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
I've put CMPXCHG8B/CMPXCHG16B in the same file, even though technically they are under separate CPUID bits all targets seem to support both (or neither).
llvm-svn: 338595
These aren't exhaustive, but cover some instructions that are only available in 32-bit mode (where would we be without good BCD math performance?).
llvm-svn: 338404
Before revision 336728, the "mayLoad" flag for instruction (V)MOVLPSrm was
inferred directly from the "default" pattern associated with the instruction
definition.
r336728 removed special node X86Movlps, and all the patterns associated to it.
Now instruction (V)MOVLPSrm doesn't have a pattern associated to it, and the
'mayLoad/hasSideEffects' flags are left unset.
When the instruction info is emitted by tablegen, method
CodeGenDAGPatterns::InferInstructionFlags() sees that (V)MOVLPSrm doesn't have a
pattern, and flags are undefined. So, it conservatively sets the
"hasSideEffects" flag for it.
As a consequence, we were losing the 'mayLoad' flag, and we were gaining a
'hasSideEffect' flag in its place.
This patch fixes the issue (originally reported by Michael Holmen).
The mca tests show the differences in the instruction info flags. Instructions
that were affected by this problem were: MOVLPSrm/VMOVLPSrm/VMOVLPSZ128rm.
Differential Revision: https://reviews.llvm.org/D49182
llvm-svn: 336818
This makes easier to identify changes in the instruction info flags. It also
helps spotting potential regressions similar to the one recently introduced at
r336728.
Using the same character to mark MayLoad/MayStore/HasSideEffects is problematic
for llvm-lit. When pattern matching substrings, llvm-lit consumes tabs and
spaces. A change in position of the flag marker may not trigger a test failure.
This patch only changes the character used for flag `hasSideEffects`. The reason
why I didn't touch other flags is because I want to avoid spamming the mailing
because of the massive diff due to the numerous tests affected by this change.
In future, each instruction flag should be associated with a different character
in the Instruction Info View.
llvm-svn: 336797
This patch teaches llvm-mca how to identify register writes that implicitly zero
the upper portion of a super-register.
On X86-64, a general purpose register is implemented in hardware as a 64-bit
register. Quoting the Intel 64 Software Developer's Manual: "an update to the
lower 32 bits of a 64 bit integer register is architecturally defined to zero
extend the upper 32 bits". Also, a write to an XMM register performed by an AVX
instruction implicitly zeroes the upper 128 bits of the aliasing YMM register.
This patch adds a new method named clearsSuperRegisters to the MCInstrAnalysis
interface to help identify instructions that implicitly clear the upper portion
of a super-register. The rest of the patch teaches llvm-mca how to use that new
method to obtain the information, and update the register dependencies
accordingly.
I compared the kernels from tests clear-super-register-1.s and
clear-super-register-2.s against the output from perf on btver2. Previously
there was a large discrepancy between the estimated IPC and the measured IPC.
Now the differences are mostly in the noise.
Differential Revision: https://reviews.llvm.org/D48225
llvm-svn: 335113
Summary:
I ran llvm-exegesis on SKX, SKL, BDW, HSW, SNB.
Atom is from Agner and SLM is a guess.
I've left AMD processors alone.
Reviewers: RKSimon, craig.topper
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D48079
llvm-svn: 335097
Summary:
Based on
* [[ https://support.amd.com/TechDocs/43479.pdf | AMD64 Architecture Programmer’s Manual Volume 6: 128-Bit and 256-Bit XOP and FMA4 Instructions ]],
* [[ https://support.amd.com/TechDocs/24594.pdf | AMD64 Architecture Programmer’s Manual Volume 3: General-Purpose and System Instructions]],
* https://en.wikipedia.org/wiki/XOP_instruction_set
Appears to be only supported in AMD's 15h generation, so only in b**d**ver[1-4],
for which currently llvm has no scheduling profiles.
Reviewers: RKSimon, craig.topper, andreadb, spatel
Reviewed By: RKSimon
Subscribers: gbedwell, llvm-commits
Differential Revision: https://reviews.llvm.org/D48264
llvm-svn: 335034
When the destination register of a XOP instruction is an XMM register, bits
[255:128] of the corresponding YMM register are cleared.
When the destination register of a EVEX encoded instruction is an XMM/YMM
register, the upper bits of the corresponding ZMM are cleared.
On processors that feature AVX512, a write to an XMM registers always clears the
upper portion of the corresponding ZMM register if the instruction is VEX or
EVEX encoded.
These new tests show some interesting cases which aren't correctly analyzed by
llvm-mca. The lack of knowledge related to the implicit update on the
super-registers is addressed by D48225.
llvm-svn: 334945
There are a lot of instructions to add under these ISAs (and the other AVX512 variants) but this should demonstrate how to test for the EVEX instructions with different maskings
llvm-svn: 334907
Added a Generic x86 cpu set of resource tests to allow us to check all ISAs.
We currently use SandyBridge as our generic CPU model, but it's better if we actually duplicate these tests for if/when we change the model, it also means we don't end up polluting the SandyBridge folder with tests for ISAs it doesn't support.
llvm-svn: 334853
Andrea Di Biagio