[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PATCH 3/5] tcg-i386: Swap order of TLB hit and miss paths.
|
From: |
Richard Henderson |
|
Subject: |
[Qemu-devel] [PATCH 3/5] tcg-i386: Swap order of TLB hit and miss paths. |
|
Date: |
Fri, 21 May 2010 09:03:02 -0700 |
Make fallthru be TLB hit and branch be TLB miss. Doing this
both improves branch prediction and will allow further cleanup.
Signed-off-by: Richard Henderson <address@hidden>
---
tcg/i386/tcg-target.c | 172 +++++++++++++++++++++++--------------------------
1 files changed, 80 insertions(+), 92 deletions(-)
diff --git a/tcg/i386/tcg-target.c b/tcg/i386/tcg-target.c
index 30c933c..0d85ec0 100644
--- a/tcg/i386/tcg-target.c
+++ b/tcg/i386/tcg-target.c
@@ -771,26 +771,21 @@ static void tcg_out_qemu_ld_direct(TCGContext *s, int
datalo, int datahi,
static void tcg_out_qemu_ld(TCGContext *s, const TCGArg *args,
int opc)
{
- int addr_reg, data_reg, data_reg2, r0, r1, mem_index, s_bits;
+ int addr_reg, addr_reg2 = 0;
+ int data_reg, data_reg2 = 0;
+ int r0, r1, mem_index, s_bits;
#if defined(CONFIG_SOFTMMU)
- uint8_t *label1_ptr, *label2_ptr;
-#endif
-#if TARGET_LONG_BITS == 64
-#if defined(CONFIG_SOFTMMU)
- uint8_t *label3_ptr;
-#endif
- int addr_reg2;
+ uint8_t *label_ptr[3];
#endif
data_reg = *args++;
- if (opc == 3)
+ if (opc == 3) {
data_reg2 = *args++;
- else
- data_reg2 = 0;
+ }
addr_reg = *args++;
-#if TARGET_LONG_BITS == 64
- addr_reg2 = *args++;
-#endif
+ if (TARGET_LONG_BITS == 64) {
+ addr_reg2 = *args++;
+ }
mem_index = *args;
s_bits = opc & 3;
@@ -815,28 +810,42 @@ static void tcg_out_qemu_ld(TCGContext *s, const TCGArg
*args,
tcg_out_mov(s, r0, addr_reg);
-#if TARGET_LONG_BITS == 32
- /* je label1 */
- tcg_out8(s, OPC_JCC_short + JCC_JE);
- label1_ptr = s->code_ptr;
- s->code_ptr++;
-#else
- /* jne label3 */
+ /* jne label1 */
tcg_out8(s, OPC_JCC_short + JCC_JNE);
- label3_ptr = s->code_ptr;
+ label_ptr[0] = s->code_ptr;
s->code_ptr++;
- /* cmp 4(r1), addr_reg2 */
- tcg_out_modrm_offset(s, OPC_CMP_GvEv, addr_reg2, r1, 4);
+ if (TARGET_LONG_BITS == 64) {
+ /* cmp 4(r1), addr_reg2 */
+ tcg_out_modrm_offset(s, OPC_CMP_GvEv, addr_reg2, r1, 4);
+
+ /* jne label1 */
+ tcg_out8(s, OPC_JCC_short + JCC_JNE);
+ label_ptr[1] = s->code_ptr;
+ s->code_ptr++;
+ }
+
+ /* TLB Hit. */
+
+ /* add x(r1), r0 */
+ tcg_out_modrm_offset(s, OPC_ADD_GvEv, r0, r1,
+ offsetof(CPUTLBEntry, addend) -
+ offsetof(CPUTLBEntry, addr_read));
+
+ tcg_out_qemu_ld_direct(s, data_reg, data_reg2, r0, 0, opc);
- /* je label1 */
- tcg_out8(s, OPC_JCC_short + JCC_JE);
- label1_ptr = s->code_ptr;
+ /* jmp label2 */
+ tcg_out8(s, OPC_JMP_short);
+ label_ptr[2] = s->code_ptr;
s->code_ptr++;
- /* label3: */
- *label3_ptr = s->code_ptr - label3_ptr - 1;
-#endif
+ /* TLB Miss. */
+
+ /* label1: */
+ *label_ptr[0] = s->code_ptr - label_ptr[0] - 1;
+ if (TARGET_LONG_BITS == 64) {
+ *label_ptr[1] = s->code_ptr - label_ptr[1] - 1;
+ }
/* XXX: move that code at the end of the TB */
#if TARGET_LONG_BITS == 32
@@ -876,23 +885,8 @@ static void tcg_out_qemu_ld(TCGContext *s, const TCGArg
*args,
break;
}
- /* jmp label2 */
- tcg_out8(s, OPC_JMP_short);
- label2_ptr = s->code_ptr;
- s->code_ptr++;
-
- /* label1: */
- *label1_ptr = s->code_ptr - label1_ptr - 1;
-
- /* add x(r1), r0 */
- tcg_out_modrm_offset(s, OPC_ADD_GvEv, r0, r1,
- offsetof(CPUTLBEntry, addend) -
- offsetof(CPUTLBEntry, addr_read));
-
- tcg_out_qemu_ld_direct(s, data_reg, data_reg2, r0, 0, opc);
-
/* label2: */
- *label2_ptr = s->code_ptr - label2_ptr - 1;
+ *label_ptr[2] = s->code_ptr - label_ptr[2] - 1;
#else
tcg_out_qemu_ld_direct(s, data_reg, data_reg2, addr_reg, GUEST_BASE, opc);
#endif
