公开(公告)号：US20250021333A1

公开(公告)日：2025-01-16

申请号：US18352323

申请日：2023-07-14

Applicant: Apple Inc.

Inventor： Ilhyun Kim ,  Niket K. Choudhary ,  Muawya M. Al-Otoom ,  Pruthivi Vuyyuru ,  Ronald P. Hall

IPC: G06F9/30 ,  G06F9/38

Abstract: Disclosed techniques relate to trace caches. Trace cache circuitry may identify traces that satisfy one or more criteria. Generally, internal branches of a trace should satisfy a threshold bias level in a particular direction. To achieve this goal, the processor may initially assume that branches meet the threshold, track their usefulness in the trace context over time, and prevent inclusion of branches that fall below a usefulness threshold (which indicates that those branches are not sufficiently biased). Branches that do not meet the threshold may be added to a Bloom filter, for example. Usefulness may be tracked during trace training, when valid in a trace cache, or both.

公开(公告)号：US20240028339A1

公开(公告)日：2024-01-25

申请号：US17814729

申请日：2022-07-25

Applicant: Apple Inc.

Inventor： Niket K. Choudhary ,  Mary D. Brown ,  Ethan R. Schuchman ,  Ronald P. Hall ,  Ian D. Kountanis ,  Douglas C. Holman ,  Ilhyun Kim ,  Abhishek Kumar ,  Siavash Zangeneh Kamali

IPC: G06F9/38 ,  G06F12/0875

CPC classification number: G06F9/3802 ,  G06F12/0875 ,  G06F2212/452

Abstract: An apparatus includes an instruction cache circuit and an instruction fetch circuit. The instruction fetch circuit is configured to retrieve, from the instruction cache circuit, a fetch group that includes a plurality of instructions for execution by a processing circuit, and to make a determination that the fetch group includes a control transfer instruction that is predicted to be taken. A target address associated with the control transfer instruction is directed to an instruction within the fetch group. The instruction fetch circuit is further configured to, based on the determination, alter instructions within the fetch group in a manner that is based on a type of the control transfer instruction.

公开(公告)号：US20250021332A1

公开(公告)日：2025-01-16

申请号：US18352309

申请日：2023-07-14

Applicant: Apple Inc.

Inventor： Niket K. Choudhary ,  Muawya M. Al-Otoom ,  Pruthivi Vuyyuru ,  Andrew H. Lin ,  Ilhyun Kim ,  Douglas C. Holman ,  Samir Dutt ,  Ronald P. Hall

IPC: G06F9/30 ,  G06F9/38

Abstract: Disclosed techniques relate to trace cache circuitry configured to identify and cache traces that satisfy certain criteria. Prediction circuitry may track directions of executed control transfer instructions, including a first category of control transfer instructions that meet a first threshold bias level toward a given direction (which may be referred to as “stable”) and a second category of control transfer instructions that do not meet the first threshold bias level (which may be referred to as “unstable”). Trace cache circuitry may identify traces of instructions that satisfy a set of criteria, including: only control transfer instructions of the first category are allowed as internal control transfer instructions and a control transfer instruction in the second category is allowed only at an end of a given trace. Disclosed techniques may advantageously provide performance and power advantages of trace caching with reduced complexity, relative to certain traditional trace caches.