[lkml]   [2006]   [Jan]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [patch 3/4] net: Percpufy frequently used variables -- proto.sockets_allocated
Ravikiran G Thirumalai a écrit :
> Change the atomic_t sockets_allocated member of struct proto to a
> per-cpu counter.
> Signed-off-by: Pravin B. Shelar <>
> Signed-off-by: Ravikiran Thirumalai <>
> Signed-off-by: Shai Fultheim <>
Hi Ravikiran

If I correctly read this patch, I think there is a scalability problem.

On a big SMP machine, read_sockets_allocated() is going to be a real killer.

Say we have 128 Opterons CPUS in a box.

You'll need to bring 128 cache lines (plus 8*128 bytes to read the 128
pointers inside percpu structure)

I think a solution 'a la percpu_counter' is preferable, or even better a
dedicated per_cpu with a threshold management (see mm/swap.c , function
vm_acct_memory() to see how vm_committed_space is updated without too bad SMP

Thank you


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2006-01-27 09:57    [W:0.143 / U:0.248 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site