[MCA][LSUnit] Correctly update the internal group flags on store barrier execution. Fixes PR48024.

adibiagio · tstellar · commit 973b95e0a845 · 2020-11-20T22:09:45.000-08:00
This is likely to be a regressigion introduced by my last refactoring of the LSUnit (commit 5578ec3). Before this patch, the "CurrentStoreBarrierGroupID" index was not correctly reset on store barrier executions. This was leading to unexpected crashes like the one reported as PR48024. (cherry picked from commit 0e20666)
diff --git a/llvm/lib/MCA/HardwareUnits/LSUnit.cpp b/llvm/lib/MCA/HardwareUnits/LSUnit.cpp
@@ -243,6 +243,8 @@ void LSUnit::onInstructionExecuted(const InstRef &IR) {
       CurrentStoreGroupID = 0;
     if (GroupID == CurrentLoadBarrierGroupID)
       CurrentLoadBarrierGroupID = 0;
+    if (GroupID == CurrentStoreBarrierGroupID)
+      CurrentStoreBarrierGroupID = 0;
   }
 }
 
diff --git a/llvm/test/tools/llvm-mca/X86/BtVer2/stmxcsr-ldmxcsr.s b/llvm/test/tools/llvm-mca/X86/BtVer2/stmxcsr-ldmxcsr.s
@@ -0,0 +1,104 @@
+# NOTE: Assertions have been autogenerated by utils/update_mca_test_checks.py
+# RUN: llvm-mca -mtriple=x86_64-unknown-unknown -mcpu=btver2 -timeline -timeline-max-iterations=3 < %s | FileCheck %s
+
+# Code snippet taken from PR48024.
+
+stmxcsr -4(%rsp)
+movl    $-24577, %eax    # imm = 0x9FFF
+andl    -4(%rsp), %eax
+movl    %eax, -8(%rsp)
+ldmxcsr -8(%rsp)
+retq
+
+# CHECK:      Iterations:        100
+# CHECK-NEXT: Instructions:      600
+# CHECK-NEXT: Total Cycles:      704
+# CHECK-NEXT: Total uOps:        600
+
+# CHECK:      Dispatch Width:    2
+# CHECK-NEXT: uOps Per Cycle:    0.85
+# CHECK-NEXT: IPC:               0.85
+# CHECK-NEXT: Block RThroughput: 3.0
+
+# CHECK:      Instruction Info:
+# CHECK-NEXT: [1]: #uOps
+# CHECK-NEXT: [2]: Latency
+# CHECK-NEXT: [3]: RThroughput
+# CHECK-NEXT: [4]: MayLoad
+# CHECK-NEXT: [5]: MayStore
+# CHECK-NEXT: [6]: HasSideEffects (U)
+
+# CHECK:      [1]    [2]    [3]    [4]    [5]    [6]    Instructions:
+# CHECK-NEXT:  1      1     1.00           *      U     stmxcsr	-4(%rsp)
+# CHECK-NEXT:  1      1     0.50                        movl	$-24577, %eax
+# CHECK-NEXT:  1      4     1.00    *                   andl	-4(%rsp), %eax
+# CHECK-NEXT:  1      1     1.00           *            movl	%eax, -8(%rsp)
+# CHECK-NEXT:  1      3     1.00    *             U     ldmxcsr	-8(%rsp)
+# CHECK-NEXT:  1      4     1.00                  U     retq
+
+# CHECK:      Resources:
+# CHECK-NEXT: [0]   - JALU0
+# CHECK-NEXT: [1]   - JALU1
+# CHECK-NEXT: [2]   - JDiv
+# CHECK-NEXT: [3]   - JFPA
+# CHECK-NEXT: [4]   - JFPM
+# CHECK-NEXT: [5]   - JFPU0
+# CHECK-NEXT: [6]   - JFPU1
+# CHECK-NEXT: [7]   - JLAGU
+# CHECK-NEXT: [8]   - JMul
+# CHECK-NEXT: [9]   - JSAGU
+# CHECK-NEXT: [10]  - JSTC
+# CHECK-NEXT: [11]  - JVALU0
+# CHECK-NEXT: [12]  - JVALU1
+# CHECK-NEXT: [13]  - JVIMUL
+
+# CHECK:      Resource pressure per iteration:
+# CHECK-NEXT: [0]    [1]    [2]    [3]    [4]    [5]    [6]    [7]    [8]    [9]    [10]   [11]   [12]   [13]
+# CHECK-NEXT: 1.50   1.50    -      -      -      -      -     3.00    -     2.00    -      -      -      -
+
+# CHECK:      Resource pressure by instruction:
+# CHECK-NEXT: [0]    [1]    [2]    [3]    [4]    [5]    [6]    [7]    [8]    [9]    [10]   [11]   [12]   [13]   Instructions:
