A new hybrid poll is implemented on the io_uring layer. Once an IO is issued, it will not poll immediately, but rather block first and re-run before IO complete, then poll to reap IO. While this poll method could be a suboptimal solution when running on a single thread, it offers performance lower than regular polling but higher than IRQ, and CPU utilization is also lower than polling. To use hybrid polling, the ring must be setup with both the IORING_SETUP_IOPOLL and IORING_SETUP_HYBRID)IOPOLL flags set. Hybrid polling has the same restrictions as IOPOLL, in that commands must explicitly support it.
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| @@ -200,6 +200,9 @@ enum io_uring_sqe_flags_bit { · 199 unmodified lines | ||
| 200 | 200 | */ |
| 201 | 201 | #define IORING_SETUP_NO_SQARRAY (1U << 16) |
| 202 | 202 | |
| 203 | +/* Use hybrid poll in iopoll process */ | |
| 204 | +#define IORING_SETUP_HYBRID_IOPOLL (1U << 17) | |
| 205 | + | |
| 203 | 206 | enum io_uring_op { |
| 204 | 207 | IORING_OP_NOP, |
| 205 | 208 | IORING_OP_READV, |