[PATCH v2 2/3] ip_frag: improve reassembly lookup performance

[Stephen Hemminger]

On Tue, 23 May 2023 20:09:20 +0530
<pbhagavatula at marvell.com> wrote:

> From: Pavan Nikhilesh <pbhagavatula at marvell.com>
> 
> Improve reassembly lookup performance by using NEON intrinsics for
> key validation.
> 
> Signed-off-by: Pavan Nikhilesh <pbhagavatula at marvell.com>
> ---
>  lib/ip_frag/ip_frag_internal.c   | 224 +++++++++++++++++++++++++------
>  lib/ip_frag/ip_reassembly.h      |   6 +
>  lib/ip_frag/rte_ip_frag_common.c |  10 ++
>  3 files changed, 196 insertions(+), 44 deletions(-)


Using a function pointer for the lookup has some downsides.
On Intel an indirect call is slower especially with SPECTRE mitigations.

The bigger issue is that indirect call will break usage from primary/secondary
process with ASLR. If primary sets up table and secondary uses it the function
will be in different places.