+# CHECK-NEXT:  -      -      -      -      -      -      -      -      -     1.00    -      -      -      -     stmxcsr	-4(%rsp)
+# CHECK-NEXT: 0.50   0.50    -      -      -      -      -      -      -      -      -      -      -      -     movl	$-24577, %eax
+# CHECK-NEXT: 0.50   0.50    -      -      -      -      -     1.00    -      -      -      -      -      -     andl	-4(%rsp), %eax
+# CHECK-NEXT:  -      -      -      -      -      -      -      -      -     1.00    -      -      -      -     movl	%eax, -8(%rsp)
+# CHECK-NEXT:  -      -      -      -      -      -      -     1.00    -      -      -      -      -      -     ldmxcsr	-8(%rsp)
+# CHECK-NEXT: 0.50   0.50    -      -      -      -      -     1.00    -      -      -      -      -      -     retq
+
+# CHECK:      Timeline view:
+# CHECK-NEXT:                     0123456789
+# CHECK-NEXT: Index     0123456789          01234
+
+# CHECK:      [0,0]     DeER .    .    .    .   .   stmxcsr	-4(%rsp)
+# CHECK-NEXT: [0,1]     DeER .    .    .    .   .   movl	$-24577, %eax
+# CHECK-NEXT: [0,2]     .DeeeeER  .    .    .   .   andl	-4(%rsp), %eax
+# CHECK-NEXT: [0,3]     .D====eER .    .    .   .   movl	%eax, -8(%rsp)
+# CHECK-NEXT: [0,4]     . D===eeeER    .    .   .   ldmxcsr	-8(%rsp)
+# CHECK-NEXT: [0,5]     . DeeeeE--R    .    .   .   retq
+# CHECK-NEXT: [1,0]     .  D===eE--R   .    .   .   stmxcsr	-4(%rsp)
+# CHECK-NEXT: [1,1]     .  DeE-----R   .    .   .   movl	$-24577, %eax
+# CHECK-NEXT: [1,2]     .   D====eeeeER.    .   .   andl	-4(%rsp), %eax
+# CHECK-NEXT: [1,3]     .   D========eER    .   .   movl	%eax, -8(%rsp)
+# CHECK-NEXT: [1,4]     .    D=======eeeER  .   .   ldmxcsr	-8(%rsp)
+# CHECK-NEXT: [1,5]     .    D=eeeeE-----R  .   .   retq
+# CHECK-NEXT: [2,0]     .    .D=======eE--R .   .   stmxcsr	-4(%rsp)
+# CHECK-NEXT: [2,1]     .    .DeE---------R .   .   movl	$-24577, %eax
+# CHECK-NEXT: [2,2]     .    . D========eeeeER  .   andl	-4(%rsp), %eax
+# CHECK-NEXT: [2,3]     .    . D============eER .   movl	%eax, -8(%rsp)
+# CHECK-NEXT: [2,4]     .    .  D===========eeeER   ldmxcsr	-8(%rsp)
+# CHECK-NEXT: [2,5]     .    .  D=eeeeE---------R   retq
+
+# CHECK:      Average Wait times (based on the timeline view):
+# CHECK-NEXT: [0]: Executions
+# CHECK-NEXT: [1]: Average time spent waiting in a scheduler's queue
+# CHECK-NEXT: [2]: Average time spent waiting in a scheduler's queue while ready
+# CHECK-NEXT: [3]: Average time elapsed from WB until retire stage
+
+# CHECK:            [0]    [1]    [2]    [3]
+# CHECK-NEXT: 0.     3     4.3    1.0    1.3       stmxcsr	-4(%rsp)
+# CHECK-NEXT: 1.     3     1.0    1.0    4.7       movl	$-24577, %eax
+# CHECK-NEXT: 2.     3     5.0    0.3    0.0       andl	-4(%rsp), %eax
+# CHECK-NEXT: 3.     3     9.0    0.0    0.0       movl	%eax, -8(%rsp)
+# CHECK-NEXT: 4.     3     8.0    0.0    0.0       ldmxcsr	-8(%rsp)
+# CHECK-NEXT: 5.     3     1.7    1.7    5.3       retq
+# CHECK-NEXT:        3     4.8    0.7    1.9       <total>
diff --git a/llvm/test/tools/llvm-mca/X86/Haswell/stmxcsr-ldmxcsr.s b/llvm/test/tools/llvm-mca/X86/Haswell/stmxcsr-ldmxcsr.s
@@ -0,0 +1,100 @@
+# NOTE: Assertions have been autogenerated by utils/update_mca_test_checks.py
+# RUN: llvm-mca -mtriple=x86_64-unknown-unknown -mcpu=haswell -timeline -timeline-max-iterations=3 < %s | FileCheck %s
+
+# Code snippet taken from PR48024.
