On Mon, Apr 07, 2025 at 02:24:51PM +0100, Bruce Richardson wrote: > The "--lcores" EAL parameter has a very powerful syntax that can be used > to provide precise control over lcore mappings. The docs however, only > provided a minimal description of what it can do. Augment the docs by > providing some examples of use of the option, and what the resulting > core mappings would be. > > Signed-off-by: Bruce Richardson <bruce.richard...@intel.com> > --- > doc/guides/linux_gsg/eal_args.include.rst | 25 +++++++++++++++++++++++ > 1 file changed, 25 insertions(+) > > diff --git a/doc/guides/linux_gsg/eal_args.include.rst > b/doc/guides/linux_gsg/eal_args.include.rst > index 9cfbf7de84..081f09d353 100644 > --- a/doc/guides/linux_gsg/eal_args.include.rst > +++ b/doc/guides/linux_gsg/eal_args.include.rst > @@ -29,6 +29,31 @@ Lcore-related options > The grouping ``()`` can be omitted for single element group. > The ``@`` can be omitted if cpus and lcores have the same value. > > + Examples: > + > + ``--lcores=1-3``: Run threads on physical CPUs 1, 2 and 3, > + with each thread having the same lcore id as the physical CPU id. > + > + ``--lcores=1@(1,2)``: Run a single thread with lcore id 1, > + but with that thread bound to both physical CPUs 1 and 2, > + so it can run on either, as determined by the operating system. > + > + ``--lcores='1@31,2@32,3@33'``: Run threads having internal lcore ids of > 1, 2 and 3, > + but with the threads being bound to physical CPUs 31, 32 and 33. > + > + ``--lcores='(1-3)@(31-33)'``: Run three threads with lcore ids 1, 2 and > 3. > + Unlike the previous example above, > + each of these threads is not bound to one specific lcore, > + but rather, all three threads are instead bound to the three physical > cores 31, 32 and 33. > + > + ``--lcores=(1-3)@20``: Run three threads, with lcore ids 1, 2 and 3, > + where all three threads are bound to (can only run on) physical CPU 20. > + > +.. Note:: > + Binding multiple DPDK lcores can cause problems with poor performance or > deadlock when using
I seem to have missed some words here. :-( V2 will be done soon. However, I will wait before sending it in case there is other feedback. /Bruce > + DPDK rings or memory pools or spinlocks. > + Such a configuration should only be used with care. > + > .. Note:: > At a given instance only one core option ``--lcores``, ``-l`` or ``-c`` > can > be used. > -- > 2.45.2 >
