From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0197630B517; Tue, 28 Apr 2026 20:36:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777408564; cv=none; b=V40y2LBMFLSyEnXigTc7MHRkzKGJqgxvC6qJoJt3odElv+M6tgAGkDsW+Vppx/LS1tcu62gqntUXYmCYer0/lPDu/6pUoIj8F2isN0HFYQqahO2z820YY0BcQqUc9abJ4CSiCjKJW9nIghRYPf3Obzm1KpJm70sXLXDbl+vhRsM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777408564; c=relaxed/simple; bh=+Olw5ZJqQBrqzajunFeEcsNjT8HiQQGZLa6082KfmZA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZXPptnZpZcMWCE+GujBspeRXQkWUOBH2S4W+gwDzjdcaPp05bammQk7GYSNdMu6tcNe6n4F7WSyaiN11+R0YwTeaxM7OwT4WSlvn7wYzWCDtZ0tNBx/lZmgMncUZ2DLoKhMR3E4epXIRKCVyEEMg7LEWuMBXP2wcbdN1dob2KcI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=B5FqtiZ1; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="B5FqtiZ1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B8F8DC2BCB7; Tue, 28 Apr 2026 20:36:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777408563; bh=+Olw5ZJqQBrqzajunFeEcsNjT8HiQQGZLa6082KfmZA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=B5FqtiZ1DgDhxTtcz8bLaBNxIoiG+t2nhrWZdZ0YKhWMmbSN+VqvQGQgPtZR+KTz9 fL2qa0CwavJnDtQfVplX2gKwiJvJKsvQORPudS8VA/UoqqxIJ0FsaVl442jHg6vy2/ HgTtgZrCH2VrPAgfdcMJO3O2/SNbcARNpFl+3VMbjrCK3tQZwi7AVCsvZwzjTloMBz 3/vtG5wgmpa6kJvwJf/bLjtYbvI0PwowjkJFb7qHsEd0i7i7OVxGbS1UevFjHWspGH 72cVfaol6ED40yCHpI0Ec8AjkgLYs6Ber3uGl6dUHFHfbhdEIPzSCugTafh8nCro1t Y6D1sL4HQ7J/Q== From: Tejun Heo To: David Vernet , Andrea Righi , Changwoo Min Cc: sched-ext@lists.linux.dev, Emil Tsalapatis , linux-kernel@vger.kernel.org, Tejun Heo , Cheng-Yang Chou Subject: [PATCH 16/17] tools/sched_ext: scx_qmap: Port to cid-form struct_ops Date: Tue, 28 Apr 2026 10:35:44 -1000 Message-ID: <20260428203545.181052-17-tj@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260428203545.181052-1-tj@kernel.org> References: <20260428203545.181052-1-tj@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Flip qmap's struct_ops to bpf_sched_ext_ops_cid. The kernel now passes cids and cmasks to callbacks directly, so the per-callback cpu<->cid translations that the prior patch added drop out and cpu_ctxs[] is reindexed by cid. Cpu-form kfunc calls switch to their cid-form counterparts. The cpu-only kfuncs (idle/any pick, cpumask iteration) have no cid substitute. Their callers already moved to cmask scans against qa_idle_cids and taskc->cpus_allowed in the prior patch, so the kfunc calls drop here without behavior changes. set_cmask is wired up via cmask_copy_from_kernel() to copy the kernel-supplied cmask into the arena-resident taskc cmask. The cpuperf monitor iterates the cid-form perf kfuncs. Signed-off-by: Tejun Heo Reviewed-by: Cheng-Yang Chou --- tools/sched_ext/scx_qmap.bpf.c | 231 +++++++++++++++++---------------- tools/sched_ext/scx_qmap.c | 59 ++++++++- tools/sched_ext/scx_qmap.h | 2 +- 3 files changed, 177 insertions(+), 115 deletions(-) diff --git a/tools/sched_ext/scx_qmap.bpf.c b/tools/sched_ext/scx_qmap.bpf.c index 88ef3936937d..f55192c7c51a 100644 --- a/tools/sched_ext/scx_qmap.bpf.c +++ b/tools/sched_ext/scx_qmap.bpf.c @@ -52,6 +52,28 @@ const volatile bool always_enq_immed; const volatile u32 immed_stress_nth; const volatile u32 max_tasks; +/* + * Optional cid-override test harness. When cid_override_mode is non-zero, + * qmap_init() calls scx_bpf_cid_override() with the caller-supplied arrays + * to exercise the kfunc's acceptance and error paths. + * + * 0 = disabled + * 1 = valid reverse mapping + * 2 = invalid: duplicate cid assignment + * 3 = invalid: non-monotonic shard_start + */ +const volatile u32 cid_override_mode; +const volatile u32 cid_override_nr_cpus; +const volatile u32 cid_override_nr_shards; +/* + * Arrays live in bss (writable) because scx_bpf_cid_override()'s BPF + * verifier signature treats its len-paired pointer as read/write - rodata + * fails verification with "write into map forbidden". Userspace populates + * them before SCX_OPS_LOAD, same as rodata, and nothing writes them after. + */ +s32 cid_override_cpu_to_cid[SCX_QMAP_MAX_CPUS]; +s32 cid_override_shard_start[SCX_QMAP_MAX_CPUS]; + UEI_DEFINE(uei); /* @@ -179,25 +201,24 @@ static int qmap_spin_lock(struct bpf_res_spin_lock *lock) } /* - * Try prev_cpu's cid, then scan taskc->cpus_allowed AND qa_idle_cids - * round-robin from prev_cid + 1. Atomic claim retries on race; bounded - * by IDLE_PICK_RETRIES to keep the verifier's insn budget in check. + * Try prev_cid, then scan taskc->cpus_allowed AND qa_idle_cids round-robin + * from prev_cid + 1. Atomic claim retries on race; bounded by + * IDLE_PICK_RETRIES to keep the verifier's insn budget in check. */ #define IDLE_PICK_RETRIES 16 -static s32 pick_direct_dispatch_cpu(struct task_struct *p, s32 prev_cpu, +static s32 pick_direct_dispatch_cid(struct task_struct *p, s32 prev_cid, task_ctx_t *taskc) { u32 nr_cids = scx_bpf_nr_cids(); - s32 prev_cid, cid; + s32 cid; u32 i; if (!always_enq_immed && p->nr_cpus_allowed == 1) - return prev_cpu; + return prev_cid; - prev_cid = scx_bpf_cpu_to_cid(prev_cpu); if (cmask_test_and_clear(qa_idle_cids, prev_cid)) - return prev_cpu; + return prev_cid; cid = prev_cid; bpf_for(i, 0, IDLE_PICK_RETRIES) { @@ -207,7 +228,7 @@ static s32 pick_direct_dispatch_cpu(struct task_struct *p, s32 prev_cpu, if (cid >= nr_cids) return -1; if (cmask_test_and_clear(qa_idle_cids, cid)) - return scx_bpf_cid_to_cpu(cid); + return cid; } return -1; } @@ -308,25 +329,25 @@ static void qmap_fifo_remove(task_ctx_t *taskc) bpf_res_spin_unlock(lock); } -s32 BPF_STRUCT_OPS(qmap_select_cpu, struct task_struct *p, - s32 prev_cpu, u64 wake_flags) +s32 BPF_STRUCT_OPS(qmap_select_cid, struct task_struct *p, + s32 prev_cid, u64 wake_flags) { task_ctx_t *taskc; - s32 cpu; + s32 cid; if (!(taskc = lookup_task_ctx(p))) - return prev_cpu; + return prev_cid; if (p->scx.weight < 2 && !