Benchmarks

Cartesi Machine Benchmarks

This document presents performance benchmarks for the Cartesi Machine Emulator (CM) versions 0.18 and 0.19, compared with native execution and QEMU.

Design philosophy

Before reading the benchmark results, it is essential to understand the design philosophy of the Cartesi Machine Emulator, it's architected with the following fundamental goals:

1. Low complexity, for simplifying auditing processes and minimize the potential for errors.
2. Determinism, for bit-perfect computations reproducibility across different platforms.
3. Portability, for compatibility with various architectures (e.g., zkVMs, RISC-V RV32I).
4. Security, for providing strong guarantees of safe, sandboxed and correct execution of applications.
5. Verifiability, for enabling verification of state transitions during on-chain fraud proofs.

To achieve these objectives, the emulator adopts specific architectural decisions:

• No Just-In-Time (JIT) compilation, avoiding complexities and security issues.
• No floating-point hardware acceleration, as it can lead to non-deterministic results across different hardware.
• No multi-core interpretation, ensuring determinism and security.

Benchmark results

Stress Benchmark	CM 0.19	CM 0.18	QEMU	stress-ng command
Sieve Eratosthenes	22.30 ± 0.58	41.48 ± 1.15	5.59 ± 0.15	--cpu 1 --cpu-method sieve --cpu-ops 600
Fibonacci sequence	15.52 ± 0.16	30.27 ± 0.30	4.82 ± 0.33	--cpu 1 --cpu-method fibonacci --cpu-ops 500
Heapsort	12.81 ± 0.12	22.66 ± 0.36	6.67 ± 0.07	--heapsort 1 --heapsort-ops 5
JPEG compression	50.53 ± 1.89	76.74 ± 2.87	25.03 ± 0.94	--jpeg 1 --jpeg-ops 15
Zlib compression	7.82 ± 0.26	13.60 ± 0.45	4.01 ± 0.14	--zlib 1 --zlib-ops 30
Quicksort	18.38 ± 0.24	30.54 ± 0.20	10.29 ± 0.08	--qsort 1 --qsort-ops 8
Hashing functions	16.35 ± 0.38	29.98 ± 0.64	6.45 ± 0.14	--hash 1 --hash-ops 70000
SHA-256 hashing	41.48 ± 1.50	79.25 ± 3.26	19.87 ± 0.92	--crypt 1 --crypt-method SHA-256 --crypt-ops 500000
CPU int8 arithmetic	29.95 ± 0.92	59.24 ± 1.93	14.48 ± 0.45	--cpu 1 --cpu-method int8 --cpu-ops 700
CPU int32 arithmetic	28.46 ± 0.88	54.60 ± 1.64	13.95 ± 0.42	--cpu 1 --cpu-method int32 --cpu-ops 700
CPU int64 arithmetic	27.78 ± 0.36	54.35 ± 0.74	13.41 ± 0.17	--cpu 1 --cpu-method int64 --cpu-ops 700
CPU int128 arithmetic	20.34 ± 0.33	43.47 ± 0.78	6.99 ± 0.11	--cpu 1 --cpu-method int128 --cpu-ops 800
CPU float32 arithmetic	23.54 ± 0.34	35.03 ± 0.50	13.69 ± 0.20	--cpu 1 --cpu-method float --cpu-ops 600
CPU float64 arithmetic	35.81 ± 0.83	53.57 ± 1.24	19.18 ± 0.46	--cpu 1 --cpu-method double --cpu-ops 300
CPU looping	11.14 ± 0.12	24.17 ± 0.28	3.08 ± 0.03	--cpu 1 --cpu-method loop --cpu-ops 800
CPU NO-OP instruction	16.77 ± 0.22	37.46 ± 0.49	2.13 ± 0.04	--nop 1 --nop-ops 100000
CPU atomic operations	4.79 ± 0.22	4.90 ± 0.23	1.64 ± 0.08	--atomic 1 --atomic-ops 500
CPU branching prediction	2.99 ± 0.01	5.40 ± 0.05	10.37 ± 0.13	--branch 1 --branch-ops 300000
