On 12/04/2022 16.09, Pavel Begunkov wrote:
io_get_cqe() is expensive because of a bunch of loads, masking, etc. However, most of the time we should have enough of entries in the CQ, so we can cache two pointers representing a range of contiguous CQE memory we can use. When the range is exhausted we'll go through a slower path to set up a new range. When there are no CQEs avaliable, pointers will naturally point to the same address. Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx> --- fs/io_uring.c | 46 +++++++++++++++++++++++++++++++++++----------- 1 file changed, 35 insertions(+), 11 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index b349a3c52354..f2269ffe09eb 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -416,6 +416,13 @@ struct io_ring_ctx { unsigned long check_cq_overflow;struct {+ /* + * We cache a range of free CQEs we can use, once exhausted it + * should go through a slower range setup, see __io_get_cqe() + */ + struct io_uring_cqe *cqe_cached; + struct io_uring_cqe *cqe_santinel;
I think this should s/santinel/sentinel. - Flow
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