Evaluating Spec CPU2026

5 hours ago

SPEC CPU2026 is the latest update to the SPEC CPU benchmark suite, featuring 52 workloads, up from 43 in SPEC CPU2017, with increased source code complexity (KLOC).
The reference system for SPEC CPU2026 is an Ampere eMAG 8180, which is outdated and easily outperformed by modern desktop CPUs like Intel's Lion Cove and AMD's Zen 5.
Performance analysis shows Zen 5 and Lion Cove are closely matched in integer tests, while Zen 5 often leads in floating point tests, partly due to AVX-512 support in GCC 14.2.0.
SPEC CPU2026 integer workloads generally have higher and tighter IPC (Instructions Per Cycle) distributions compared to SPEC CPU2017, indicating fewer cache misses and branch mispredicts, with less emphasis on branch prediction challenges.
Top-down analysis reveals improved retiring slot utilization in integer workloads, with frontend latency limiting performance in code compilation tests like 721.gcc and 723.llvm, while floating point workloads focus more on core throughput.
Instruction caching is more challenging in SPEC CPU2026, with larger code footprints reducing micro-op cache coverage on Zen 5, while Lion Cove's larger instruction cache handles misses better, and data-side cache misses are less common overall.
The suite lacks some low-IPC workloads like 520.omnetpp from SPEC CPU2017, shifting focus toward core throughput, and may complement rather than perfectly replace its predecessor.

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