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
+ * cpu_to_cid array to exercise the kfunc's acceptance and error paths.
+ *
+ * 0 = disabled
+ * 1 = valid reverse mapping
+ * 2 = invalid: duplicate cid assignment
+ * 3 = invalid: out-of-range cid
+ */
+const volatile u32 cid_override_mode;
+/*
+ * Array lives 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
+ * it before SCX_OPS_LOAD, same as rodata, and nothing writes it after.
+ */
+s32 cid_override_cpu_to_cid[SCX_QMAP_MAX_CPUS];
+
UEI_DEFINE(uei);
/*
}
/*
- * 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) {
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;
}
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;
}
}
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) {
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) {
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;
}
* 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;
}
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) {
}
/*
- * 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 {
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;
}
}
- 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. */
* 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--;
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;
/*
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);
}
/*
}
}
-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;
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 {
} 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();
+ s32 cid;
- bpf_for(i, 0, nr_cpu_ids) {
- struct cpu_ctx __arena *cpuc = &qa.cpu_ctxs[i];
- u32 cap, cur;
-
- 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);
}
/*
{
u8 __arena *slab;
u32 nr_pages, key = 0, i;
+ u32 nr_cids, nr_cpu_ids;
struct bpf_timer *timer;
s32 ret;
- if (scx_bpf_nr_cids() > SCX_QMAP_MAX_CPUS) {
+ nr_cids = scx_bpf_nr_cids();
+ nr_cpu_ids = scx_bpf_nr_cpu_ids();
+
+ if (nr_cids > SCX_QMAP_MAX_CPUS) {
scx_bpf_error("nr_cids=%u exceeds SCX_QMAP_MAX_CPUS=%d",
- scx_bpf_nr_cids(), SCX_QMAP_MAX_CPUS);
+ nr_cids, SCX_QMAP_MAX_CPUS);
return -EINVAL;
}
+ if (nr_cpu_ids > SCX_QMAP_MAX_CPUS) {
+ scx_bpf_error("nr_cpu_ids=%u exceeds SCX_QMAP_MAX_CPUS=%d",
+ nr_cpu_ids, SCX_QMAP_MAX_CPUS);
+ 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,
+ nr_cpu_ids * sizeof(s32));
+ }
/*
* Allocate the task_ctx slab in arena and thread the entire slab onto
scx_bpf_error("failed to allocate idle cmask");
return -ENOMEM;
}
- cmask_init(qa_idle_cids, 0, scx_bpf_nr_cids());
+ cmask_init(qa_idle_cids, 0, nr_cids);
ret = scx_bpf_create_dsq(SHARED_DSQ, -1);
if (ret) {
}
}
-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,
" -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-range)\n"
" -v Print libbpf debug messages\n"
" -h Display this help and exit\n";
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);
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;
case 'F':
skel->rodata->immed_stress_nth = strtoul(optarg, NULL, 0);
break;
+ case 'C': {
+ u32 nr_cpus = libbpf_num_possible_cpus();
+ u32 mode, i;
+
+ if (!strcmp(optarg, "shuffle"))
+ mode = 1;
+ else if (!strcmp(optarg, "bad-dup"))
+ mode = 2;
+ else if (!strcmp(optarg, "bad-range"))
+ mode = 3;
+ else {
+ fprintf(stderr, "unknown cid-override mode '%s'\n", optarg);
+ return 1;
+ }
+ skel->rodata->cid_override_mode = mode;
+
+ /* shuffle: reversed cpu_to_cid, bad-dup: dup cid 0, bad-range: 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;
+ if (mode == 3)
+ skel->bss->cid_override_cpu_to_cid[0] = (s32)nr_cpus;
+ break;
+ }
case 'v':
verbose = true;
break;
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);
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,
projects / thirdparty / linux.git / commitdiff
