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| author | Emilio G. Cota <cota@braap.org> | 2019-01-16 12:01:14 -0500 |
|---|---|---|
| committer | Richard Henderson <richard.henderson@linaro.org> | 2019-01-28 07:03:34 -0800 |
| commit | 54eaf40b8f8bf523c03208f0ebab18ee7ea8c184 (patch) | |
| tree | 81737ff7b8e93170392f6904c68ae5d776bb5178 /tcg/i386/tcg-target.inc.c | |
| parent | 86e1eff8bc31a88a089d05b16277eafd7a3cf95b (diff) | |
| download | qemu-54eaf40b8f8bf523c03208f0ebab18ee7ea8c184.zip | |
tcg/i386: enable dynamic TLB sizing
As the following experiments show, this series is a net perf gain,
particularly for memory-heavy workloads. Experiments are run on an
Intel(R) Xeon(R) Gold 6142 CPU @ 2.60GHz.
1. System boot + shudown, debian aarch64:
- Before (v3.1.0):
Performance counter stats for './die.sh v3.1.0' (10 runs):
9019.797015 task-clock (msec) # 0.993 CPUs utilized ( +- 0.23% )
29,910,312,379 cycles # 3.316 GHz ( +- 0.14% )
54,699,252,014 instructions # 1.83 insn per cycle ( +- 0.08% )
10,061,951,686 branches # 1115.541 M/sec ( +- 0.08% )
172,966,530 branch-misses # 1.72% of all branches ( +- 0.07% )
9.084039051 seconds time elapsed ( +- 0.23% )
- After:
Performance counter stats for './die.sh tlb-dyn-v5' (10 runs):
8624.084842 task-clock (msec) # 0.993 CPUs utilized ( +- 0.23% )
28,556,123,404 cycles # 3.311 GHz ( +- 0.13% )
51,755,089,512 instructions # 1.81 insn per cycle ( +- 0.05% )
9,526,513,946 branches # 1104.641 M/sec ( +- 0.05% )
166,578,509 branch-misses # 1.75% of all branches ( +- 0.19% )
8.680540350 seconds time elapsed ( +- 0.24% )
That is, a 4.4% perf increase.
2. System boot + shutdown, ubuntu 18.04 x86_64:
- Before (v3.1.0):
56100.574751 task-clock (msec) # 1.016 CPUs utilized ( +- 4.81% )
200,745,466,128 cycles # 3.578 GHz ( +- 5.24% )
431,949,100,608 instructions # 2.15 insn per cycle ( +- 5.65% )
77,502,383,330 branches # 1381.490 M/sec ( +- 6.18% )
844,681,191 branch-misses # 1.09% of all branches ( +- 3.82% )
55.221556378 seconds time elapsed ( +- 5.01% )
- After:
56603.419540 task-clock (msec) # 1.019 CPUs utilized ( +- 10.19% )
202,217,930,479 cycles # 3.573 GHz ( +- 10.69% )
439,336,291,626 instructions # 2.17 insn per cycle ( +- 14.14% )
80,538,357,447 branches # 1422.853 M/sec ( +- 16.09% )
776,321,622 branch-misses # 0.96% of all branches ( +- 3.77% )
55.549661409 seconds time elapsed ( +- 10.44% )
No improvement (within noise range). Note that for this workload,
increasing the time window too much can lead to perf degradation,
since it flushes the TLB *very* frequently.