+
+stmxcsr -4(%rsp)
+movl    $-24577, %eax    # imm = 0x9FFF
+andl    -4(%rsp), %eax
+movl    %eax, -8(%rsp)
+ldmxcsr -8(%rsp)
+retq
+
+# CHECK:      Iterations:        100
+# CHECK-NEXT: Instructions:      600
+# CHECK-NEXT: Total Cycles:      1304
+# CHECK-NEXT: Total uOps:        1300
+
+# CHECK:      Dispatch Width:    4
+# CHECK-NEXT: uOps Per Cycle:    1.00
+# CHECK-NEXT: IPC:               0.46
+# CHECK-NEXT: Block RThroughput: 3.3
+
+# CHECK:      Instruction Info:
+# CHECK-NEXT: [1]: #uOps
+# CHECK-NEXT: [2]: Latency
+# CHECK-NEXT: [3]: RThroughput
+# CHECK-NEXT: [4]: MayLoad
+# CHECK-NEXT: [5]: MayStore
+# CHECK-NEXT: [6]: HasSideEffects (U)
+
+# CHECK:      [1]    [2]    [3]    [4]    [5]    [6]    Instructions:
+# CHECK-NEXT:  3      2     1.00           *      U     stmxcsr	-4(%rsp)
+# CHECK-NEXT:  1      1     0.25                        movl	$-24577, %eax
+# CHECK-NEXT:  2      6     0.50    *                   andl	-4(%rsp), %eax
+# CHECK-NEXT:  1      1     1.00           *            movl	%eax, -8(%rsp)
+# CHECK-NEXT:  3      7     1.00    *             U     ldmxcsr	-8(%rsp)
+# CHECK-NEXT:  3      7     1.00                  U     retq
+
+# CHECK:      Resources:
+# CHECK-NEXT: [0]   - HWDivider
+# CHECK-NEXT: [1]   - HWFPDivider
+# CHECK-NEXT: [2]   - HWPort0
+# CHECK-NEXT: [3]   - HWPort1
+# CHECK-NEXT: [4]   - HWPort2
+# CHECK-NEXT: [5]   - HWPort3
+# CHECK-NEXT: [6]   - HWPort4
+# CHECK-NEXT: [7]   - HWPort5
+# CHECK-NEXT: [8]   - HWPort6
+# CHECK-NEXT: [9]   - HWPort7
+
+# CHECK:      Resource pressure per iteration:
+# CHECK-NEXT: [0]    [1]    [2]    [3]    [4]    [5]    [6]    [7]    [8]    [9]
+# CHECK-NEXT:  -      -     1.75   1.74   1.67   1.68   2.00   1.75   1.76   1.65
+
+# CHECK:      Resource pressure by instruction:
+# CHECK-NEXT: [0]    [1]    [2]    [3]    [4]    [5]    [6]    [7]    [8]    [9]    Instructions:
+# CHECK-NEXT:  -      -      -      -     0.30    -     1.00   1.00    -     0.70   stmxcsr	-4(%rsp)
+# CHECK-NEXT:  -      -     0.08   0.67    -      -      -     0.04   0.21    -     movl	$-24577, %eax
+# CHECK-NEXT:  -      -     0.42   0.37   0.35   0.65    -     0.01   0.20    -     andl	-4(%rsp), %eax
+# CHECK-NEXT:  -      -      -      -     0.05    -     1.00    -      -     0.95   movl	%eax, -8(%rsp)
+# CHECK-NEXT:  -      -     1.00   0.23   0.34   0.66    -     0.42   0.35    -     ldmxcsr	-8(%rsp)
+# CHECK-NEXT:  -      -     0.25   0.47   0.63   0.37    -     0.28   1.00    -     retq
+
+# CHECK:      Timeline view:
+# CHECK-NEXT:                     0123456789          0123456789
+# CHECK-NEXT: Index     0123456789          0123456789          012
+
+# CHECK:      [0,0]     DeeER.    .    .    .    .    .    .    . .   stmxcsr	-4(%rsp)
