9. EAL parameters

This document contains a list of all EAL parameters. These parameters can be used by any DPDK application running on Linux.

9.1. Common EAL parameters

The following EAL parameters are common to all platforms supported by DPDK.

9.1.5. Debugging options

  • --no-shconf

    No shared files created (implies no secondary process support).

  • --no-huge

    Use anonymous memory instead of hugepages (implies no secondary process support).

  • --log-level <type:val>

    Specify log level for a specific component. For example:

    --log-level lib.eal:debug

    Can be specified multiple times.

  • --trace=<regex-match>

    Enable trace based on regular expression trace name. By default, the trace is disabled. User must specify this option to enable trace. For example:

    Global trace configuration for EAL only:


    Global trace configuration for ALL the components:


    Can be specified multiple times up to 32 times.

  • --trace-dir=<directory path>

    Specify trace directory for trace output. For example:

    Configuring /tmp/ as a trace output directory:


    By default, trace output will created at home directory and parameter must be specified once only.

  • --trace-bufsz=<val>

    Specify maximum size of allocated memory for trace output for each thread. Valid unit can be either B or K or M for Bytes, KBytes and MBytes respectively. For example:

    Configuring 2MB as a maximum size for trace output file:


    By default, size of trace output file is 1MB and parameter must be specified once only.

  • --trace-mode=<o[verwrite] | d[iscard] >

    Specify the mode of update of trace output file. Either update on a file can be wrapped or discarded when file size reaches its maximum limit. For example:

    To discard update on trace output file:

    --trace-mode=d or --trace-mode=discard

    Default mode is overwrite and parameter must be specified once only.

9.1.6. Other options

  • -h, --help

    Display help message listing all EAL parameters.

  • -v

    Display the version information on startup.

  • --mbuf-pool-ops-name:

    Pool ops name for mbuf to use.

  • --telemetry:

Enable telemetry (enabled by default).
  • --no-telemetry:
Disable telemetry.
  • --force-max-simd-bitwidth=<val>:

Specify the maximum SIMD bitwidth size to handle. This limits which vector paths, if any, are taken, as any paths taken must use a bitwidth below the max bitwidth limit. For example, to allow all SIMD bitwidths up to and including AVX-512:


The following example shows limiting the bitwidth to 64-bits to disable all vector code:


To disable use of max SIMD bitwidth limit:


9.2. Linux-specific EAL parameters

In addition to common EAL parameters, there are also Linux-specific EAL parameters.

9.2.1. Device-related options

  • --create-uio-dev

    Create /dev/uioX files for devices bound to igb_uio kernel driver (usually done by the igb_uio driver itself).

  • --vmware-tsc-map

    Use VMware TSC map instead of native RDTSC.

  • --no-hpet

    Do not use the HPET timer.

  • --vfio-intr <legacy|msi|msix>

    Use specified interrupt mode for devices bound to VFIO kernel driver.

  • --vfio-vf-token <uuid>

    Use specified VF token for devices bound to VFIO kernel driver.

9.2.2. Multiprocessing-related options

  • --file-prefix <prefix name>

    Use a different shared data file prefix for a DPDK process. This option allows running multiple independent DPDK primary/secondary processes under different prefixes.

9.2.3. Memory-related options

  • --legacy-mem

    Use legacy DPDK memory allocation mode.

  • --socket-mem <amounts of memory per socket>

    Preallocate specified amounts of memory per socket. The parameter is a comma-separated list of values. For example:

    --socket-mem 1024,2048

    This will allocate 1 gigabyte of memory on socket 0, and 2048 megabytes of memory on socket 1.

  • --socket-limit <amounts of memory per socket>

    Place a per-socket upper limit on memory use (non-legacy memory mode only). 0 will disable the limit for a particular socket.

  • --single-file-segments

    Create fewer files in hugetlbfs (non-legacy mode only).

  • --huge-dir <path to hugetlbfs directory>

    Use specified hugetlbfs directory instead of autodetected ones. This can be a sub-directory within a hugetlbfs mountpoint.

  • --huge-unlink[=existing|always|never]

    No --huge-unlink option or --huge-unlink=existing is the default: existing hugepage files are removed and re-created to ensure the kernel clears the memory and prevents any data leaks.

    With --huge-unlink (no value) or --huge-unlink=always, hugepage files are also removed before mapping them, so that the application leaves no files in hugetlbfs. This mode implies no multi-process support.

    When --huge-unlink=never is specified, existing hugepage files are never removed, but are remapped instead, allowing hugepage reuse. This makes restart faster by saving time to clear memory at initialization, but it may slow down zeroed allocations later. Reused hugepages can contain data from previous processes that used them, which may be a security concern. Hugepage files created in this mode are also not removed when all the hugepages mapped from them are freed, which allows to reuse these files after a restart.

  • --match-allocations

    Free hugepages back to system exactly as they were originally allocated.

9.2.4. Other options

  • --syslog <syslog facility>

    Set syslog facility. Valid syslog facilities are: