From: Tejun Heo Date: Tue, 23 Sep 2025 19:03:26 +0000 (-1000) Subject: tools/sched_ext: scx_qmap: Make debug output quieter by default X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=7852e0fd1de05efadcd8b6f72140cd208c79ba56;p=users%2Fhch%2Fmisc.git tools/sched_ext: scx_qmap: Make debug output quieter by default scx_qmap currently outputs verbose debug messages including cgroup operations and CPU online/offline events by default, which can be noisy during normal operation. While the existing -P option controls DSQ dumps and event statistics, there's no way to suppress the other debug messages. Split the debug output controls to make scx_qmap quieter by default. The -P option continues to control DSQ dumps and event statistics (print_dsqs_and_events), while a new -M option controls debug messages like cgroup operations and CPU events (print_msgs). This allows users to run scx_qmap with minimal output and selectively enable debug information as needed. Acked-by: Andrea Righi Signed-off-by: Tejun Heo --- diff --git a/tools/sched_ext/scx_qmap.bpf.c b/tools/sched_ext/scx_qmap.bpf.c index cd50a94326e3..3072b593f898 100644 --- a/tools/sched_ext/scx_qmap.bpf.c +++ b/tools/sched_ext/scx_qmap.bpf.c @@ -39,7 +39,8 @@ const volatile u32 stall_kernel_nth; const volatile u32 dsp_inf_loop_after; const volatile u32 dsp_batch; const volatile bool highpri_boosting; -const volatile bool print_shared_dsq; +const volatile bool print_dsqs_and_events; +const volatile bool print_msgs; const volatile s32 disallow_tgid; const volatile bool suppress_dump; @@ -633,22 +634,25 @@ void BPF_STRUCT_OPS(qmap_dump_task, struct scx_dump_ctx *dctx, struct task_struc s32 BPF_STRUCT_OPS(qmap_cgroup_init, struct cgroup *cgrp, struct scx_cgroup_init_args *args) { - bpf_printk("CGRP INIT %llu weight=%u period=%lu quota=%ld burst=%lu", - cgrp->kn->id, args->weight, args->bw_period_us, - args->bw_quota_us, args->bw_burst_us); + if (print_msgs) + bpf_printk("CGRP INIT %llu weight=%u period=%lu quota=%ld burst=%lu", + cgrp->kn->id, args->weight, args->bw_period_us, + args->bw_quota_us, args->bw_burst_us); return 0; } void BPF_STRUCT_OPS(qmap_cgroup_set_weight, struct cgroup *cgrp, u32 weight) { - bpf_printk("CGRP SET %llu weight=%u", cgrp->kn->id, weight); + if (print_msgs) + bpf_printk("CGRP SET %llu weight=%u", cgrp->kn->id, weight); } void BPF_STRUCT_OPS(qmap_cgroup_set_bandwidth, struct cgroup *cgrp, u64 period_us, u64 quota_us, u64 burst_us) { - bpf_printk("CGRP SET %llu period=%lu quota=%ld burst=%lu", cgrp->kn->id, - period_us, quota_us, burst_us); + if (print_msgs) + bpf_printk("CGRP SET %llu period=%lu quota=%ld burst=%lu", + cgrp->kn->id, period_us, quota_us, burst_us); } /* @@ -692,16 +696,20 @@ static void print_cpus(void) void BPF_STRUCT_OPS(qmap_cpu_online, s32 cpu) { - bpf_printk("CPU %d coming online", cpu); - /* @cpu is already online at this point */ - print_cpus(); + if (print_msgs) { + bpf_printk("CPU %d coming online", cpu); + /* @cpu is already online at this point */ + print_cpus(); + } } void BPF_STRUCT_OPS(qmap_cpu_offline, s32 cpu) { - bpf_printk("CPU %d going offline", cpu); - /* @cpu is still online at this point */ - print_cpus(); + if (print_msgs) { + bpf_printk("CPU %d going offline", cpu); + /* @cpu is still online at this point */ + print_cpus(); + } } struct monitor_timer { @@ -799,35 +807,36 @@ static void dump_shared_dsq(void) static int monitor_timerfn(void *map, int *key, struct bpf_timer *timer) { - struct scx_event_stats events; - bpf_rcu_read_lock(); dispatch_highpri(true); bpf_rcu_read_unlock(); monitor_cpuperf(); - if (print_shared_dsq) + if (print_dsqs_and_events) { + struct scx_event_stats events; + dump_shared_dsq(); - __COMPAT_scx_bpf_events(&events, sizeof(events)); - - bpf_printk("%35s: %lld", "SCX_EV_SELECT_CPU_FALLBACK", - scx_read_event(&events, SCX_EV_SELECT_CPU_FALLBACK)); - bpf_printk("%35s: %lld", "SCX_EV_DISPATCH_LOCAL_DSQ_OFFLINE", - scx_read_event(&events, SCX_EV_DISPATCH_LOCAL_DSQ_OFFLINE)); - bpf_printk("%35s: %lld", "SCX_EV_DISPATCH_KEEP_LAST", - scx_read_event(&events, SCX_EV_DISPATCH_KEEP_LAST)); - bpf_printk("%35s: %lld", "SCX_EV_ENQ_SKIP_EXITING", - scx_read_event(&events, SCX_EV_ENQ_SKIP_EXITING)); - bpf_printk("%35s: %lld", "SCX_EV_REFILL_SLICE_DFL", - scx_read_event(&events, SCX_EV_REFILL_SLICE_DFL)); - bpf_printk("%35s: %lld", "SCX_EV_BYPASS_DURATION", - scx_read_event(&events, SCX_EV_BYPASS_DURATION)); - bpf_printk("%35s: %lld", "SCX_EV_BYPASS_DISPATCH", - scx_read_event(&events, SCX_EV_BYPASS_DISPATCH)); - bpf_printk("%35s: %lld", "SCX_EV_BYPASS_ACTIVATE", - scx_read_event(&events, SCX_EV_BYPASS_ACTIVATE)); + __COMPAT_scx_bpf_events(&events, sizeof(events)); + + bpf_printk("%35s: %lld", "SCX_EV_SELECT_CPU_FALLBACK", + scx_read_event(&events, SCX_EV_SELECT_CPU_FALLBACK)); + bpf_printk("%35s: %lld", "SCX_EV_DISPATCH_LOCAL_DSQ_OFFLINE", + scx_read_event(&events, SCX_EV_DISPATCH_LOCAL_DSQ_OFFLINE)); + bpf_printk("%35s: %lld", "SCX_EV_DISPATCH_KEEP_LAST", + scx_read_event(&events, SCX_EV_DISPATCH_KEEP_LAST)); + bpf_printk("%35s: %lld", "SCX_EV_ENQ_SKIP_EXITING", + scx_read_event(&events, SCX_EV_ENQ_SKIP_EXITING)); + bpf_printk("%35s: %lld", "SCX_EV_REFILL_SLICE_DFL", + scx_read_event(&events, SCX_EV_REFILL_SLICE_DFL)); + bpf_printk("%35s: %lld", "SCX_EV_BYPASS_DURATION", + scx_read_event(&events, SCX_EV_BYPASS_DURATION)); + bpf_printk("%35s: %lld", "SCX_EV_BYPASS_DISPATCH", + scx_read_event(&events, SCX_EV_BYPASS_DISPATCH)); + bpf_printk("%35s: %lld", "SCX_EV_BYPASS_ACTIVATE", + scx_read_event(&events, SCX_EV_BYPASS_ACTIVATE)); + } bpf_timer_start(timer, ONE_SEC_IN_NS, 0); return 0; @@ -839,7 +848,8 @@ s32 BPF_STRUCT_OPS_SLEEPABLE(qmap_init) struct bpf_timer *timer; s32 ret; - print_cpus(); + if (print_msgs) + print_cpus(); ret = scx_bpf_create_dsq(SHARED_DSQ, -1); if (ret) diff --git a/tools/sched_ext/scx_qmap.c b/tools/sched_ext/scx_qmap.c index c4912ab2e76f..ef701d45ba43 100644 --- a/tools/sched_ext/scx_qmap.c +++ b/tools/sched_ext/scx_qmap.c @@ -20,7 +20,7 @@ const char help_fmt[] = "See the top-level comment in .bpf.c for more details.\n" "\n" "Usage: %s [-s SLICE_US] [-e COUNT] [-t COUNT] [-T COUNT] [-l COUNT] [-b COUNT]\n" -" [-P] [-d PID] [-D LEN] [-p] [-v]\n" +" [-P] [-M] [-d PID] [-D LEN] [-p] [-v]\n" "\n" " -s SLICE_US Override slice duration\n" " -e COUNT Trigger scx_bpf_error() after COUNT enqueues\n" @@ -28,7 +28,8 @@ const char help_fmt[] = " -T COUNT Stall every COUNT'th kernel thread\n" " -l COUNT Trigger dispatch infinite looping after COUNT dispatches\n" " -b COUNT Dispatch upto COUNT tasks together\n" -" -P Print out DSQ content to trace_pipe every second, use with -b\n" +" -P Print out DSQ content and event counters to trace_pipe every second\n" +" -M Print out debug messages to trace_pipe\n" " -H Boost nice -20 tasks in SHARED_DSQ, use with -b\n" " -d PID Disallow a process from switching into SCHED_EXT (-1 for self)\n" " -D LEN Set scx_exit_info.dump buffer length\n" @@ -66,7 +67,7 @@ int main(int argc, char **argv) skel->rodata->slice_ns = __COMPAT_ENUM_OR_ZERO("scx_public_consts", "SCX_SLICE_DFL"); - while ((opt = getopt(argc, argv, "s:e:t:T:l:b:PHd:D:Spvh")) != -1) { + while ((opt = getopt(argc, argv, "s:e:t:T:l:b:PMHd:D:Spvh")) != -1) { switch (opt) { case 's': skel->rodata->slice_ns = strtoull(optarg, NULL, 0) * 1000; @@ -87,7 +88,10 @@ int main(int argc, char **argv) skel->rodata->dsp_batch = strtoul(optarg, NULL, 0); break; case 'P': - skel->rodata->print_shared_dsq = true; + skel->rodata->print_dsqs_and_events = true; + break; + case 'M': + skel->rodata->print_msgs = true; break; case 'H': skel->rodata->highpri_boosting = true;