3. x86_64 SPEC06int:
x86_64-softmmu speedup vs. v3.1.0 for SPEC06int (test set)
Host: Intel(R) Xeon(R) Gold 6142 CPU @ 2.60GHz (Skylake)
5.5 +------------------------------------------------------------------------+
| +-+ |
5 |-+.................+-+...............................tlb-dyn-v5.......+-|
| * * |
4.5 |-+.................*.*................................................+-|
| * * |
4 |-+.................*.*................................................+-|
| * * |
3.5 |-+.................*.*................................................+-|
| * * |
3 |-+......+-+*.......*.*................................................+-|
| * * * * |
2.5 |-+......*..*.......*.*.................................+-+*...........+-|
| * * * * * * |
2 |-+......*..*.......*.*.................................*..*...........+-|
| * * * * * * +-+ |
1.5 |-+......*..*.......*.*.................................*..*.*+-+.*+-+.+-|
| * * *+-+ * * +-+ *+-+ +-+ +-+ * * * * * * |
1 |++++-+*+*++*+*++*++*+*++*+*+++-+*+*+-++*+-++++-++++-+++*++*+*++*+*++*+++|
| * * * * * * * * * * * * * * * * * * * * * * * * * * |
0.5 +------------------------------------------------------------------------+
400.perlb401.bzip403.g429445.g456.hm462.libq464.h471.omn47483.xalancbgeomean
png: https://imgur.com/YRF90f7
That is, a 1.51x average speedup over the baseline, with a max speedup
of 5.17x.
Here's a different look at the SPEC06int results, using KVM as the baseline:
x86_64-softmmu slowdown vs. KVM for SPEC06int (test set)
Host: Intel(R) Xeon(R) Gold 6142 CPU @ 2.60GHz (Skylake)
25 +---------------------------------------------------------------------------+
| +-+ +-+ |
| * * +-+ v3.1.0 |
| * * +-+ tlb-dyn-v5 |
| * * * * +-+ |
20 |-+.................*.*.............................*.+-+......*.*........+-|
| * * * # # * * |
| +-+ * * * # # * * |
| * * * * * # # * * |
15 |-+......*.*........*.*.............................*.#.#......*.+-+......+-|
| * * * * * # # * #|# |
| * * * * +-+ * # # * +-+ |
| * * +-+ * * ++-+ +-+ * # # * # # +-+ |
| * * +-+ * * * ## *| +-+ * # # * # # +-+ |
10 |-+......*.*..*.+-+.*.*........*.##.......++-+.*.+-+*.#.#......*.#.#.*.*..+-|
| * * * +-+ * * * ## +-+ *# # * # #* # # +-+ * # # * * |
| * * * # # * * +-+ * ## * +-+ *# # * # #* # # * * * # # *+-+ |
| * * * # # * * * +-+ * ## * # # *# # * # #* # # * * * # # * ## |
5 |-+......*.+-+*.#.#.*.*..*.#.#.*.##.*.#.#.*#.#.*.#.#*.#.#.*.*..*.#.#.*.##.+-|
| * # #* # # * +-+* # # * ## * # # *# # * # #* # # * * * # # * ## |
| * # #* # # * # #* # # * ## * # # *# # * # #* # # * +-+* # # * ## |
| ++-+ * # #* # # * # #* # # * ## * # # *# # * # #* # # * # #* # # * ## |
|+++*#+#+*+#+#*+#+#+*+#+#*+#+#+*+##+*+#+#+*#+#+*+#+#*+#+#+*+#+#*+#+#+*+##+++|
0 +---------------------------------------------------------------------------+
400.perlbe401.bzi403.gc429445.go456.h462.libqu464.h471.omne4483.xalancbmgeomean
png: https://imgur.com/YzAMNEV
After this series, we bring down the average SPEC06int slowdown vs KVM
from 11.47x to 7.58x.