(p->flags & PF_KTHREAD)) - return prev_cpu; + return prev_cid; - cpu = pick_direct_dispatch_cpu(p, prev_cpu, taskc); + cid = pick_direct_dispatch_cid(p, prev_cid, taskc); - if (cpu >= 0) { + if (cid >= 0) { taskc->force_local = true; - return cpu; + return cid; } else { - return prev_cpu; + return prev_cid; } } @@ -350,12 +371,12 @@ void BPF_STRUCT_OPS(qmap_enqueue, struct task_struct *p, u64 enq_flags) static u32 user_cnt, kernel_cnt; task_ctx_t *taskc; int idx = weight_to_idx(p->scx.weight); - s32 cpu; + s32 cid; if (enq_flags & SCX_ENQ_REENQ) { __sync_fetch_and_add(&qa.nr_reenqueued, 1); - if (scx_bpf_task_cpu(p) == 0) - __sync_fetch_and_add(&qa.nr_reenqueued_cpu0, 1); + if (scx_bpf_task_cid(p) == 0) + __sync_fetch_and_add(&qa.nr_reenqueued_cid0, 1); } if (p->flags & PF_KTHREAD) { @@ -388,14 +409,14 @@ void BPF_STRUCT_OPS(qmap_enqueue, struct task_struct *p, u64 enq_flags) if (!(++immed_stress_cnt % immed_stress_nth)) { taskc->force_local = false; - scx_bpf_dsq_insert(p, SCX_DSQ_LOCAL_ON | scx_bpf_task_cpu(p), + scx_bpf_dsq_insert(p, SCX_DSQ_LOCAL_ON | scx_bpf_task_cid(p), slice_ns, enq_flags); return; } } /* - * If qmap_select_cpu() is telling us to or this is the last runnable + * If qmap_select_cid() is telling us to or this is the last runnable * task on the CPU, enqueue locally. */ if (taskc->force_local) { @@ -411,11 +432,11 @@ void BPF_STRUCT_OPS(qmap_enqueue, struct task_struct *p, u64 enq_flags) return; } - /* if select_cpu() wasn't called, try direct dispatch */ + /* if select_cid() wasn't called, try direct dispatch */ if (!__COMPAT_is_enq_cpu_selected(enq_flags) && - (cpu = pick_direct_dispatch_cpu(p, scx_bpf_task_cpu(p), taskc)) >= 0) { + (cid = pick_direct_dispatch_cid(p, scx_bpf_task_cid(p), taskc)) >= 0) { __sync_fetch_and_add(&qa.nr_ddsp_from_enq, 1); - scx_bpf_dsq_insert(p, SCX_DSQ_LOCAL_ON | cpu, slice_ns, enq_flags); + scx_bpf_dsq_insert(p, SCX_DSQ_LOCAL_ON | cid, slice_ns, enq_flags); return; } @@ -423,15 +444,16 @@ void BPF_STRUCT_OPS(qmap_enqueue, struct task_struct *p, u64 enq_flags) * If the task was re-enqueued due to the CPU being preempted by a * higher priority scheduling class, just re-enqueue the task directly * on the global DSQ. As we want another CPU to pick it up, find and - * kick an idle CPU. + * kick an idle cid. */ if (enq_flags & SCX_ENQ_REENQ) { - s32 cpu; + s32 cid; scx_bpf_dsq_insert(p, SHARED_DSQ, 0, enq_flags); - cpu = scx_bpf_pick_idle_cpu(p->cpus_ptr, 0); - if (cpu >= 0) - scx_bpf_kick_cpu(cpu, SCX_KICK_IDLE); + cid = cmask_next_and_set_wrap(&taskc->cpus_allowed, + qa_idle_cids, 0); + if (cid < scx_bpf_nr_cids()) + scx_bpf_kick_cid(cid, SCX_KICK_IDLE); return; } @@ -483,7 +505,8 @@ static void update_core_sched_head_seq(struct task_struct *p) static bool dispatch_highpri(bool from_timer) { struct task_struct *p; - s32 this_cpu = bpf_get_smp_processor_id(); + s32 this_cid = scx_bpf_this_cid(); + u32 nr_cids = scx_bpf_nr_cids(); /* scan SHARED_DSQ and move highpri tasks to HIGHPRI_DSQ */ bpf_for_each(scx_dsq, p, SHARED_DSQ, 0) { @@ -502,21 +525,29 @@ static bool dispatch_highpri(bool from_timer) } /* - * Scan HIGHPRI_DSQ and dispatch until a task that can run on this CPU - * is found. + * Scan HIGHPRI_DSQ and dispatch until a task that can run here is + * found. Prefer this_cid if the task allows it; otherwise RR-scan the + * task's cpus_allowed starting after this_cid. */ bpf_for_each(scx_dsq, p, HIGHPRI_DSQ, 0) { + task_ctx_t *taskc; bool dispatched = false; - s32 cpu; + s32 cid; - if (bpf_cpumask_test_cpu(this_cpu, p->cpus_ptr)) - cpu = this_cpu; + if (!