CPU cache trashing	14.63 ± 0.07	21.42 ± 0.08	8.42 ± 0.06	--cache 1 --cache-ops 150000
CPU cache line	47.42 ± 2.10	79.50 ± 3.53	12.22 ± 0.55	--cacheline 1 --cacheline-ops 125
CPU read cycle	96.83 ± 10.5	162.35 ± 17.7	14.91 ± 1.64	--clock 1 --clock-ops 2000
CPU pipeline execution	18.74 ± 0.32	22.23 ± 0.38	83.88 ± 2.18	--goto 1 --goto-ops 500000
CPU icache trashing	26.87 ± 0.86	22.22 ± 0.70	37.19 ± 1.22	--icache 1 --icache-ops 200
CPU icache branching	1.16 ± 0.01	1.22 ± 0.03	8.23 ± 0.09	--far-branch 1 --far-branch-ops 200
CPU registers read/write	5.34 ± 0.05	12.57 ± 0.59	1.09 ± 0.01	--regs 1 --regs-ops 15000
CPU function call	24.83 ± 0.50	44.69 ± 0.76	17.29 ± 0.31	--funccall 1 --funccall-ops 400
CPU bitwise arithmetic	38.40 ± 1.37	78.63 ± 2.83	15.22 ± 0.55	--cpu 1 --cpu-method bitops --cpu-ops 400
CPU page table and TLB	39.22 ± 0.96	39.56 ± 0.98	23.72 ± 0.66	--pagemove 1 --pagemove-ops 30
CPU TLB shootdown	18.48 ± 1.36	24.40 ± 1.80	11.11 ± 0.96	--tlb-shootdown 1 --tlb-shootdown-ops 2000
Memory copy	33.76 ± 0.84	64.19 ± 1.59	10.77 ± 0.27	--memcpy 1 --memcpy-ops 80
Memory read/write	12.14 ± 1.02	21.58 ± 0.79	4.19 ± 0.17	--memrate 1 --memrate-bytes 2M --memrate-ops 400
Memory mapping	21.45 ± 0.42	23.17 ± 0.49	14.35 ± 0.29	--mmap 1 --mmap-bytes 96M --mmap-ops 4
Memory and cache thrashing	6.54 ± 0.13	9.55 ± 0.19	9.76 ± 0.15	--randlist 1 --randlist-ops 250
Virtual memory page fault	19.76 ± 1.08	26.53 ± 1.46	19.71 ± 1.08	--fault 1 --fault-ops 10000
Virtual memory read/write	21.46 ± 0.86	37.28 ± 1.49	12.46 ± 0.50	--vm 1 --vm-bytes 96M --vm-ops 20000
Virtual memory addressing	20.63 ± 0.29	37.71 ± 0.50	6.67 ± 0.38	--vm-addr 1 --vm-addr-ops 20
Process forking	9.61 ± 0.23	11.14 ± 0.21	7.99 ± 0.23	--fork 1 --fork-ops 2000
Process context switching	9.42 ± 1.23	6.40 ± 0.83	12.32 ± 1.61	--switch 1 --switch-ops 200000
File read/write	20.31 ± 0.43	34.64 ± 0.73	6.14 ± 0.15	--hdd 1 --hdd-ops 6000
Threading	101.03 ± 4.24	115.29 ± 4.83	19.06 ± 0.82	--pthread 1 --pthread-ops 1500
Linux system calls	14.94 ± 0.95	14.30 ± 0.90	1.54 ± 0.10	--syscall 1 --syscall-ops 4000
Integer vector arithmetic	118.93 ± 8.70	126.12 ± 9.22	19.95 ± 1.47	--vecmath 1 --vecmath-ops 100
Integer wide vector arithmetic	165.38 ± 16.0	207.88 ± 20.1	45.03 ± 4.39	--vecwide 1 --vecwide-ops 600
Multi-precision floating-point	38.58 ± 0.83	54.01 ± 1.16	13.90 ± 0.33	--mpfr 1 --mpfr-ops 200
Floating-point square root	183.36 ± 29.42	348.78 ± 55.96	63.78 ± 10.30	--cpu 1 --cpu-method sqrt --cpu-ops 20
Floating-point FMA	101.68 ± 5.88	135.14 ± 7.61	36.92 ± 2.09	--fma 1 --fma-ops 100000
Floating-point math	110.51 ± 8.23	222.73 ± 16.7	52.28 ± 3.88	--fp 1 --fp-ops 150
Floating-point matmul	38.12 ± 0.92	49.40 ± 1.78	15.53 ± 0.38	--matrix 1 --matrix-method prod --matrix-ops 150
Floating-point trigonometric	97.03 ± 8.68	122.02 ± 10.9	43.83 ± 4.31	--trig 1 --trig-ops 80
Floating-point vector math	61.55 ± 5.05	107.38 ± 8.81	26.70 ± 2.24	--vecfp 1 --vecfp-ops 200

