diff options
author | Bhanuprakash Bodireddy <bhanuprakash.bodireddy@intel.com> | 2016-10-14 15:37:07 +0100 |
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committer | Daniele Di Proietto <diproiettod@vmware.com> | 2016-10-17 18:32:40 -0700 |
commit | a17408e432b7faba04219f48f00f8067010b8aed (patch) | |
tree | aacff2aaf4f6aeca01f950d21739ffcc207fa5ab /lib | |
parent | 5c8f8763604972318a392ae83340e43bc41cf1f1 (diff) | |
download | openvswitch-a17408e432b7faba04219f48f00f8067010b8aed.tar.gz |
hash: Skip Invoking mhash_add__() with zero input.
mhash_add__() is expensive and should be only called with valid input.
zero-valued 'data' will not affect the 'hash' value and expensive hash
computation can be skipped when input is zero.
This patch will validate the input in mhash_add__ to save some cpu
cycles.
Signed-off-by: Bhanuprakash Bodireddy <bhanuprakash.bodireddy@intel.com>
Co-authored-by: Antonio Fischetti <antonio.fischetti@intel.com>
Signed-off-by: Antonio Fischetti <antonio.fischetti@intel.com>
Acked-by: Daniele Di Proietto <diproiettod@vmware.com>
Diffstat (limited to 'lib')
-rw-r--r-- | lib/hash.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/lib/hash.h b/lib/hash.h index 114a41999..f2dd51024 100644 --- a/lib/hash.h +++ b/lib/hash.h @@ -62,6 +62,11 @@ static inline uint32_t hash_string(const char *, uint32_t basis); static inline uint32_t mhash_add__(uint32_t hash, uint32_t data) { + /* zero-valued 'data' will not change the 'hash' value */ + if (!data) { + return hash; + } + data *= 0xcc9e2d51; data = hash_rot(data, 15); data *= 0x1b873593; |