On 6/28/24 14:44, Simon Horman wrote:
On Tue, Jun 18, 2024 at 04:11:56PM +0200, Marcin Szycik wrote:
Currently when creating switch recipes, switch ID is always added as the
first word in every recipe. There are only 5 words in a recipe, so one
word is always wasted. This is also true for the last recipe, which stores
result indexes (in case of chain recipes). Therefore the maximum usable
length of a chain recipe is 4 * 4 = 16 words. 4 words in a recipe, 4
recipes that can be chained (using a 5th one for result indexes).
Current max size chained recipe:
0: smmmm
1: smmmm
2: smmmm
3: smmmm
4: srrrr
Where:
s - switch ID
m - regular match (e.g. ipv4 src addr, udp dst port, etc.)
r - result index
Switch ID does not actually need to be present in every recipe, only in one
of them (in case of chained recipe). This frees up to 8 extra words:
3 from recipes in the middle (because first recipe still needs to have
switch ID), and 5 from one extra recipe (because now the last recipe also
does not have switch ID, so it can chain 1 more recipe).
Max size chained recipe after changes:
0: smmmm
1: Mmmmm
2: Mmmmm
3: Mmmmm
4: MMMMM
5: Rrrrr
Extra usable words available after this change are highlighted with capital
letters.
Changing how switch ID is added is not straightforward, because it's not a
regular lookup. Its FV index and mask can't be determined based on protocol
+ offset pair read from package and instead need to be added manually.
Additionally, change how result indexes are added. Currently they are
always inserted in a new recipe at the end. Example for 13 words, (with
above optimization, switch ID being one of the words):
0: smmmm
1: mmmmm
2: mmmxx
3: rrrxx
Where:
x - unused word
In this and some other cases, the result indexes can be moved just after
last matches because there are unused words, saving one recipe. Example
for 13 words after both optimizations:
0: smmmm
1: mmmmm
2: mmmrr
Note how one less result index is needed in this case, because the last
recipe does not need to "link" to itself.
There are cases when adding an additional recipe for result indexes cannot
be avoided. In that cases result indexes are all put in the last recipe.
Example for 14 words after both optimizations:
0: smmmm
1: mmmmm
2: mmmmx
3: rrrxx
With these two changes, recipes/rules are more space efficient, allowing
more to be created in total.
Co-developed-by: Michal Swiatkowski <[email protected]>
Signed-off-by: Michal Swiatkowski <[email protected]>
Reviewed-by: Przemek Kitszel <[email protected]>
Signed-off-by: Marcin Szycik <[email protected]>
I appreciate the detailed description above, it is very helpful.
After a number of readings of this patch - it is complex -
I was unable to find anything wrong. And I do like both the simplification
and better hw utilisation that this patch (set) brings.
So from that perspective:
Reviewed-by: Simon Horman <[email protected]>
I would say, however, that it might have been easier to review
if somehow this patch was broken up into smaller pieces.
I appreciate that, in a sense, that is what the other patches
of this series do. But nonetheless... it is complex.
...
all of the "bugs" that I have internally found for this patch were
addressed by commit msg or comment changes ;)
what about you reviewing also patch 7 from v3 of this series?