+# CHECK-NEXT: [0,1]     DeE-R.    .    .    .    .    .    .    . .   movl	$-24577, %eax
+# CHECK-NEXT: [0,2]     .DeeeeeeER.    .    .    .    .    .    . .   andl	-4(%rsp), %eax
+# CHECK-NEXT: [0,3]     .D======eER    .    .    .    .    .    . .   movl	%eax, -8(%rsp)
+# CHECK-NEXT: [0,4]     . D=====eeeeeeeER   .    .    .    .    . .   ldmxcsr	-8(%rsp)
+# CHECK-NEXT: [0,5]     .  DeeeeeeeE----R   .    .    .    .    . .   retq
+# CHECK-NEXT: [1,0]     .   D====eeE----R   .    .    .    .    . .   stmxcsr	-4(%rsp)
+# CHECK-NEXT: [1,1]     .   DeE---------R   .    .    .    .    . .   movl	$-24577, %eax
+# CHECK-NEXT: [1,2]     .    D=========eeeeeeER  .    .    .    . .   andl	-4(%rsp), %eax
+# CHECK-NEXT: [1,3]     .    D===============eER .    .    .    . .   movl	%eax, -8(%rsp)
+# CHECK-NEXT: [1,4]     .    .D==============eeeeeeeER.    .    . .   ldmxcsr	-8(%rsp)
+# CHECK-NEXT: [1,5]     .    . DeeeeeeeE-------------R.    .    . .   retq
+# CHECK-NEXT: [2,0]     .    .  D=============eeE----R.    .    . .   stmxcsr	-4(%rsp)
+# CHECK-NEXT: [2,1]     .    .  DeE------------------R.    .    . .   movl	$-24577, %eax
+# CHECK-NEXT: [2,2]     .    .   D==================eeeeeeER    . .   andl	-4(%rsp), %eax
+# CHECK-NEXT: [2,3]     .    .   D========================eER   . .   movl	%eax, -8(%rsp)
+# CHECK-NEXT: [2,4]     .    .    D=======================eeeeeeeER   ldmxcsr	-8(%rsp)
+# CHECK-NEXT: [2,5]     .    .    .DeeeeeeeE----------------------R   retq
+
+# CHECK:      Average Wait times (based on the timeline view):
+# CHECK-NEXT: [0]: Executions
+# CHECK-NEXT: [1]: Average time spent waiting in a scheduler's queue
+# CHECK-NEXT: [2]: Average time spent waiting in a scheduler's queue while ready
+# CHECK-NEXT: [3]: Average time elapsed from WB until retire stage
+
+# CHECK:            [0]    [1]    [2]    [3]
+# CHECK-NEXT: 0.     3     6.7    1.0    2.7       stmxcsr	-4(%rsp)
+# CHECK-NEXT: 1.     3     1.0    1.0    9.3       movl	$-24577, %eax
+# CHECK-NEXT: 2.     3     10.0   0.3    0.0       andl	-4(%rsp), %eax
+# CHECK-NEXT: 3.     3     16.0   0.0    0.0       movl	%eax, -8(%rsp)
+# CHECK-NEXT: 4.     3     15.0   0.0    0.0       ldmxcsr	-8(%rsp)
+# CHECK-NEXT: 5.     3     1.0    1.0    13.0      retq
+# CHECK-NEXT:        3     8.3    0.6    4.2       <total>

Original file line number	Diff line number	Diff line change
`@@ -243,6 +243,8 @@ void LSUnit::onInstructionExecuted(const InstRef &IR) {`
`243`	`243`	`CurrentStoreGroupID = 0;`
`244`	`244`	`if (GroupID == CurrentLoadBarrierGroupID)`
`245`	`245`	`CurrentLoadBarrierGroupID = 0;`
	`246`	`+ if (GroupID == CurrentStoreBarrierGroupID)`
	`247`	`+ CurrentStoreBarrierGroupID = 0;`
`246`	`248`	`}`
`247`	`249`	`}`
`248`	`250`