Messages in this thread |  | | Date | Sat, 13 Oct 2001 16:07:12 +0100 (BST) | From | Hugh Dickins <> | Subject | Re: Really slow netstat and /proc/net/tcp in 2.4 |
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On Sat, 13 Oct 2001, Andi Kleen wrote: > > I attached a patch. It allows you to get some simple statistics from > /proc/net/sockstat (unfortunately costly too). It also adds a new kernel > boot argument tcpehashgoal=order. Order is the log2 of how many pages you > want to use for the hash table (so it needs 2^order * 4096 bytes on i386) > You can experiment with various sizes and check which one gives still > reasonable hash distribution under load.
Wouldn't something like "tcpehashbuckets" make a better boot tunable than "tcpehashorder"? Rounded up to next power of two before used.
I come at this from the PAGE_SIZE angle, rather than the TCP angle: "order" tunables seem confusing to me (being interested in configurable PAGE_SIZE). And they're confusing to code too: note that the existing calculation of goal from num_physpages gives you more hash buckets for larger PAGE_SIZE (comment says "methodology is similar to that of the buffer cache", but buffer cache gets it right - though for small memory, would do better to multiply mempages by sizeof _before_ shifting right).
Hugh
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