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arm: Fix v8 neon latency issue for loads/stores

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Neon memory ops that operate on multiple registers currently have very poor
performance because of interleave/deinterleave micro-ops.

This patch marks the deinterleave/interleave micro-ops as "No_OpClass" such
that they take minumum cycles to execute and are never resource constrained.

Additionaly the micro-ops over-read registers.  Although one form may need
to read up to 20 sources, not all do.  This adds in new forms so false
dependencies are not modeled.  Instructions read their minimum number of
sources.
This commit is contained in:
Mitch Hayenga 2014-09-03 07:42:44 -04:00
parent 4a3f11149d
commit bb1e6cf7c4
2 changed files with 56 additions and 15 deletions
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47
src/arch/arm/insts/macromem.cc
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2010-2013 ARM Limited
* Copyright (c) 2010-2014 ARM Limited
* All rights reserved
*
* The license below extends only to copyright in the software and shall
@ -1107,9 +1107,26 @@ VldMultOp64::VldMultOp64(const char *mnem, ExtMachInst machInst,
}
for (int i = 0; i < numMarshalMicroops; ++i) {
microOps[uopIdx++] = new MicroDeintNeon64(
machInst, vd + (RegIndex) (2 * i), vx, eSize, dataSize,
numStructElems, numRegs, i /* step */);
switch(numRegs) {
case 1: microOps[uopIdx++] = new MicroDeintNeon64_1Reg(
machInst, vd + (RegIndex) (2 * i), vx, eSize, dataSize,
numStructElems, 1, i /* step */);
break;
case 2: microOps[uopIdx++] = new MicroDeintNeon64_2Reg(
machInst, vd + (RegIndex) (2 * i), vx, eSize, dataSize,
numStructElems, 2, i /* step */);
break;
case 3: microOps[uopIdx++] = new MicroDeintNeon64_3Reg(
machInst, vd + (RegIndex) (2 * i), vx, eSize, dataSize,
numStructElems, 3, i /* step */);
break;
case 4: microOps[uopIdx++] = new MicroDeintNeon64_4Reg(
machInst, vd + (RegIndex) (2 * i), vx, eSize, dataSize,
numStructElems, 4, i /* step */);
break;
default: panic("Invalid number of registers");
}
}
assert(uopIdx == numMicroops);
@ -1150,9 +1167,25 @@ VstMultOp64::VstMultOp64(const char *mnem, ExtMachInst machInst,
unsigned uopIdx = 0;
for(int i = 0; i < numMarshalMicroops; ++i) {
microOps[uopIdx++] = new MicroIntNeon64(
machInst, vx + (RegIndex) (2 * i), vd, eSize, dataSize,
numStructElems, numRegs, i /* step */);
switch (numRegs) {
case 1: microOps[uopIdx++] = new MicroIntNeon64_1Reg(
machInst, vx + (RegIndex) (2 * i), vd, eSize, dataSize,
numStructElems, 1, i /* step */);
break;
case 2: microOps[uopIdx++] = new MicroIntNeon64_2Reg(
machInst, vx + (RegIndex) (2 * i), vd, eSize, dataSize,
numStructElems, 2, i /* step */);
break;
case 3: microOps[uopIdx++] = new MicroIntNeon64_3Reg(
machInst, vx + (RegIndex) (2 * i), vd, eSize, dataSize,
numStructElems, 3, i /* step */);
break;
case 4: microOps[uopIdx++] = new MicroIntNeon64_4Reg(
machInst, vx + (RegIndex) (2 * i), vd, eSize, dataSize,
numStructElems, 4, i /* step */);
break;
default: panic("Invalid number of registers");
}
}
uint32_t memaccessFlags = TLB::MustBeOne | (TLB::ArmFlags) eSize |

24
src/arch/arm/isa/insts/neon64_mem.isa
View file

@ -1,6 +1,6 @@
// -*- mode: c++ -*-
// Copyright (c) 2012-2013 ARM Limited
// Copyright (c) 2012-2014 ARM Limited
// All rights reserved
//
// The license below extends only to copyright in the software and shall
@ -163,11 +163,11 @@ let {{
header_output += MicroNeonMemDeclare64.subst(loadIop) + \
MicroNeonMemDeclare64.subst(storeIop)
def mkMarshalMicroOp(name, Name):
def mkMarshalMicroOp(name, Name, numRegs=4):
global header_output, decoder_output, exec_output
getInputCodeOp1L = ''
for v in range(4):
for v in range(numRegs):
for p in range(4):
getInputCodeOp1L += '''
writeVecElem(&input[%(v)d], (XReg) AA64FpOp1P%(p)dV%(v)d_uw,
@ -175,7 +175,7 @@ let {{
''' % { 'v' : v, 'p' : p }
getInputCodeOp1S = ''
for v in range(4):
for v in range(numRegs):
for p in range(4):
getInputCodeOp1S += '''
writeVecElem(&input[%(v)d], (XReg) AA64FpOp1P%(p)dV%(v)dS_uw,
@ -262,7 +262,8 @@ let {{
'''
iop = InstObjParams(name, Name, 'MicroNeonMixOp64',
{ 'code' : eCode }, ['IsMicroop'])
{ 'code' : eCode, 'op_class' : 'No_OpClass' },
['IsMicroop'])
header_output += MicroNeonMixDeclare64.subst(iop)
exec_output += MicroNeonMixExecute64.subst(iop)
@ -323,7 +324,8 @@ let {{
''' % { 'v': v, 'p': p}
iop = InstObjParams(name, Name, 'MicroNeonMixOp64',
{ 'code' : eCode }, ['IsMicroop'])
{ 'code' : eCode, 'op_class' : 'No_OpClass' },
['IsMicroop'])
header_output += MicroNeonMixDeclare64.subst(iop)
exec_output += MicroNeonMixExecute64.subst(iop)
@ -443,8 +445,14 @@ let {{
# Generate instructions
mkMemAccMicroOp('mem_neon_uop')
mkMarshalMicroOp('deint_neon_uop', 'MicroDeintNeon64')
mkMarshalMicroOp('int_neon_uop', 'MicroIntNeon64')
mkMarshalMicroOp('deint_neon_uop', 'MicroDeintNeon64_1Reg', numRegs=1)
mkMarshalMicroOp('deint_neon_uop', 'MicroDeintNeon64_2Reg', numRegs=2)
mkMarshalMicroOp('deint_neon_uop', 'MicroDeintNeon64_3Reg', numRegs=3)
mkMarshalMicroOp('deint_neon_uop', 'MicroDeintNeon64_4Reg', numRegs=4)
mkMarshalMicroOp('int_neon_uop', 'MicroIntNeon64_1Reg', numRegs=1)
mkMarshalMicroOp('int_neon_uop', 'MicroIntNeon64_2Reg', numRegs=2)
mkMarshalMicroOp('int_neon_uop', 'MicroIntNeon64_3Reg', numRegs=3)
mkMarshalMicroOp('int_neon_uop', 'MicroIntNeon64_4Reg', numRegs=4)
mkMarshalMicroOp('unpack_neon_uop', 'MicroUnpackNeon64')
mkMarshalMicroOp('pack_neon_uop', 'MicroPackNeon64')