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Thu, 8 Aug 2024 07:17:20 +0000 (GMT) Received: from epsmgms1p1new.samsung.com (unknown [182.195.42.41]) by epsmtrp1.samsung.com (KnoxPortal) with ESMTP id 20240808071720epsmtrp1dcfa43b2337bb47b9bcbddd865450478~pr6F9P9Gt1560815608epsmtrp1g; Thu, 8 Aug 2024 07:17:20 +0000 (GMT) X-AuditID: b6c32a50-c73ff70000004d97-10-66b47498f87f Received: from epsmtip2.samsung.com ( [182.195.34.31]) by epsmgms1p1new.samsung.com (Symantec Messaging Gateway) with SMTP id 30.E5.08964.00174B66; Thu, 8 Aug 2024 16:17:20 +0900 (KST) Received: from testpc11818.samsungds.net (unknown [109.105.118.18]) by epsmtip2.samsung.com (KnoxPortal) with ESMTPA id 20240808071719epsmtip2855c50da3224d3c4be37744b01a6d3e1~pr6EtEsbO1505915059epsmtip2f; Thu, 8 Aug 2024 07:17:19 +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 v7 RESENT] io_uring: releasing CPU resources when polling Date: Thu, 8 Aug 2024 15:17:12 +0800 Message-Id: <20240808071712.2429842-1-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+NgFvrDKsWRmVeSWpSXmKPExsWy7bCmhu6Mki1pBqdec1nMWbWN0WL13X42 i3et51gsfnXfZbS4vGsOm8XZCR9YLbounGJzYPfYOesuu8fls6UefVtWMXp83iQXwBKVbZOR mpiSWqSQmpecn5KZl26r5B0c7xxvamZgqGtoaWGupJCXmJtqq+TiE6DrlpkDdICSQlliTilQ KCCxuFhJ386mKL+0JFUhI7+4xFYptSAlp8CkQK84Mbe4NC9dLy+1xMrQwMDIFKgwITtj/9FX TAWLnSqWfb/E0sC4w7SLkZNDQsBEYlbzd8YuRi4OIYE9jBKfFzQxQzifGCV+XpzBCuF8Y5Q4 MGkKM0zL4yn/2EFsIYG9jBKb10RBFP0AslcsBytiE1CS2L/lAyOILSKgLfH68VSWLkYODmaB KIkXa7lBwsICnhJ/1x8FK2ERUJWY0LaeFaSEV8Ba4thmZ4hV8hI3u/aDTeQVEJQ4OfMJC4jN DBRv3job7FAJgVPsEs13LrBANLhI3OifyAhhC0u8Or6FHcKWknjZ3wZl50tM/r4eqqZGYt3m d1C91hL/ruyBOlNTYv0ufYiwrMTUU+uYIPbySfT+fsIEEeeV2DEPxlaSWHJkBdRICYnfExax QtgeEnd2LGaDBFWsxKvmXpYJjPKzkLwzC8k7sxA2L2BkXsUolVpQnJuemmxaYKibl1oOj9fk /NxNjOBkqBWwg3H1hr96hxiZOBgPMUpwMCuJ8DaHb0oT4k1JrKxKLcqPLyrNSS0+xGgKDOOJ zFKiyfnAdJxXEm9oYmlgYmZmZmJpbGaoJM77unVuipBAemJJanZqakFqEUwfEwenVAMTb8CM TX2uSy93ftq68p2m34/I3Lh5tufY2RZvut7dE+ycVFr4/ML3GRF3TCSs2/h+nfYREttx6wfT Q94jTuLLVt4v+Jzl8Jbl2ItXt3+o55v4dm7bPHFDy0l14Yvz6/i6+hcsCViafiF/ounLSF5R Ofnby15ZRewP0+kSbGhdwfAwr1JqX7RbVIjJvSUKUyrahFflGehYb00Tvsjh4b3qnMqaVVNU 3vwryDGQVopzaj4UcHjr5GhG/qkGk0oOspp9VfmUu0bo0ueF/If7iyv7r15fM8naLHX3n7WP 2ATWfj56kHXrhAmlBtsPs96UFIoPKbxcbRgq8etc+z2OFnGv5pt72bbt8Z16V2u7TAyLEktx RqKhFnNRcSIAt9vVaw8EAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrOLMWRmVeSWpSXmKPExsWy7bCSvC5D4ZY0g11TJSzmrNrGaLH6bj+b xbvWcywWv7rvMlpc3jWHzeLshA+sFl0XTrE5sHvsnHWX3ePy2VKPvi2rGD0+b5ILYInisklJ zcksSy3St0vgyth/9BVTwWKnimXfL7E0MO4w7WLk5JAQMJF4POUfexcjF4eQwG5GiTU33zND JCQkdjz6wwphC0us/Pccqugbo0T/ss0sIAk2ASWJ/Vs+MHYxcnCICOhKNN5VAAkzC8RIfNgz gR3EFhbwlPi7/igjiM0ioCoxoW09K0g5r4C1xLHNzhDj5SVudu0HW8srIChxcuYTFogx8hLN W2czT2Dkm4UkNQtJagEj0ypGydSC4tz03GLDAsO81HK94sTc4tK8dL3k/NxNjOCw1NLcwbh9 1Qe9Q4xMHIyHGCU4mJVEeJvDN6UJ8aYkVlalFuXHF5XmpBYfYpTmYFES5xV/0ZsiJJCeWJKa nZpakFoEk2Xi4JRqYMo/yRZi8tHhGMOrqguepsvZLjhltFq6t1foHvXseZ+69GmH7If0Yz09 +f/MzeIez17WsIhhRumSzZubTlt45551er1IZvvU2Um1T3oXz+fauKhb327zrTdTZm0tfsuT w7+nfuGhOHv2Y+mmIUf7d/+y2uITx734qq2tWWZxef2S0zHvIo1q1ousfLQnd6JM8J34Ob/W NvexXDr7v+aqXblqbaep/oOv8RX+og4LD+u2TLKYoCikk/t6od2T98lLHuxIYmp/abGd21fV KEZ3p/Bl4UXrJzyUTl606sK+uNcdz3bNFg7o8Tyf4lkduPeDy8kV/75FfTy0n6ProeaH42Wt t6Qflt8tOFLaYDxpU7ESS3FGoqEWc1FxIgCxdsNhugIAAA== X-CMS-MailID: 20240808071720epcas5p3f6f4f8abc6d4c02523dd4f64153a7cec 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: 20240808071720epcas5p3f6f4f8abc6d4c02523dd4f64153a7cec 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 of RESENT: - rebase code on for-6.12/io_uring 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 | 100 +++++++++++++++++++++++++++++---- 4 files changed, 99 insertions(+), 11 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..eb9791b50d36 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 +1114,83 @@ 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; + if (runtime < 0) + return 0; + + /* 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; @@ -1132,17 +1218,11 @@ 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