Re: [RFC PATCH bpf-next v2 0/6] bpf: add BPF_MAP_DUMP command to

From: Alexei Starovoitov
Date: Thu Jun 27 2019 - 18:14:40 EST


On Thu, Jun 27, 2019 at 01:24:11PM -0700, Brian Vazquez wrote:
> This introduces a new command to retrieve a variable number of entries
> from a bpf map.
>
> This new command can be executed from the existing BPF syscall as
> follows:
>
> err = bpf(BPF_MAP_DUMP, union bpf_attr *attr, u32 size)
> using attr->dump.map_fd, attr->dump.prev_key, attr->dump.buf,
> attr->dump.buf_len
> returns zero or negative error, and populates buf and buf_len on
> succees
>
> This implementation is wrapping the existing bpf methods:
> map_get_next_key and map_lookup_elem
> the results show that even with a 1-elem_size buffer, it runs ~40 faster
> than the current implementation, improvements of ~85% are reported when
> the buffer size is increased, although, after the buffer size is around
> 5% of the total number of entries there's no huge difference in
> increasing
> it.

was it with kpti and retpoline mitigations?