@@ -955,27 +949,22 @@ static void tcg_out_qemu_st_direct(TCGContext *s, int
datalo, int datahi,
static void tcg_out_qemu_st(TCGContext *s, const TCGArg *args,
int opc)
{
- int addr_reg, data_reg, data_reg2, r0, r1, mem_index, s_bits;
+ int addr_reg, addr_reg2 = 0;
+ int data_reg, data_reg2 = 0;
+ int r0, r1, mem_index, s_bits;
#if defined(CONFIG_SOFTMMU)
int stack_adjust;
- uint8_t *label1_ptr, *label2_ptr;
-#endif
-#if TARGET_LONG_BITS == 64
-#if defined(CONFIG_SOFTMMU)
- uint8_t *label3_ptr;
-#endif
- int addr_reg2;
+ uint8_t *label_ptr[3];
#endif
data_reg = *args++;
- if (opc == 3)
+ if (opc == 3) {
data_reg2 = *args++;
- else
- data_reg2 = 0;
+ }
addr_reg = *args++;
-#if TARGET_LONG_BITS == 64
- addr_reg2 = *args++;
-#endif
+ if (TARGET_LONG_BITS == 64) {
+ addr_reg2 = *args++;
+ }
mem_index = *args;
s_bits = opc;
@@ -1001,28 +990,42 @@ static void tcg_out_qemu_st(TCGContext *s, const TCGArg
*args,
tcg_out_mov(s, r0, addr_reg);
-#if TARGET_LONG_BITS == 32
- /* je label1 */
- tcg_out8(s, OPC_JCC_short + JCC_JE);
- label1_ptr = s->code_ptr;
- s->code_ptr++;
-#else
- /* jne label3 */
+ /* jne label1 */
tcg_out8(s, OPC_JCC_short + JCC_JNE);
- label3_ptr = s->code_ptr;
+ label_ptr[0] = s->code_ptr;
s->code_ptr++;
- /* cmp 4(r1), addr_reg2 */
- tcg_out_modrm_offset(s, OPC_CMP_GvEv, addr_reg2, r1, 4);
+ if (TARGET_LONG_BITS == 64) {
+ /* cmp 4(r1), addr_reg2 */
+ tcg_out_modrm_offset(s, OPC_CMP_GvEv, addr_reg2, r1, 4);
+
+ /* jne label1 */
+ tcg_out8(s, OPC_JCC_short + JCC_JNE);
+ label_ptr[1] = s->code_ptr;
+ s->code_ptr++;
+ }
+
+ /* TLB Hit. */
+
+ /* add x(r1), r0 */
+ tcg_out_modrm_offset(s, OPC_ADD_GvEv, r0, r1,
+ offsetof(CPUTLBEntry, addend) -
+ offsetof(CPUTLBEntry, addr_write));
+
+ tcg_out_qemu_st_direct(s, data_reg, data_reg2, r0, 0, opc);
- /* je label1 */
- tcg_out8(s, OPC_JCC_short + JCC_JE);
- label1_ptr = s->code_ptr;
+ /* jmp label2 */
+ tcg_out8(s, OPC_JMP_short);
+ label_ptr[2] = s->code_ptr;
s->code_ptr++;
- /* label3: */
- *label3_ptr = s->code_ptr - label3_ptr - 1;
-#endif
+ /* TLB Miss. */
+
+ /* label1: */
+ *label_ptr[0] = s->code_ptr - label_ptr[0] - 1;
+ if (TARGET_LONG_BITS == 64) {
+ *label_ptr[1] = s->code_ptr - label_ptr[1] - 1;
+ }
/* XXX: move that code at the end of the TB */
#if TARGET_LONG_BITS == 32
@@ -1080,23 +1083,8 @@ static void tcg_out_qemu_st(TCGContext *s, const TCGArg
*args,
tcg_out_addi(s, TCG_REG_ESP, stack_adjust);
}
- /* jmp label2 */
- tcg_out8(s, OPC_JMP_short);
- label2_ptr = s->code_ptr;
- s->code_ptr++;
-
- /* label1: */
- *label1_ptr = s->code_ptr - label1_ptr - 1;
-
- /* add x(r1), r0 */
- tcg_out_modrm_offset(s, OPC_ADD_GvEv, r0, r1,
- offsetof(CPUTLBEntry, addend) -
- offsetof(CPUTLBEntry, addr_write));
-
- tcg_out_qemu_st_direct(s, data_reg, data_reg2, r0, 0, opc);
-
/* label2: */
- *label2_ptr = s->code_ptr - label2_ptr - 1;
+ *label_ptr[2] = s->code_ptr - label_ptr[2] - 1;
#else
tcg_out_qemu_st_direct(s, data_reg, data_reg2, addr_reg, GUEST_BASE, opc);
#endif
--
1.7.0.1
- [Qemu-devel] [PATCH 0/5] tcg-i386: tidy softmmu code, Richard Henderson, 2010/05/21
- [Qemu-devel] [PATCH 1/5] tcg-i386: Tidy data16 prefixes., Richard Henderson, 2010/05/21
- [Qemu-devel] [PATCH 3/5] tcg-i386: Swap order of TLB hit and miss paths.,
Richard Henderson <=
- [Qemu-devel] [PATCH 2/5] tcg-i386: Split out TLB Hit path from qemu_ld/st., Richard Henderson, 2010/05/21
- [Qemu-devel] [PATCH 5/5] tcg-i386: Remove some ifdefs in qemu_ld/st., Richard Henderson, 2010/05/21
- [Qemu-devel] [PATCH 4/5] tcg-i386: Split out tlb load function., Richard Henderson, 2010/05/21
- Re: [Qemu-devel] [PATCH 0/5] tcg-i386: tidy softmmu code, Richard Henderson, 2010/05/21