borg-benchmark-cpu(1)

Name
borg-benchmark-cpu - Benchmark CPU-bound operations.

SYNOPSIS

borg [common options] benchmark cpu [options]

DESCRIPTION

This command benchmarks miscellaneous CPU-bound Borg operations.

It creates input data in memory, runs the operation and then displays throughput. To reduce outside influence on the timings, please make sure to run this with:

•   an otherwise as idle as possible machine

•   enough free memory so there will be no slow down due to paging activity

    By default all benchmarks run. Give one or more of --chunking, --hashing, --encrypting, --compressing, --msgpacking to run only those.

    Some algorithms use multiple threads only above a size threshold, so the hashes and the compressors are measured at more than one buffer size: the hashes at 64MiB (roughly pack-sized) and 2MiB (a typical borg chunk), both above blake3's threshold, the compressors at 2MiB and 128kiB, which is below zstd's. Within a section every row processes the same total number of bytes - 1 GiB, or 10 MiB for the compressors (the complete given data when using --data) - so the throughput column is comparable between rows.

    By default, the compressors work on synthetic text-like data that compresses about 4x at zstd,3. Random data would be the worst possible input: no codec can compress it, so all of them would take their incompressible fast path and the levels would barely differ.

    Synthetic data can still behave differently from your real data, so the compression benchmarks can instead run on data you provide with --data PATH: PATH is a file or a directory (all files below it are read and concatenated, up to 1 GiB). The complete data is compressed: it is cut into consecutive buffers of the measured sizes (a partial buffer at the end is skipped), so ratios and throughput reflect all of it, and the runtime scales with its size. Public benchmark corpora, e.g. the Silesia corpus or the Canterbury corpus, make good reproducible inputs that resemble real-world data (download and unpack them first, then point --data at the result).

    The compression rows also show the achieved compression ratio (uncompressed size / compressed size, higher is better).

OPTIONS

See borg-common(1) for common options of Borg commands.

  options

--json
    format output as JSON

--chunking
    benchmark the chunkers

--hashing
    benchmark the hashes / MACs

--encrypting
    benchmark the encryption modes

--compressing
    benchmark the compressors

--data PATH
    benchmark the compressors with the data from this file or directory (default: synthetic data)

--msgpacking
    benchmark msgpack item packing

SEE ALSO

borg-common(1)

Author
The Borg Collective