diff options
author | Anton Blanchard <anton@samba.org> | 2009-04-27 05:42:24 -0700 |
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committer | David S. Miller <davem@davemloft.net> | 2009-04-27 05:42:24 -0700 |
commit | c9503e0fe052020e0294cd07d0ecd982eb7c9177 (patch) | |
tree | aa0425fc1f30ebdf8d7455cf59db5c3ea2c7dfd0 /include/linux | |
parent | 2296e5a0136f7ba64c99f3a48a55a687aa9abcc8 (diff) |
ipv4: Limit size of route cache hash table
Right now we have no upper limit on the size of the route cache hash table.
On a 128GB POWER6 box it ends up as 32MB:
IP route cache hash table entries: 4194304 (order: 9, 33554432 bytes)
It would be nice to cap this for memory consumption reasons, but a massive
hashtable also causes a significant spike when measuring OS jitter.
With a 32MB hashtable and 4 million entries, rt_worker_func is taking
5 ms to complete. On another system with more memory it's taking 14 ms.
Even though rt_worker_func does call cond_sched() to limit its impact,
in an HPC environment we want to keep all sources of OS jitter to a minimum.
With the patch applied we limit the number of entries to 512k which
can still be overriden by using the rt_entries boot option:
IP route cache hash table entries: 524288 (order: 6, 4194304 bytes)
With this patch rt_worker_func now takes 0.460 ms on the same system.
Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux')
0 files changed, 0 insertions, 0 deletions