From 54eaf40b8f8bf523c03208f0ebab18ee7ea8c184 Mon Sep 17 00:00:00 2001 From: "Emilio G. Cota" Date: Wed, 16 Jan 2019 12:01:14 -0500 Subject: tcg/i386: enable dynamic TLB sizing MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Reviewed-by: Alex Bennée Signed-off-by: Emilio G. Cota Message-Id: <20190116170114.26802-4-cota@braap.org> Signed-off-by: Richard Henderson --- tcg/i386/tcg-target.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tcg/i386/tcg-target.h') diff --git a/tcg/i386/tcg-target.h b/tcg/i386/tcg-target.h index 94aa4cef7c..eb40312e67 100644 --- a/tcg/i386/tcg-target.h +++ b/tcg/i386/tcg-target.h @@ -27,7 +27,7 @@ #define TCG_TARGET_INSN_UNIT_SIZE 1 #define TCG_TARGET_TLB_DISPLACEMENT_BITS 31 -#define TCG_TARGET_IMPLEMENTS_DYN_TLB 0 +#define TCG_TARGET_IMPLEMENTS_DYN_TLB 1 #ifdef __x86_64__ # define TCG_TARGET_REG_BITS 64 -- cgit v1.2.3