2022-04-26 00:50 (UTC-0700), Tyler Retzlaff:
> Implement functions for getting/setting thread affinity.
> Threads can be pinned to specific cores by setting their
> affinity attribute.
>
> Windows error codes are translated to errno-style error codes.
> The possible return values are chosen so that we have as
> much semantic compatibility between platforms as possible.
>
> note: convert_cpuset_to_affinity has a limitation that all cpus of
> the set belong to the same processor group.
>
> Signed-off-by: Narcisa Vasile <navas...@microsoft.com>
> Signed-off-by: Tyler Retzlaff <roret...@linux.microsoft.com>
Acked-by: Dmitry Kozlyuk <dmitry.kozl...@gmail.com>
with two minor issues below.
> +static int
> +eal_query_group_affinity(void)
> +{
> + SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX *infos = NULL;
> + unsigned int *cpu_count = &cpu_map.cpu_count;
> + DWORD infos_size = 0;
> + int ret = 0;
> + USHORT group_count;
> + KAFFINITY affinity;
> + USHORT group_no;
> + unsigned int i;
> +
> + if (!GetLogicalProcessorInformationEx(RelationGroup, NULL,
> + &infos_size)) {
> + DWORD error = GetLastError();
> + if (error != ERROR_INSUFFICIENT_BUFFER) {
> + log_early("Cannot get group information size, error
> %lu\n", error);
This code is now called not only at initialization,
but also after the logging is set up,
in which case this line will not go into a redirected destination.
I think there should not be log_early() at all in EAL,
rte_log() could work from the very beginning.
We're not in the kernel, stderr is available at once.
So I would work around with a static flag maybe.
[...]
> +static int
> +convert_cpuset_to_affinity(const rte_cpuset_t *cpuset,
> + PGROUP_AFFINITY affinity)
> +{
> + int ret = 0;
> + PGROUP_AFFINITY cpu_affinity = NULL;
> + unsigned int cpu_idx;
> +
> + memset(affinity, 0, sizeof(GROUP_AFFINITY));
> + affinity->Group = (USHORT)-1;
> +
> + /* Check that all cpus of the set belong to the same processor group and
> + * accumulate thread affinity to be applied.
> + */
> + for (cpu_idx = 0; cpu_idx < CPU_SETSIZE; cpu_idx++) {
> + if (!CPU_ISSET(cpu_idx, cpuset))
> + continue;
> +
> + cpu_affinity = eal_get_cpu_affinity(cpu_idx);
> +
> + if (affinity->Group == (USHORT)-1) {
> + affinity->Group = cpu_affinity->Group;
> + } else if (affinity->Group != cpu_affinity->Group) {
> + ret = ENOTSUP;
Maybe worth a dedug log because the limitation is non-obvious.
