ELJOnline: Real-Time and Linux, Part 2: The Preemptible Kernel

“With around Linux kernel release 2.2, the issue of kernel
preemptibility began to get quite a lot of attention. Paul
Barton-Davis and Benno Senoner, for example, wrote a letter (which
in addition was signed by many others) to Linus Torvalds, asking
that 2.4 please include significantly reduced preemption
delays.

“Their request was based on their desire to have Linux function
well with audio, music and MIDI. Senoner produced some benchmarking
software that demonstrated that the 2.2 kernel (and later the 2.4
kernel) had worst-case preemption latencies on the order of 100ms
(reference ). Latencies of this magnitude are unacceptable for
audio applications. Conventional wisdom seems to say that latencies
on the order of no more than a few milliseconds are
required…”

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