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| author |   Eric Dumazet <eric.dumazet@gmail.com> | 2009-10-07 00:37:59 +0000 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2009-10-07 22:00:22 -0700 |
| commit | f86dcc5aa8c7908f2c287e7a211228df599e3e71 (patch) | |
| tree | 1721c94d0254b337b0668b2e331771dfef4b142d /Documentation | |
| parent | IPv6: Fix 6RD typo (diff) | |
| download | linux-dev-f86dcc5aa8c7908f2c287e7a211228df599e3e71.tar.xz linux-dev-f86dcc5aa8c7908f2c287e7a211228df599e3e71.zip | |
udp: dynamically size hash tables at boot time
UDP_HTABLE_SIZE was initialy defined to 128, which is a bit small for
several setups.
4000 active UDP sockets -> 32 sockets per chain in average. An
incoming frame has to lookup all sockets to find best match, so long
chains hurt latency.
Instead of a fixed size hash table that cant be perfect for every
needs, let UDP stack choose its table size at boot time like tcp/ip
route, using alloc_large_system_hash() helper
Add an optional boot parameter, uhash_entries=x so that an admin can
force a size between 256 and 65536 if needed, like thash_entries and
rhash_entries.
dmesg logs two new lines :
[ 0.647039] UDP hash table entries: 512 (order: 0, 4096 bytes)
[ 0.647099] UDP Lite hash table entries: 512 (order: 0, 4096 bytes)
Maximal size on 64bit arches would be 65536 slots, ie 1 MBytes for non
debugging spinlocks.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/kernel-parameters.txt | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 6fa7292947e5..02df20be7764 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2589,6 +2589,9 @@ and is between 256 and 4096 characters. It is defined in the file uart6850= [HW,OSS] Format: <io>,<irq> + uhash_entries= [KNL,NET] + Set number of hash buckets for UDP/UDP-Lite connections + uhci-hcd.ignore_oc= [USB] Ignore overcurrent events (default N). Some badly-designed motherboards generate lots of |