Patent · US Expired

Fast just-in-time (JIT) scheduler

US6139199A · kind A · utility

65Cited by
3References
36Claims
0Family size

Assignee

Inventor

Key dates

Filing dateJun 11, 1997
Grant dateOct 31, 2000
Priority date
Expiry dateJun 11, 2017

Classification

  • Technology area (CPC G)Physics
  • CPC primaryG06F8/445
  • WIPO fieldComputer technology
  • WIPO sectorElectrical engineering

Abstract

A just-in-time (JIT) compiler typically generates code from bytecodes that have a sequence of assembly instructions forming a "template". It has been discovered that a just-in-time (JIT) compiler generates a small number, approximately 2.3, assembly instructions per bytecode. It has also been discovered that, within a template, the assembly instructions are almost always dependent on the next assembly instruction. The absence of a dependence between instructions of different templates is exploited to increase the size of issue groups using scheduling. A fast method for scheduling program instructions is useful in just-in-time (JIT) compilers. Scheduling of instructions is generally useful for just-in-time (JIT) compilers that are targeted to in-order superscalar processors because the code generated by the JIT compilers is often sequential in nature. The disclosed fast scheduling method has a complexity, and therefore an execution time, that is proportional to the number of instructions in an instruction block (N complexity), a substantial improvement in comparison to the N.sup.2 complexity of conventional compiler schedulers. The described fast scheduler advantageously reorders in…

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.