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Mon, 12 Aug 2024 01:59:50 +0000 (GMT) Received: from epsmgms1p2new.samsung.com (unknown [182.195.42.42]) by epsmtrp2.samsung.com (KnoxPortal) with ESMTP id 20240812015950epsmtrp2a12add75393e5da230979bf0b6388e2e~q2KBbxnIM3032030320epsmtrp2r; Mon, 12 Aug 2024 01:59:50 +0000 (GMT) X-AuditID: b6c32a4b-613ff700000025aa-46-66b96d69e738 Received: from epsmtip2.samsung.com ( [182.195.34.31]) by epsmgms1p2new.samsung.com (Symantec Messaging Gateway) with SMTP id ED.55.08456.69C69B66; Mon, 12 Aug 2024 10:59:50 +0900 (KST) Received: from testpc11818.samsungds.net (unknown [109.105.118.18]) by epsmtip2.samsung.com (KnoxPortal) with ESMTPA id 20240812015949epsmtip2c9ffe16f63dc77c1899c718056755414~q2KAUAOw00030000300epsmtip2b; Mon, 12 Aug 2024 01:59:49 +0000 (GMT) From: hexue To: axboe@kernel.dk, asml.silence@gmail.com Cc: io-uring@vger.kernel.org, linux-kernel@vger.kernel.org, hexue Subject: [PATCH v8] io_uring: releasing CPU resources when polling Date: Mon, 12 Aug 2024 09:59:43 +0800 Message-Id: <20240812015943.3942523-1-xue01.he@samsung.com> X-Mailer: git-send-email 2.40.1 Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrLKsWRmVeSWpSXmKPExsWy7bCmum5m7s40gzvrNCzmrNrGaLH6bj+b xbvWcywWv7rvMlpc3jWHzeLshA+sFl0XTrE5sHvsnHWX3ePy2VKPvi2rGD0+b5ILYInKtslI TUxJLVJIzUvOT8nMS7dV8g6Od443NTMw1DW0tDBXUshLzE21VXLxCdB1y8wBOkBJoSwxpxQo FJBYXKykb2dTlF9akqqQkV9cYquUWpCSU2BSoFecmFtcmpeul5daYmVoYGBkClSYkJ3x5P40 poJVLhVb1s9kbGCcaN7FyMkhIWAi0dJxibGLkYtDSGA3o8TXd4+ZIJxPjBKX37exQjjfGCX2 zHvBDNPyqv8nVMteRokXl+dAtfxglHh2eQ8LSBWbgJLE/i0fGEFsEQFtidePpwLFOTiYBaIk XqzlBgkLCzhJnDl6iQ3EZhFQlZi0/zo7iM0rYC1x9N1xJohl8hI3u/YzQ8QFJU7OfAI2nhko 3rx1NjPIXgmBY+wSD17fh2pwkfjz5AE7hC0s8er4FihbSuLzu71sEHa+xOTv6xkh7BqJdZvf sUDY1hL/ruyBulNTYv0ufYiwrMTUU+uYIPbySfT+fgK1ildixzwYW0liyZEVUCMlJH5PWMQK YXtIzD/6CCwuJBArceXiFpYJjPKzkLwzC8k7sxA2L2BkXsUomVpQnJueWmxaYJyXWg6P2OT8 3E2M4HSo5b2D8dGDD3qHGJk4GA8xSnAwK4nwNodvShPiTUmsrEotyo8vKs1JLT7EaAoM44nM UqLJ+cCEnFcSb2hiaWBiZmZmYmlsZqgkzvu6dW6KkEB6YklqdmpqQWoRTB8TB6dUA1Py2q8x LX7XJnkvvmRrsGTnJ9mqnUJmUzfxn6kUY3V8UbYjJ/XZz4jC4z+fXF3R+i6Lrys0Npzj48KL 1ucW2S5pOX1q7W27l353f2o9nXphneG0n0UPV1WlTZ7by62X6FkidX/H7e2rE2baskmtEX8Z 4rDgTmE8X+bhA3tcOINykxmTSmJLnti2lP4Qr4z9rHhy7aI3R1lepkRfMcgvdT/7V1G/YKs7 Z0btUsGfHxhPeU0SyFZa9easX/Tz5ZHN6w7u15j3Ni/Uy9Il9f4iA7P7PxPtf7yd6cB5RXkS w6pzgdvXBF6cpflMu/bmP8Y75012XniWUZLw/+lDjvjQooo5q4LX9v73cz0T9POb1J9zSizF GYmGWsxFxYkAklBYHxAEAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrBLMWRmVeSWpSXmKPExsWy7bCSvO60nJ1pBn92KFnMWbWN0WL13X42 i3et51gsfnXfZbS4vGsOm8XZCR9YLbounGJzYPfYOesuu8fls6UefVtWMXp83iQXwBLFZZOS mpNZllqkb5fAlfHk/jSmglUuFVvWz2RsYJxo3sXIySEhYCLxqv8nYxcjF4eQwG5GiYuPbrJA JCQkdjz6wwphC0us/PecHaLoG6PE/lWbmUESbAJKEvu3fADq5uAQEdCVaLyrABJmFoiR+LBn AjuILSzgJHHm6CU2EJtFQFVi0v7rYHFeAWuJo++OM0HMl5e42bWfGSIuKHFy5hMWiDnyEs1b ZzNPYOSbhSQ1C0lqASPTKkbJ1ILi3PTcYsMCo7zUcr3ixNzi0rx0veT83E2M4MDU0trBuGfV