On Thu Sep 5, 2024 at 11:08 AM EEST, Aaron Lu wrote:
> For optimized performance, firmware typically distributes EPC sections
> evenly across different NUMA nodes. However, there are scenarios where
> a node may have both CPUs and memory but no EPC section configured. For
> example, in an 8-socket system with a Sub-Numa-Cluster=2 setup, there
> are a total of 16 nodes. Given that the maximum number of supported EPC
> sections is 8, it is simply not feasible to assign one EPC section to
> each node. This configuration is not incorrect - SGX will still operate
> correctly; it is just not optimized from a NUMA standpoint.
>
> For this reason, log a message when a node with both CPUs and memory
> lacks an EPC section. This will provide users with a hint as to why they
> might be experiencing less-than-ideal performance when running SGX
> enclaves.
>
> Suggested-by: Dave Hansen <dave.hansen@xxxxxxxxx>
> Signed-off-by: Aaron Lu <aaron.lu@xxxxxxxxx>
> ---
> arch/x86/kernel/cpu/sgx/main.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
> index 694fcf7a5e3a..3a79105455f1 100644
> --- a/arch/x86/kernel/cpu/sgx/main.c
> +++ b/arch/x86/kernel/cpu/sgx/main.c
> @@ -848,6 +848,13 @@ static bool __init sgx_page_cache_init(void)
> return false;
> }
>
> + for_each_online_node(nid) {
> + if (!node_isset(nid, sgx_numa_mask) &&
> + node_state(nid, N_MEMORY) && node_state(nid, N_CPU))
> + pr_info("node%d has both CPUs and memory but doesn't have an EPC section\n",
> + nid);
Is this enough, or is there anything that would need to be done
automatically if this happens? With a tracepoint you could react to such
even but I'm totally fine with this.
> + }
> +
> return true;
> }
>
Reviewed-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
BR, Jarkko
