io_policy.hpp

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#ifndef JOIN_CORE_IO_POLICY_HPP
#define JOIN_CORE_IO_POLICY_HPP
 
// C.
#include <liburing.h>
#include <cstdint>
 
namespace join
{
    struct IoDefaultPolicy
    {
        static constexpr uint32_t sqEntries = 1024;
        static constexpr uint32_t flags = 0;
    };
 
    struct IoHybridPolicy
    {
        static constexpr uint32_t sqEntries = 1024;
        static constexpr uint32_t flags = 0;
        static constexpr uint64_t spinNs = 10'000;
        static constexpr uint64_t yieldNs = 100'000;
        static constexpr uint64_t sleepNs = 0;
        static constexpr uint64_t tickNs = 100;
    };
 
    struct IoSqpollPolicy
    {
        static constexpr uint32_t sqEntries = 1024;
        static constexpr uint32_t flags = IORING_SETUP_SQPOLL;
        static constexpr uint32_t sqThreadIdle = 2000;
        static constexpr uint64_t spinNs = 10'000;
        static constexpr uint64_t yieldNs = 100'000;
        static constexpr uint64_t sleepNs = 0;
        static constexpr uint64_t tickNs = 100;
    };
 
    template <typename T>
    inline constexpr bool has_sqpoll_v = (T::flags & IORING_SETUP_SQPOLL) != 0;
 
    template <typename T>
    inline constexpr bool has_cq_entries_v = requires { T::cqEntries; };
 
    template <typename T>
    inline constexpr bool has_sq_thread_idle_v = requires { T::sqThreadIdle; };
 
    template <typename T>
    inline constexpr bool has_sq_thread_cpu_v = requires { T::sqThreadCpu; };
 
    template <typename T>
    inline constexpr bool has_spin_v = requires { T::spinNs; };
 
    template <typename T>
    inline constexpr bool is_default_v = !has_spin_v<T> && !has_sqpoll_v<T>;
 
    template <typename T>
    inline constexpr uint64_t spin_ns_v = 10'000;
 
    template <typename T>
        requires has_spin_v<T>
    inline constexpr uint64_t spin_ns_v<T> = T::spinNs;
 
    template <typename T>
    inline constexpr bool has_yield_ns_v = requires { T::yieldNs; };
 
    template <typename T>
    inline constexpr uint64_t yield_ns_v = 100'000;
 
    template <typename T>
        requires has_yield_ns_v<T>
    inline constexpr uint64_t yield_ns_v<T> = T::yieldNs;
 
    template <typename T>
    inline constexpr bool has_sleep_ns_v = requires { T::sleepNs; };
 
    template <typename T>
    inline constexpr uint64_t sleep_ns_v = 0;
 
    template <typename T>
        requires has_sleep_ns_v<T>
    inline constexpr uint64_t sleep_ns_v<T> = T::sleepNs;
 
    template <typename T>
    inline constexpr bool has_tick_ns_v = requires { T::tickNs; };
 
    template <typename T>
    inline constexpr uint64_t tick_ns_v = 1'000;
 
    template <typename T>
        requires has_tick_ns_v<T>
    inline constexpr uint64_t tick_ns_v<T> = T::tickNs;
}
 
#endif