Re: [PATCH][v2] xfrm: replace NR_CPU with nr_cpu_ids
Steffen Klassert wrote: > On Tue, Jun 19, 2018 at 09:53:49AM +0200, Florian Westphal wrote: > > Li RongQing wrote: > > > The default NR_CPUS can be very large, but actual possible nr_cpu_ids > > > usually is very small. For some x86 distribution, the NR_CPUS is 8192 > > > and nr_cpu_ids is 4, so replace NR_CPU to save some memory > > > > Steffen, > > > > I will soon submit a patch to remove the percpu cache; removal > > improved performance for at least one user (and by quite a sizeable > > amount). > > > > Would you consider such removal for ipsec or ipsec-next? > > I think this removel would better fit to ipsec-next. Agree, it slows things down further for me in my tests. Problem is that I get quite good re-use of pcpu cache due to unidirectional flows and only one tunnel. I suspect that even with tunnel the removal is a win in practice though, netperf is quite artifical, so I rather trust Kristians results (real world) than my own. > considered to apply it to ipsec-next. If you plan > to remove it, I'll wait for that. I'll submit once net-next opens.
Re: [PATCH][v2] xfrm: replace NR_CPU with nr_cpu_ids
On Tue, Jun 19, 2018 at 09:53:49AM +0200, Florian Westphal wrote: > Li RongQing wrote: > > The default NR_CPUS can be very large, but actual possible nr_cpu_ids > > usually is very small. For some x86 distribution, the NR_CPUS is 8192 > > and nr_cpu_ids is 4, so replace NR_CPU to save some memory > > Steffen, > > I will soon submit a patch to remove the percpu cache; removal > improved performance for at least one user (and by quite a sizeable > amount). > > Would you consider such removal for ipsec or ipsec-next? I think this removel would better fit to ipsec-next. > If -next, consider applying this patch for ipsec.git. > > Otherwise consider not applying this, as the code will go away soon. This patch more an optimization than a fix, so I considered to apply it to ipsec-next. If you plan to remove it, I'll wait for that.
Re: [PATCH][v2] xfrm: replace NR_CPU with nr_cpu_ids
Li RongQing wrote: > The default NR_CPUS can be very large, but actual possible nr_cpu_ids > usually is very small. For some x86 distribution, the NR_CPUS is 8192 > and nr_cpu_ids is 4, so replace NR_CPU to save some memory Steffen, I will soon submit a patch to remove the percpu cache; removal improved performance for at least one user (and by quite a sizeable amount). Would you consider such removal for ipsec or ipsec-next? If -next, consider applying this patch for ipsec.git. Otherwise consider not applying this, as the code will go away soon. Thanks, Florian
Re: [PATCH][v2] xfrm: replace NR_CPU with nr_cpu_ids
On 2018/6/19 15:11, Li RongQing wrote:
> The default NR_CPUS can be very large, but actual possible nr_cpu_ids
> usually is very small. For some x86 distribution, the NR_CPUS is 8192
> and nr_cpu_ids is 4, so replace NR_CPU to save some memory
>
> Signed-off-by: Li RongQing
> Signed-off-by: Wang Li
> ---
> net/xfrm/xfrm_policy.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
> index 40b54cc64243..f8188685c1e9 100644
> --- a/net/xfrm/xfrm_policy.c
> +++ b/net/xfrm/xfrm_policy.c
> @@ -2989,11 +2989,11 @@ void __init xfrm_init(void)
> {
> int i;
>
> - xfrm_pcpu_work = kmalloc_array(NR_CPUS, sizeof(*xfrm_pcpu_work),
> + xfrm_pcpu_work = kmalloc_array(nr_cpu_ids, sizeof(*xfrm_pcpu_work),
> GFP_KERNEL);
It seems that xfrm_pcpu_work is not used anymore, maybe it can be deleted to
save more memory.
> BUG_ON(!xfrm_pcpu_work);
>
> - for (i = 0; i < NR_CPUS; i++)
> + for (i = 0; i < nr_cpu_ids; i++)
> INIT_WORK(&xfrm_pcpu_work[i], xfrm_pcpu_work_fn);
>
> register_pernet_subsys(&xfrm_net_ops);
>
[PATCH][v2] xfrm: replace NR_CPU with nr_cpu_ids
The default NR_CPUS can be very large, but actual possible nr_cpu_ids
usually is very small. For some x86 distribution, the NR_CPUS is 8192
and nr_cpu_ids is 4, so replace NR_CPU to save some memory
Signed-off-by: Li RongQing
Signed-off-by: Wang Li
---
net/xfrm/xfrm_policy.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 40b54cc64243..f8188685c1e9 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -2989,11 +2989,11 @@ void __init xfrm_init(void)
{
int i;
- xfrm_pcpu_work = kmalloc_array(NR_CPUS, sizeof(*xfrm_pcpu_work),
+ xfrm_pcpu_work = kmalloc_array(nr_cpu_ids, sizeof(*xfrm_pcpu_work),
GFP_KERNEL);
BUG_ON(!xfrm_pcpu_work);
- for (i = 0; i < NR_CPUS; i++)
+ for (i = 0; i < nr_cpu_ids; i++)
INIT_WORK(&xfrm_pcpu_work[i], xfrm_pcpu_work_fn);
register_pernet_subsys(&xfrm_net_ops);
--
2.16.2