B71DjEwcjIcYJTiYlUR4m8M3pQnxpiRWVqUW5ccXleakFh9ilOZgURLn/fa6N0VIID2xJDU7 NbUgtQgmy8TBKdXAtO3InX/pcgua/z6LVQj6yF4mfnqdrdaq3rWeGiIX5PI6Cp+FzOASWny7 OnqXSLUgU/VF3x/FJcc6khcXWpm4Kcj73p1eHf6h76Hb6Xnn1zwVCDXbsyeu4JuV5YF3seZW KjtbFk/7ukzl8/zyuB/2Fw5x5n4Okd/9rm2eXUBK++at708oH4puuF2b1cIsf6b2ek3Z6vwX HOWxJT11Sk0NiUINX/bxeFi9KS77WD9v0roZ2xf8V8njYjC9/5vtQbzFcXZ7hkUZ5tJPzZ7l 5Gw4uKntBQuH2ZHrP7dslZy6/UyY1cZbH1VUzrytFwq0Vm4zYbCYePItx4bP70LqArZUJs+L 8Js1oV/sff/B01bTlFiKMxINtZiLihMBoQnxIbsCAAA= X-CMS-MailID: 20240812015950epcas5p26c0eb254964abfe8a7ff05de0ead05f8 X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-Sendblock-Type: REQ_APPROVE CMS-TYPE: 105P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20240812015950epcas5p26c0eb254964abfe8a7ff05de0ead05f8 References: This patch add a new hybrid poll at io_uring level, it also set a signal "IORING_SETUP_HY_POLL" to application, aim to provide a interface for users to enable use new hybrid polling flexibly. io_uring use polling mode could improve the IO performence, but it will spend 100% of CPU resources to do polling. A new hybrid poll is implemented on the io_uring layer. Once IO issued, it will not polling immediately, but block first and re-run before IO complete, then poll to reap IO. This poll function could be a suboptimal solution when running on a single thread, it offers the performance lower than regular polling but higher than IRQ, and CPU utilization is also lower than polling. Test Result fio-3.35, 16 poll queues, 1 thread ------------------------------------------------------------------------- Performance ------------------------------------------------------------------------- write read randwrite randread regular poll BW=3939MiB/s BW=6613MiB/s IOPS=190K IOPS=470K IRQ BW=3927MiB/s BW=6612MiB/s IOPS=181K IOPS=203K hybrid poll BW=3937MiB/s BW=6623MiB/s IOPS=190K IOPS=358K(suboptimal) ------------------------------------------------------------------------- CPU Utilization ------------------------------------------------------ write read randwrite randread regular poll 100% 100% 100% 100% IRQ 50% 53% 100% 100% hybrid poll 70% 37% 70% 85% ------------------------------------------------------ -- changes since v7: - rebase code on for-6.12/io_uring - remove unused varibales changes since v6: - Modified IO path, distinct iopoll and uring_cmd_iopoll - update test results changes since v5: - Remove cstime recorder - Use minimize sleep time in different drivers - Use the half of whole runtime to do schedule - Consider as a suboptimal solution between regular poll and IRQ changes since v4: - Rewrote the commit - Update the test results - Reorganized the code basd on 6.11 changes since v3: - Simplified the commit - Add some comments on code changes since v2: - Modified some formatting errors - Move judgement to poll path changes since v1: - Extend hybrid poll to async polled io Signed-off-by: hexue --- include/linux/io_uring_types.h | 6 +++ include/uapi/linux/io_uring.h | 1 + io_uring/io_uring.c | 3 +- io_uring/rw.c | 99 ++++++++++++++++++++++++++++++---- 4 files changed, 97 insertions(+), 12 deletions(-) diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h index 3315005df117..35ac4a8bf6ab 100644 --- a/include/linux/io_uring_types.h +++ b/include/linux/io_uring_types.h @@ -422,6 +422,8 @@ struct io_ring_ctx { unsigned short n_sqe_pages; struct page **ring_pages; struct page **sqe_pages; + /* for io_uring hybrid poll*/ + u64 available_time; }; struct io_tw_state { @@ -657,6 +659,10 @@ struct io_kiocb { u64 extra1; u64 extra2; } big_cqe; + /* for io_uring hybrid iopoll */ + bool poll_state; + u64 iopoll_start; + u64 iopoll_end; }; struct io_overflow_cqe { diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 2aaf7ee256ac..42ae868651b0 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -199,6 +199,7 @@ enum io_uring_sqe_flags_bit { * Removes indirection through the SQ index array. */ #define IORING_SETUP_NO_SQARRAY (1U << 16) +#define IORING_SETUP_HY_POLL (1U << 17) enum io_uring_op { IORING_OP_NOP, diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 3942db160f18..bb3dfd749572 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -301,6 +301,7 @@ static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) goto err; ctx->flags = p->flags; + ctx->available_time = LLONG_MAX; atomic_set(&ctx->cq_wait_nr, IO_CQ_WAKE_INIT); init_waitqueue_head(&ctx->sqo_sq_wait); INIT_LIST_HEAD(&ctx->sqd_list); @@ -3603,7 +3604,7 @@ static long io_uring_setup(u32 entries, struct io_uring_params __user *params) IORING_SETUP_SQE128 | IORING_SETUP_CQE32 | IORING_SETUP_SINGLE_ISSUER | IORING_SETUP_DEFER_TASKRUN | IORING_SETUP_NO_MMAP | IORING_SETUP_REGISTERED_FD_ONLY | - IORING_SETUP_NO_SQARRAY)) + IORING_SETUP_NO_SQARRAY | IORING_SETUP_HY_POLL)) return -EINVAL; return io_uring_create(entries, &p, params); diff --git a/io_uring/rw.c b/io_uring/rw.c index c004d21e2f12..4d32b9b9900b 100644 --- a/io_uring/rw.c +++ b/io_uring/rw.c @@ -772,6 +772,13 @@ static bool need_complete_io(struct io_kiocb *req) S_ISBLK(file_inode(req->file)->i_mode); } +static void init_hybrid_poll(struct io_kiocb *req) +{ + /* make sure every req only block once*/ + req->poll_state = false; + req->iopoll_start = ktime_get_ns(); +} + static int io_rw_init_file(struct io_kiocb *req, fmode_t mode, int rw_type) { struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); @@ -809,6 +816,8 @@ static int io_rw_init_file(struct io_kiocb *req, fmode_t mode, int rw_type) kiocb->ki_flags |= IOCB_HIPRI; kiocb->ki_complete = io_complete_rw_iopoll; req->iopoll_completed = 0; + if (ctx->flags & IORING_SETUP_HY_POLL) + init_hybrid_poll(req); } else { if (kiocb->ki_flags & IOCB_HIPRI) return -EINVAL; @@ -1105,6 +1114,81 @@ void io_rw_fail(struct io_kiocb *req) io_req_set_res(req, res, req->cqe.flags); } +static int