[dpdk-dev] [PATCH] doc: add known issue of rte abort on FreeBSD
Burakov, Anatoly
anatoly.burakov at intel.com
Mon May 21 11:28:25 CEST 2018
On 18-May-18 3:23 PM, Reshma Pattan wrote:
> Added known issue of rte_abort taking a long time
> on FreeBSD due to recent memory subsystem rework.
>
> Signed-off-by: Reshma Pattan <reshma.pattan at intel.com>
> ---
> doc/guides/rel_notes/release_18_05.rst | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/doc/guides/rel_notes/release_18_05.rst b/doc/guides/rel_notes/release_18_05.rst
> index 3dcb62538..c01781956 100644
> --- a/doc/guides/rel_notes/release_18_05.rst
> +++ b/doc/guides/rel_notes/release_18_05.rst
> @@ -485,6 +485,21 @@ Known Issues
> dpdk-pdump example and any other applications using librte_pdump, cannot work
> with older version DPDK primary applications.
>
> +* **rte_abort takes a long time on FreeBSD due to memory subsytsem rework.**
> +
> + With the recent memory subsystem changes, DPDK processes now allocate a large
> + area of virtual memory address space. During rte_abort FreeBSD will dump the
> + contents of the whole reserved memory range, not just the used portion, to a
> + core dump file. Write this large core file can take a significant amount of
> + time, causing processes to appear hung on the system.
> +
> + The work around for the issue is to set the system resource limits for core
> + dumps before running any tests e.g."limit coredumpsize 0". This will
> + effectively disable core dumps on FreeBSD. If they are not to be completely
> + disabled, a suitable limit, e.g. 1G might be specified instead of 0. This
> + needs to be run per-shell session, or before every test run. This change
> + can also be made persistent by adding "kern.coredump=0" to /etc/sysctl.conf
> +
>
> Shared Library Versions
> -----------------------
>
The explanation is slightly wrong.
The slowdown was there before memory rework - FreeBSD apparently dumps
entire memory contents, including contigmem pages and anonymous pages.
It's just that previously, we didn't preallocate so much memory, so it
took ~5 seconds instead of minutes because it wasn't trying to dump 128
gigabytes of VA space.
Otherwise,
Acked-by: Anatoly Burakov <anatoly.burakov at intel.com>
--
Thanks,
Anatoly
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