diff options
| -rw-r--r-- | nest/rt-fib.c | 47 |
1 files changed, 44 insertions, 3 deletions
diff --git a/nest/rt-fib.c b/nest/rt-fib.c index 48091d43..a8800b65 100644 --- a/nest/rt-fib.c +++ b/nest/rt-fib.c @@ -58,11 +58,52 @@ #include "nest/route.h" #include "lib/string.h" +/* + * The FIB rehash values are maintaining FIB count between N/5 and 2N. What + * does it mean? + * + * +------------+--------+---------+-----------+----------+-----------+ + * | Table size | Memory | Min cnt | net + rte | Max cnt | net + rte | + * +------------+--------+---------+-----------+----------+-----------+ + * | 1k | 8k | 0 | 0 | 2k | 192 k | + * | 2k | 16k | 409 | 38.3k | 4k | 384 k | + * | 4k | 32k | 819 | 76.8k | 8k | 768 k | + * | 8k | 64k | 1.6k | 153.6k | 16k | 1.5M | + * | 16k | 128k | 3.2k | 307.1k | 32k | 3 M | + * | 32k | 256k | 6.4k | 614.3k | 64k | 6 M | + * | 64k | 512k | 12.8k | 1.2M | 128k | 12 M | + * | 128k | 1024k | 25.6k | 2.4M | 256k | 24 M | + * | 256k | 2M | 51.2k | 4.8M | 512k | 48 M | + * | 512k | 4M | 102.4k | 9.6M | 1M | 96 M | + * | 1M | 8M | 204.8k | 19.2M | 2M | 192 M | + * | 2M | 16M | 409.6k | 38.4M | 4M | 384 M | + * | 4M | 32M | 819.2k | 76.8M | 8M | 768 M | + * | 8M | 64M | 1.6M | 153.6M | infinity | infinity | + * +------------+--------+---------+-----------+----------+-----------+ + * + * Table size shows how many slots are in FIB table. + * Memory shows how much memory is eaten by FIB table. + * Min cnt minimal number of nets in table of given size + * Max cnt maximal number of nets in table of given size + * net + rte memory eaten by 1 net and one route in it for min cnt and max cnt + * + * Example: If we have 750,000 network entries in a table: + * * the table size may be 512k if we have never had more + * * the table size may be 1M or 2M if we at least happened to have more + * * 256k is too small, 8M is too big + * + * When growing, rehash is done on demand so we do it on every power of 2. + * When shrinking, rehash is done on delete which is done (in global tables) + * in a scheduled event. Rehashing down 2 steps. + * + */ + + #define HASH_DEF_ORDER 10 -#define HASH_HI_MARK *4 -#define HASH_HI_STEP 2 +#define HASH_HI_MARK * 2 +#define HASH_HI_STEP 1 #define HASH_HI_MAX 24 -#define HASH_LO_MARK /5 +#define HASH_LO_MARK / 5 #define HASH_LO_STEP 2 #define HASH_LO_MIN 10 |