• Results are presented as mean ± standard deviation, representing the slowdown factor relative to native execution, meaning that lower is better.
• Bold entries indicate the best performance among the compared emulators.
• More information about each benchmark can be found at stress-ng manpage.

Benchmark methodology

• Benchmarks were conducted using the stress-ng tool, a stress workload generator designed to exercise various system components.
• Results are normalized against native host execution; lower values indicate better performance relative to native execution.
• Benchmarks compare CM versions 0.18, 0.19, and QEMU, providing insights into performance evolution and relative standing.
• Single-core limitation enforced on both host and guest environments.
• Identical guest kernel and root filesystem images were used.
• Each test includes the overhead of booting and shutting down the guest Linux OS.
• Benchmarks were repeated for statistical significance.

Performance analysis

1. Areas where CM outperforms QEMU

Despite generally slower performance due to its design philosophy, CM 0.19 notably outperforms QEMU in certain benchmarks:

• CPU branch prediction
• CPU pipeline execution
• CPU icache branching
• Memory and cache thrashing

These benchmarks are related to CPU branch prediction and CPU caching. The emulator's simpler execution model may lead to more predictable branch behavior and consistent memory access patterns, giving it an advantage over QEMU's more complex and dynamic optimizations.

2. Floating-point operations

Observations indicate significantly higher latency in all floating-point computations, especially in square roots due to the iterative nature of their implementation. This is a necessary trade-off to ensure determinism and portability through software-based emulation.

3. Vector and SIMD operations

Notable performance degradation is observed in benchmarks involving vector arithmetic and SIMD operations. This is consistent with the emulator's design priorities, which favor portability and simplicity over platform-specific optimizations.

4. Threading and parallelism

Higher overhead in threading benchmarks indicates less efficient context switching and thread management, and the single-core interpretation design impacts the ability to leverage multi-threaded workloads. This is a necessary trade-off due to the prioritized deterministic execution model.

Comparative insights

1. CM 0.19 vs. CM 0.18

CM 0.19 shows significant performance improvements over CM 0.18 across most benchmarks, reflecting advancements in the emulator's interpreter optimizations.

2. CM vs. QEMU

While QEMU generally outperforms CM due to its use of JIT compilation and allowance for non-deterministic optimizations, CM maintains respectable performance, often within a 2x slowdown factor relative to QEMU, despite its stricter design constraints.

Test environment

Hardware configuration

• Host CPU: Intel Core i9-14900K (x86_64)
• Host RAM: 64GB
• Guest CPU: rv64imafdc_zicntr_zicsr_zifencei_zihpm
• Guest RAM: 128MB (guest machine)

Software stack

• Host OS: Linux 6.6.65-1-lts
• Guest OS: Linux 6.5.13-ctsi-1
• QEMU: 9.1.2
• Cartesi Machine Emulator: 0.18.1 and 0.19.0 (pre-release)
• Compiler: GCC 14.2.1 20240910
• Benchmark tool: stress-ng 0.17.06
• Test date: 19/December/2024

Recommendations

• Developers should profile their applications to identify performance-critical sections that may be impacted by the emulator's limitations.
• Optimization strategies should include minimizing heavy floating-point computations where possible and exploring algorithmic optimizations that reduce reliance on vector operations.
• Given the single-core execution model, applications designed for parallel execution may need adjustments to align with the emulator's capabilities.

By aligning application design with the strengths of the Cartesi Machine Emulator, developers can effectively leverage its secure and deterministic environment for a wide range of computational tasks.