(taskc = lookup_task_ctx(p))) + return false; + + if (cmask_test(&taskc->cpus_allowed, this_cid)) + cid = this_cid; else - cpu = scx_bpf_pick_any_cpu(p->cpus_ptr, 0); + cid = cmask_next_set_wrap(&taskc->cpus_allowed, + this_cid + 1); + if (cid >= nr_cids) + continue; - if (scx_bpf_dsq_move(BPF_FOR_EACH_ITER, p, SCX_DSQ_LOCAL_ON | cpu, + if (scx_bpf_dsq_move(BPF_FOR_EACH_ITER, p, SCX_DSQ_LOCAL_ON | cid, SCX_ENQ_PREEMPT)) { - if (cpu == this_cpu) { + if (cid == this_cid) { dispatched = true; __sync_fetch_and_add(&qa.nr_expedited_local, 1); } else { @@ -535,7 +566,7 @@ static bool dispatch_highpri(bool from_timer) return false; } -void BPF_STRUCT_OPS(qmap_dispatch, s32 cpu, struct task_struct *prev) +void BPF_STRUCT_OPS(qmap_dispatch, s32 cid, struct task_struct *prev) { struct task_struct *p; struct cpu_ctx __arena *cpuc; @@ -563,7 +594,7 @@ void BPF_STRUCT_OPS(qmap_dispatch, s32 cpu, struct task_struct *prev) } } - cpuc = &qa.cpu_ctxs[bpf_get_smp_processor_id()]; + cpuc = &qa.cpu_ctxs[scx_bpf_this_cid()]; for (i = 0; i < 5; i++) { /* Advance the dispatch cursor and pick the fifo. */ @@ -628,8 +659,8 @@ void BPF_STRUCT_OPS(qmap_dispatch, s32 cpu, struct task_struct *prev) * document this class of issue -- other schedulers * seeing similar warnings can use this as a reference. */ - if (!bpf_cpumask_test_cpu(cpu, p->cpus_ptr)) - scx_bpf_kick_cpu(scx_bpf_task_cpu(p), 0); + if (!cmask_test(&taskc->cpus_allowed, cid)) + scx_bpf_kick_cid(scx_bpf_task_cid(p), 0); batch--; cpuc->dsp_cnt--; @@ -668,7 +699,7 @@ void BPF_STRUCT_OPS(qmap_dispatch, s32 cpu, struct task_struct *prev) void BPF_STRUCT_OPS(qmap_tick, struct task_struct *p) { - struct cpu_ctx __arena *cpuc = &qa.cpu_ctxs[bpf_get_smp_processor_id()]; + struct cpu_ctx __arena *cpuc = &qa.cpu_ctxs[scx_bpf_this_cid()]; int idx; /* @@ -680,7 +711,7 @@ void BPF_STRUCT_OPS(qmap_tick, struct task_struct *p) idx = weight_to_idx(cpuc->avg_weight); cpuc->cpuperf_target = qidx_to_cpuperf_target[idx]; - scx_bpf_cpuperf_set(scx_bpf_task_cpu(p), cpuc->cpuperf_target); + scx_bpf_cidperf_set(scx_bpf_task_cid(p), cpuc->cpuperf_target); } /* @@ -828,9 +859,9 @@ void BPF_STRUCT_OPS(qmap_dump, struct scx_dump_ctx *dctx) } } -void BPF_STRUCT_OPS(qmap_dump_cpu, struct scx_dump_ctx *dctx, s32 cpu, bool idle) +void BPF_STRUCT_OPS(qmap_dump_cid, struct scx_dump_ctx *dctx, s32 cid, bool idle) { - struct cpu_ctx __arena *cpuc = &qa.cpu_ctxs[cpu]; + struct cpu_ctx __arena *cpuc = &qa.cpu_ctxs[cid]; if (suppress_dump || idle) return; @@ -881,46 +912,24 @@ void BPF_STRUCT_OPS(qmap_cgroup_set_bandwidth, struct cgroup *cgrp, cgrp->kn->id, period_us, quota_us, burst_us); } -void BPF_STRUCT_OPS(qmap_update_idle, s32 cpu, bool idle) +void BPF_STRUCT_OPS(qmap_update_idle, s32 cid, bool idle) { - s32 cid = scx_bpf_cpu_to_cid(cpu); - QMAP_TOUCH_ARENA(); - if (cid < 0) - return; if (idle) cmask_set(qa_idle_cids, cid); else cmask_clear(qa_idle_cids, cid); } -/* - * The cpumask received here is kernel-address memory; walk it bit by bit - * (bpf_cpumask_test_cpu handles the access), convert each set cpu to its - * cid, and populate the arena-resident taskc cmask. - */ -void BPF_STRUCT_OPS(qmap_set_cpumask, struct task_struct *p, - const struct cpumask *cpumask) +void BPF_STRUCT_OPS(qmap_set_cmask, struct task_struct *p, + const struct scx_cmask *cmask) { task_ctx_t *taskc; - u32 nr_cpu_ids = scx_bpf_nr_cpu_ids(); - s32 cpu; taskc = lookup_task_ctx(p); if (!taskc) return; - - cmask_zero(&taskc->cpus_allowed); - - bpf_for(cpu, 0, nr_cpu_ids) { - s32 cid; - - if (!bpf_cpumask_test_cpu(cpu, cpumask)) - continue; - cid = scx_bpf_cpu_to_cid(cpu); - if (cid >= 0) - __cmask_set(&taskc->cpus_allowed, cid); - } + cmask_copy_from_kernel(&taskc->cpus_allowed, cmask); } struct monitor_timer { @@ -935,59 +944,49 @@ struct { } monitor_timer SEC(".maps"); /* - * Print out the min, avg and max performance levels of CPUs every second to - * demonstrate the cpuperf interface. + * Aggregate cidperf across the first nr_online_cids cids. Post-hotplug + * the first-N-are-online invariant drifts, so some cap/cur values may + * be stale. For this demo monitor that's fine; the scheduler exits on + * the enable-time hotplug_seq mismatch and userspace restarts, which + * rebuilds the layout. */ static void monitor_cpuperf(void) { - u32 nr_cpu_ids; + u32 nr_online = scx_bpf_nr_online_cids(); u64 cap_sum = 0, cur_sum = 0, cur_min = SCX_CPUPERF_ONE, cur_max = 0; u64 target_sum = 0, target_min = SCX_CPUPERF_ONE, target_max = 0; - const struct cpumask *online; - int i, nr_online_cpus = 0; - - nr_cpu_ids = scx_bpf_nr_cpu_ids(); - online = scx_bpf_get_online_cpumask(); - - bpf_for(i, 0, nr_cpu_ids) { - struct cpu_ctx __arena *cpuc = &qa.cpu_ctxs[i]; - u32 cap, cur; + s32 cid; - if (!bpf_cpumask_test_cpu(i, online)) - continue; - nr_online_cpus++; + QMAP_TOUCH_ARENA(); - /* collect the capacity and current cpuperf */ - cap = scx_bpf_cpuperf_cap(i); - cur = scx_bpf_cpuperf_cur(i); + bpf_for(cid, 0, nr_online) { + struct cpu_ctx __arena *cpuc = &qa.cpu_ctxs[cid]; + u32 cap = scx_bpf_cidperf_cap(cid); + u32 cur = scx_bpf_cidperf_cur(cid); + u32 target; cur_min = cur < cur_min ? cur : cur_min; cur_max = cur > cur_max ? cur : cur_max; - /* - * $cur is relative to $cap. Scale it down accordingly so that - * it's in the same scale as other CPUs and $cur_sum/$cap_sum - * makes sense. - */ - cur_sum += cur * cap / SCX_CPUPERF_ONE; + cur_sum += (u64)cur * cap / SCX_CPUPERF_ONE; cap_sum += cap; - /* collect target */ - cur = cpuc->cpuperf_target; - target_sum += cur; - target_min = cur < target_min ? cur : target_min; - target_max = cur > target_max ? cur : target_max; + target = cpuc->cpuperf_target; + target_sum += target; + target_min = target < target_min ? target : target_min; + target_max = target > target_max ? target : target_max; } + if (!nr_online || !cap_sum) + return; + qa.cpuperf_min = cur_min; qa.cpuperf_avg = cur_sum * SCX_CPUPERF_ONE / cap_sum; qa.cpuperf_max = cur_max; qa.cpuperf_target_min = target_min; - qa.cpuperf_target_avg = target_sum / nr_online_cpus; + qa.cpuperf_target_avg = target_sum / nr_online; qa.cpuperf_target_max = target_max; - - scx_bpf_put_cpumask(online); } /* @@ -1083,6 +1082,18 @@ s32 BPF_STRUCT_OPS_SLEEPABLE(qmap_init) return -EINVAL; } + /* + * cid-override test hook. Must run before anything that reads the + * cid space (scx_bpf_nr_cids, cmask_init, etc.). On invalid input, + * the kfunc calls scx_error() which aborts the scheduler. + */ + if (cid_override_mode) { + scx_bpf_cid_override((const s32 *)cid_override_cpu_to_cid, + cid_override_nr_cpus * sizeof(s32), + (const s32 *)cid_override_shard_start, + cid_override_nr_shards * sizeof(s32)); + } + /* * Allocate the task_ctx slab in arena and thread the entire slab onto * the free list. max_tasks is set by userspace before load. Each entry @@ -1199,20 +1210,20 @@ void BPF_STRUCT_OPS(qmap_sub_detach, struct scx_sub_detach_args *args) } } -SCX_OPS_DEFINE(qmap_ops, +SCX_OPS_CID_DEFINE(qmap_ops, .flags = SCX_OPS_ENQ_EXITING | SCX_OPS_TID_TO_TASK, - .select_cpu = (void *)qmap_select_cpu, + .select_cid = (void *)qmap_select_cid, .enqueue = (void *)qmap_enqueue, .dequeue = (void *)qmap_dequeue, .dispatch = (void *)qmap_dispatch, .tick = (void *)qmap_tick, .core_sched_before = (void *)qmap_core_sched_before, - .set_cpumask = (void *)qmap_set_cpumask, + .set_cmask = (void *)qmap_set_cmask, .update_idle = (void *)qmap_update_idle, .init_task = (void *)qmap_init_task, .exit_task = (void *)qmap_exit_task, .dump = (void *)qmap_dump, - .dump_cpu = (void *)qmap_dump_cpu, + .dump_cid = (void *)qmap_dump_cid, .dump_task = (void *)qmap_dump_task, .cgroup_init = (void *)qmap_cgroup_init, .cgroup_set_weight = (void *)qmap_cgroup_set_weight, diff --git a/tools/sched_ext/scx_qmap.c b/tools/sched_ext/scx_qmap.c index 99408b1bb1ec..a533542e3ca5 100644 --- a/tools/sched_ext/scx_qmap.c +++ b/tools/sched_ext/scx_qmap.c @@ -43,6 +43,7 @@ const char help_fmt[] = " -p Switch only tasks on SCHED_EXT policy instead of all\n" " -I Turn on SCX_OPS_ALWAYS_ENQ_IMMED\n" " -F COUNT IMMED stress: force every COUNT'th enqueue to a busy local DSQ (use with -I)\n" +" -C MODE cid-override test (shuffle|bad-dup|bad-mono)\n" " -v Print libbpf debug messages\n" " -h Display this help and exit\n"; @@ -73,6 +74,14 @@ int main(int argc, char **argv) libbpf_set_print(libbpf_print_fn); signal(SIGINT, sigint_handler); signal(SIGTERM, sigint_handler); + + if (libbpf_num_possible_cpus() > SCX_QMAP_MAX_CPUS) { + fprintf(stderr, + "scx_qmap: %d possible CPUs exceeds compile-time cap %d; " + "rebuild with larger SCX_QMAP_MAX_CPUS\n", + libbpf_num_possible_cpus(), SCX_QMAP_MAX_CPUS); + return 1; + } restart: optind = 1; skel = SCX_OPS_OPEN(qmap_ops, scx_qmap); @@ -80,7 +89,7 @@ int main(int argc, char **argv) skel->rodata->slice_ns = __COMPAT_ENUM_OR_ZERO("scx_public_consts", "SCX_SLICE_DFL"); skel->rodata->max_tasks = 16384; - while ((opt = getopt(argc, argv, "s:e:t:T:l:b:N:PMHc:d:D:SpIF:vh")) != -1) { + while ((opt = getopt(argc, argv, "s:e:t:T:l:b:N:PMHc:d:D:SpIF:C:vh")) != -1) { switch (opt) { case 's': skel->rodata->slice_ns = strtoull(optarg, NULL, 0) * 1000; @@ -143,6 +152,48 @@ int main(int argc, char **argv) case 'F': skel->rodata->immed_stress_nth = strtoul(optarg, NULL, 0); break; + case 'C': { + u32 nr_cpus = libbpf_num_possible_cpus(); + u32 mode, i; + s32 shard_sz = 4; + + if (!strcmp(optarg, "shuffle")) + mode = 1; + else if (!strcmp(optarg, "bad-dup")) + mode = 2; + else if (!strcmp(optarg, "bad-mono")) + mode = 3; + else { + fprintf(stderr, "unknown cid-override mode '%s'\n", optarg); + return 1; + } + skel->rodata->cid_override_mode = mode; + skel->rodata->cid_override_nr_cpus = nr_cpus; + + /* shuffle: reversed cpu_to_cid, bad-dup: dup cid 0, bad-mono: identity */ + for (i = 0; i < nr_cpus; i++) { + if (mode == 1) + skel->bss->cid_override_cpu_to_cid[i] = nr_cpus - 1 - i; + else + skel->bss->cid_override_cpu_to_cid[i] = i; + } + if (mode == 2 && nr_cpus >= 2) + skel->bss->cid_override_cpu_to_cid[1] = 0; + + /* shards of shard_sz each */ + skel->rodata->cid_override_nr_shards = (nr_cpus + shard_sz - 1) / shard_sz; + for (i = 0; i < skel->rodata->cid_override_nr_shards; i++) + skel->bss->cid_override_shard_start[i] = i * shard_sz; + + if (mode == 3 && skel->rodata->cid_override_nr_shards >= 3) { + /* swap [1] and [2] so shard_start is not monotonically increasing */ + s32 tmp = skel->bss->cid_override_shard_start[1]; + skel->bss->cid_override_shard_start[1] = + skel->bss->cid_override_shard_start[2]; + skel->bss->cid_override_shard_start[2] = tmp; + } + break; + } case 'v': verbose = true; break; @@ -162,9 +213,9 @@ int main(int argc, char **argv) long nr_enqueued = qa->nr_enqueued; long nr_dispatched = qa->nr_dispatched; - printf("stats : enq=%lu dsp=%lu delta=%ld reenq/cpu0=%llu/%llu deq=%llu core=%llu enq_ddsp=%llu\n", + printf("stats : enq=%lu dsp=%lu delta=%ld reenq/cid0=%llu/%llu deq=%llu core=%llu enq_ddsp=%llu\n", nr_enqueued, nr_dispatched, nr_enqueued - nr_dispatched, - qa->nr_reenqueued, qa->nr_reenqueued_cpu0, + qa->nr_reenqueued, qa->nr_reenqueued_cid0, qa->nr_dequeued, qa->nr_core_sched_execed, qa->nr_ddsp_from_enq); @@ -173,7 +224,7 @@ int main(int argc, char **argv) qa->nr_expedited_remote, qa->nr_expedited_from_timer, qa->nr_expedited_lost); - if (__COMPAT_has_ksym("scx_bpf_cpuperf_cur")) + if (__COMPAT_has_ksym("scx_bpf_cidperf_cur")) printf("cpuperf: cur min/avg/max=%u/%u/%u target min/avg/max=%u/%u/%u\n", qa->cpuperf_min, qa->cpuperf_avg, diff --git a/tools/sched_ext/scx_qmap.h b/tools/sched_ext/scx_qmap.h index 9d9af2ad90c6..d15a705d5ac5 100644 --- a/tools/sched_ext/scx_qmap.h +++ b/tools/sched_ext/scx_qmap.h @@ -45,7 +45,7 @@ struct qmap_fifo { struct qmap_arena { /* userspace-visible stats */ - __u64 nr_enqueued, nr_dispatched, nr_reenqueued, nr_reenqueued_cpu0; + __u64 nr_enqueued, nr_dispatched, nr_reenqueued, nr_reenqueued_cid0; __u64 nr_dequeued, nr_ddsp_from_enq; __u64 nr_core_sched_execed; __u64 nr_expedited_local, nr_expedited_remote; -- 2.54.0