Re: [dpdk-dev] ACL lookup doesn't work for some schemes

["Ananyev, Konstantin" <konstantin.ananyev@intel.com>]

Hi

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of ???
> Sent: Sunday, February 15, 2015 9:19 AM
> To: dev@dpdk.org
> Subject: [dpdk-dev] ACL lookup doesn't work for some schemes
> 
> Hi,    I noticed that ACL lookup doesn't work for some schemes.1. If the first field is not uint8_t, even all fields are wildcard, lookup
> doesn't find the matching rule. See acl_8last.c.2. I prepended a uint8_t field, keep other fields be wildcard, lookup returns the correct
> result. See acl_8last2.c3. Then I change last field from 8bitmask_WILDCARD to 8bitmask(1, 0x1) (matches odd numbers) or 8bitmask(0,
> 0x1) (match even numbers), lookup doesn't return the correct. See acl_8last3.c.  And I noticed the similar behavior for uint16_t
> ranges(date doesn't match 0-0x8000 nor 0x8001-0xffff).    Above behaviors are tricky. Does ACL do some undocumented assumptions
> or the table schema?    Regards,Zhichang Yu

Yes, right now, libtre_acl to work correctly first field has to be 1B long and all subsequent grouped into sets of 4 consecutive bytes.
I thought we have it documented into our PG, ACL section:
http://dpdk.org/doc/guides/prog_guide/packet_classif_access_ctrl.html
Though re-reading it again:
"For performance reasons, the inner loop of the search function is unrolled to process four input bytes at a time. This requires the input to be grouped into sets of 4 consecutive bytes. The loop processes the first input byte as part of the setup and then subsequent bytes must be in groups of 4 consecutive bytes."
It probably not very clear and need to be explained in more details.
Will update the doc.

Konstantin