Re: [PATCH bpf-next] bpf: Speed up htab hashing for u32/u64 keys

["Alexei Starovoitov" <alexei.starovoitov@gmail.com>]

On Mon Sep 21, 2026 at 3:43 PM UTC, Alexei Starovoitov wrote:
> >  static inline u32 htab_map_hash(const void *key, u32 key_len, u32 hashrnd)
> >  {
> > -	if (likely(key_len % 4 == 0))
> > +	const u32 *k = key;
> > +	u32 b;
> > +
> > +	if (key_len == sizeof(u32))
> > +		b = 0;
> > +	else if (key_len == sizeof(u64))
> > +		b = k[1];
> > +	else if (likely(key_len % 4 == 0))
> >  		return jhash2(key, key_len / 4, hashrnd);

Nice improvement, but key_size is known at verification time.
Let's do a step further and specialize htab_map_gen_lookup
for small key sizes?