Detailed characterization of the frontend shift in SPEC CPU 2026

Establish a rigorous characterization of the apparent shift in SPEC CPU 2026 frontend stalls toward instruction-fetch latency, including instruction-cache and instruction-TLB misses, relative to SPEC CPU 2017.

Background

The paper observes qualitatively that several SPEC CPU 2026 benchmarks may exhibit a larger proportion of frontend stalls caused by fetch latency—particularly instruction-cache and instruction-TLB misses—rather than decode-bandwidth limitations. The authors do not provide the supporting frontend decomposition and explicitly defer a detailed characterization to future work, leaving the magnitude and generality of this apparent shift unresolved.

References

We report this as a preliminary, qualitative observation: a rigorous frontend decomposition was beyond the scope of this study, and we do not present the supporting breakdown here. We leave a detailed characterization of this frontend shift to future work.

— Performance Characterization of SPEC CPU 2026 on AMD EPYC 9755 Processor  (2609.01527 - Kashyap et al., 1 Sep 2026) in Section 3.1, subsection “SPECrate®2026 at 1-Copy”