io_uring_classic_poll(struct io_kiocb *req, + struct io_comp_batch *iob, unsigned int poll_flags) +{ + int ret; + struct file *file = req->file; + + if (req->opcode == IORING_OP_URING_CMD) { + struct io_uring_cmd *ioucmd; + + ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd); + ret = file->f_op->uring_cmd_iopoll(ioucmd, iob, + poll_flags); + } else { + struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); + + ret = file->f_op->iopoll(&rw->kiocb, iob, poll_flags); + } + return ret; +} + +static u64 io_delay(struct io_ring_ctx *ctx, struct io_kiocb *req) +{ + struct hrtimer_sleeper timer; + enum hrtimer_mode mode; + ktime_t kt; + u64 sleep_time; + + if (req->poll_state) + return 0; + + if (ctx->available_time == LLONG_MAX) + return 0; + + /* Using half running time to do schedul */ + sleep_time = ctx->available_time / 2; + + kt = ktime_set(0, sleep_time); + req->poll_state = true; + + mode = HRTIMER_MODE_REL; + hrtimer_init_sleeper_on_stack(&timer, CLOCK_MONOTONIC, mode); + hrtimer_set_expires(&timer.timer, kt); + set_current_state(TASK_INTERRUPTIBLE); + hrtimer_sleeper_start_expires(&timer, mode); + + if (timer.task) + io_schedule(); + + hrtimer_cancel(&timer.timer); + __set_current_state(TASK_RUNNING); + destroy_hrtimer_on_stack(&timer.timer); + + return sleep_time; +} + +static int io_uring_hybrid_poll(struct io_kiocb *req, + struct io_comp_batch *iob, unsigned int poll_flags) +{ + struct io_ring_ctx *ctx = req->ctx; + int ret; + u64 runtime, sleep_time; + + sleep_time = io_delay(ctx, req); + ret = io_uring_classic_poll(req, iob, poll_flags); + req->iopoll_end = ktime_get_ns(); + runtime = req->iopoll_end - req->iopoll_start - sleep_time; + + /* use minimize sleep time if there are different speed + * drivers, it could get more completions from fast one + */ + if (ctx->available_time > runtime) + ctx->available_time = runtime; + return ret; +} + int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin) { struct io_wq_work_node *pos, *start, *prev; @@ -1121,7 +1205,6 @@ int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin) wq_list_for_each(pos, start, &ctx->iopoll_list) { struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list); - struct file *file = req->file; int ret; /* @@ -1132,17 +1215,11 @@ int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin) if (READ_ONCE(req->iopoll_completed)) break; - if (req->opcode == IORING_OP_URING_CMD) { - struct io_uring_cmd *ioucmd; - - ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd); - ret = file->f_op->uring_cmd_iopoll(ioucmd, &iob, - poll_flags); - } else { - struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); + if (ctx->flags & IORING_SETUP_HY_POLL) + ret = io_uring_hybrid_poll(req, &iob, poll_flags); + else + ret = io_uring_classic_poll(req, &iob, poll_flags); - ret = file->f_op->iopoll(&rw->kiocb, &iob, poll_flags); - } if (unlikely(ret < 0)) return ret; else if (ret) -- 2.40.1