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <20190116170114.26802-4-cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'tcg/i386/tcg-target.inc.c')
| -rw-r--r-- | tcg/i386/tcg-target.inc.c | 28 |
1 files changed, 14 insertions, 14 deletions
diff --git a/tcg/i386/tcg-target.inc.c b/tcg/i386/tcg-target.inc.c index dbf8253718..4d84aea3a9 100644 --- a/tcg/i386/tcg-target.inc.c +++ b/tcg/i386/tcg-target.inc.c @@ -329,6 +329,7 @@ static inline int tcg_target_const_match(tcg_target_long val, TCGType type, #define OPC_ARITH_GvEv (0x03) /* ... plus (ARITH_FOO << 3) */ #define OPC_ANDN (0xf2 | P_EXT38) #define OPC_ADD_GvEv (OPC_ARITH_GvEv | (ARITH_ADD << 3)) +#define OPC_AND_GvEv (OPC_ARITH_GvEv | (ARITH_AND << 3)) #define OPC_BLENDPS (0x0c | P_EXT3A | P_DATA16) #define OPC_BSF (0xbc | P_EXT) #define OPC_BSR (0xbd | P_EXT) @@ -1641,7 +1642,7 @@ static inline void tcg_out_tlb_load(TCGContext *s, TCGReg addrlo, TCGReg addrhi, } if (TCG_TYPE_PTR == TCG_TYPE_I64) { hrexw = P_REXW; - if (TARGET_PAGE_BITS + CPU_TLB_BITS > 32) { + if (TARGET_PAGE_BITS + CPU_TLB_DYN_MAX_BITS > 32) { tlbtype = TCG_TYPE_I64; tlbrexw = P_REXW; } @@ -1649,6 +1650,15 @@ static inline void tcg_out_tlb_load(TCGContext *s, TCGReg addrlo, TCGReg addrhi, } tcg_out_mov(s, tlbtype, r0, addrlo); + tcg_out_shifti(s, SHIFT_SHR + tlbrexw, r0, + TARGET_PAGE_BITS - CPU_TLB_ENTRY_BITS); + + tcg_out_modrm_offset(s, OPC_AND_GvEv + trexw, r0, TCG_AREG0, + offsetof(CPUArchState, tlb_mask[mem_index])); + + tcg_out_modrm_offset(s, OPC_ADD_GvEv + hrexw, r0, TCG_AREG0, + offsetof(CPUArchState, tlb_table[mem_index])); + /* If the required alignment is at least as large as the access, simply copy the address and mask. For lesser alignments, check that we don't cross pages for the complete access. */ @@ -1658,20 +1668,10 @@ static inline void tcg_out_tlb_load(TCGContext *s, TCGReg addrlo, TCGReg addrhi, tcg_out_modrm_offset(s, OPC_LEA + trexw, r1, addrlo, s_mask - a_mask); } tlb_mask = (target_ulong)TARGET_PAGE_MASK | a_mask; - - tcg_out_shifti(s, SHIFT_SHR + tlbrexw, r0, - TARGET_PAGE_BITS - CPU_TLB_ENTRY_BITS); - tgen_arithi(s, ARITH_AND + trexw, r1, tlb_mask, 0); - tgen_arithi(s, ARITH_AND + tlbrexw, r0, - (CPU_TLB_SIZE - 1) << CPU_TLB_ENTRY_BITS, 0); - - tcg_out_modrm_sib_offset(s, OPC_LEA + hrexw, r0, TCG_AREG0, r0, 0, - offsetof(CPUArchState, tlb_table[mem_index][0]) - + which); /* cmp 0(r0), r1 */ - tcg_out_modrm_offset(s, OPC_CMP_GvEv + trexw, r1, r0, 0); + tcg_out_modrm_offset(s, OPC_CMP_GvEv + trexw, r1, r0, which); /* Prepare for both the fast path add of the tlb addend, and the slow path function argument setup. */ @@ -1684,7 +1684,7 @@ static inline void tcg_out_tlb_load(TCGContext *s, TCGReg addrlo, TCGReg addrhi, if (TARGET_LONG_BITS > TCG_TARGET_REG_BITS) { /* cmp 4(r0), addrhi */ - tcg_out_modrm_offset(s, OPC_CMP_GvEv, addrhi, r0, 4); + tcg_out_modrm_offset(s, OPC_CMP_GvEv, addrhi, r0, which + 4); /* jne slow_path */ tcg_out_opc(s, OPC_JCC_long + JCC_JNE, 0, 0, 0); @@ -1696,7 +1696,7 @@ static inline void tcg_out_tlb_load(TCGContext *s, TCGReg addrlo, TCGReg addrhi, /* add addend(r0), r1 */ tcg_out_modrm_offset(s, OPC_ADD_GvEv + hrexw, r1, r0, - offsetof(CPUTLBEntry, addend) - which); + offsetof(CPUTLBEntry, addend)); } /* |