The Linux kernel preemption project

SourceForge project page

Robert Love is now maintaining the latest kernel patches, at http://tech9.net/rml/linux, and at his kernel.org space.

Please join the kpreempt-tech mailing list here.

(Old kernel patches are here.)

Real-time benchmark results

All benchmarks were run on a 750MHz Pentium III with 128MB RAM.

Benno Senoner's Audio latency benchmark
- Results for Linux 2.4.6.
- Results for Linux 2.4.6 with kernel preemption patch.
- Summary: The preemptible kernel reduces the latency jitter to within 200盜 of the optimal scheduling time very consistently. There are just a few isolated unacceptable latencies. These are due to the long-held spinlocks that are still present in Linux 2.4. Preemption cannot take place while a spinlock is held.
RTC jitter benchmark (coming soon)

Other benchmark results

All benchmarks run on a 750MHz Pentium III with 128MB RAM.

Dbench

5 consecutive runs of "dbench -16".

Results for Linux 2.4.6.

Throughput 25.7806 MB/sec (NB=32.2257 MB/sec  257.806 MBit/sec)
Throughput 31.4287 MB/sec (NB=39.2859 MB/sec  314.287 MBit/sec)
Throughput 29.3438 MB/sec (NB=36.6797 MB/sec  293.438 MBit/sec)
Throughput 30.6667 MB/sec (NB=38.3334 MB/sec  306.667 MBit/sec)
Throughput 31.341  MB/sec (NB=39.1762 MB/sec  313.41  MBit/sec)

Results for Linux 2.4.6 with kernel preemption patch.

Throughput 26.4388 MB/sec (NB=33.0485 MB/sec  264.388 MBit/sec)
Throughput 25.8045 MB/sec (NB=32.2556 MB/sec  258.045 MBit/sec)
Throughput 32.0664 MB/sec (NB=40.083  MB/sec  320.664 MBit/sec)
Throughput 33.564  MB/sec (NB=41.955  MB/sec  335.64  MBit/sec)
Throughput 38.6235 MB/sec (NB=48.2793 MB/sec  386.235 MBit/sec)

Nigel Gamble
nigel@nrg.org

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