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lib/flow: Optimize minimask_has_extra() and minimask_is_catchall()

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We only need to iterate over the bits masked by the 'b' in
minimask_has_extra(), since for zeroes in 'b' there can be no 'extra'
wildcards in 'a', as 'b' has already wildcarded all the bits.

minimask_is_catchall() can be simplified by the invariant that mask's
map never has 1-bits for all-zero values.

Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: Ethan Jackson <ethan@nicira.com>
This commit is contained in:
Jarno Rajahalme
2014-04-29 15:50:38 -07:00
parent cabd4c4385
commit d4570fd8ba
2 changed files with 17 additions and 26 deletions
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31
lib/flow.c
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@@ -1859,19 +1859,17 @@ minimask_equal(const struct minimask *a, const struct minimask *b)
return miniflow_equal(&a->masks, &b->masks);
}
/* Returns true if at least one bit is wildcarded in 'a_' but not in 'b_',
/* Returns true if at least one bit matched by 'b' is wildcarded by 'a',
* false otherwise. */
bool
minimask_has_extra(const struct minimask *a_, const struct minimask *b_)
minimask_has_extra(const struct minimask *a, const struct minimask *b)
{
const struct miniflow *a = &a_->masks;
const struct miniflow *b = &b_->masks;
const uint32_t *p = b->masks.values;
uint64_t map;
for (map = a->map | b->map; map; map = zero_rightmost_1bit(map)) {
int ofs = raw_ctz(map);
uint32_t a_u32 = miniflow_get(a, ofs);
uint32_t b_u32 = miniflow_get(b, ofs);
for (map = b->masks.map; map; map = zero_rightmost_1bit(map)) {
uint32_t a_u32 = minimask_get(a, raw_ctz(map));
uint32_t b_u32 = *p++;
if ((a_u32 & b_u32) != b_u32) {
return true;
@@ -1880,20 +1878,3 @@ minimask_has_extra(const struct minimask *a_, const struct minimask *b_)
return false;
}
/* Returns true if 'mask' matches every packet, false if 'mask' fixes any bits
* or fields. */
bool
minimask_is_catchall(const struct minimask *mask_)
{
const struct miniflow *mask = &mask_->masks;
const uint32_t *p = mask->values;
uint64_t map;
for (map = mask->map; map; map = zero_rightmost_1bit(map)) {
if (*p++) {
return false;
}
}
return true;
}