume that instructions are always fully
dispatched in a single cycle.
DispatchStage knows already how to handle instructions declaring a number of
opcodes bigger that DispatchWidth. However, DispatchStage always emitted a
single instruction dispatch event (during the first simulated dispatch cycle)
for instructions dispatched.

With this patch, DispatchStage now correctly notifies multiple dispatch events
for instructions that cannot be dispatched in a single cycle.

A few views had to be modified. Views can no longer assume that there can only
be one dispatch event per instruction.

Tests (and docs) have been updated.

Differential Revision: https://reviews.llvm.org/D51430

llvm-svn: 341055
2018-08-30 10:50:20 +00:00
Andrea Di Biagio a2eee47450 [llvm-mca] Add fields "Total uOps" and "uOps Per Cycle" to the report generated by the SummaryView.
This patch adds two new fields to the perf report generated by the SummaryView.
Fields are now logically organized into two small groups; only the second group
contains throughput indicators.

Example:
```
Iterations:        100
Instructions:      300
Total Cycles:      414
Total uOps:        700

Dispatch Width:    4
uOps Per Cycle:    1.69
IPC:               0.72
Block RThroughput: 4.0
```

This patch also updates the docs for llvm-mca.
Due to the nature of this change, several tests in the tools/llvm-mca directory
were affected, and had to be updated using script `update_mca_test_checks.py`.

llvm-svn: 340946
2018-08-29 17:56:39 +00:00
Andrea Di Biagio 4269d64b20 [llvm-mca] Initialize each element in vector TimelineView::UsedBuffers to a default invalid buffer descriptor. NFCI
Also change the default buffer size for UsedBuffer entries to -1 (i.e. "unknown
size"). No functional change intended.

llvm-svn: 340830
2018-08-28 15:07:11 +00:00
Andrea Di Biagio d17d371c40 [llvm-mca][TimelineView] Force the same number of executions for every entry in the 'wait-times' table.
This patch also uses colors to highlight problematic wait-time entries.
A problematic entry is an entry with an high wait time that tends to match (or
exceed) the size of the scheduler's buffer.

Color RED is used if an instruction had to wait an average number of cycles
which is bigger than (or equal to) the size of the underlying scheduler's
buffer.
Color YELLOW is used if the time (in cycles) spend waiting for the
operands or pipeline resources is bigger than half the size of the underlying
scheduler's buffer.
Color MAGENTA is used if an instruction does not consume buffer resources
according to the scheduling model.

llvm-svn: 340825
2018-08-28 14:27:01 +00:00
Andrea Di Biagio 29c5d5aa36 [llvm-mca] Pass an instruction reference when notifying event listeners about reserved/released buffer resources. NFC
llvm-svn: 340821
2018-08-28 13:14:42 +00:00
Andrea Di Biagio 1a87a80d2f [llvm-mca] Remove unused include. NFC
llvm-svn: 340768
2018-08-27 19:14:35 +00:00
Andrea Di Biagio b89b96c1b2 [llvm-mca] Improved report generated by the SchedulerStatistics view.
Before this patch, the SchedulerStatistics only printed the maximum number of
buffer entries consumed in each scheduler's queue at a given point of the
simulation.

This patch restructures the reported table, and adds an extra field named
"Average number of used buffer entries" to it.
This patch also uses different colors to help identifying bottlenecks caused by
high scheduler's buffer pressure.

llvm-svn: 340746
2018-08-27 14:52:52 +00:00
Matt Davis 10aa09f008 [llvm-mca] Move views and stats into a Views subdir. NFC.
llvm-svn: 340645
2018-08-24 20:24:53 +00:00