Commit 7852e0fd authored by Tejun Heo's avatar Tejun Heo
Browse files

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: default avatarAndrea Righi <arighi@nvidia.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent d4529728

tools/sched_ext/scx_qmap.bpf.c

+45 −35
Original line number Diff line number Diff line
@@ -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;
@@ -633,6 +634,7 @@ 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)

{

	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);
@@ -641,14 +643,16 @@ s32 BPF_STRUCT_OPS(qmap_cgroup_init, struct cgroup *cgrp, struct scx_cgroup_init 


void BPF_STRUCT_OPS(qmap_cgroup_set_weight, struct cgroup *cgrp, u32 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);

}



/*
@@ -692,17 +696,21 @@ static void print_cpus(void) 


void BPF_STRUCT_OPS(qmap_cpu_online, s32 cpu)

{

	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)

{

	if (print_msgs) {

		bpf_printk("CPU %d going offline", cpu);

		/* @cpu is still online at this point */

		print_cpus();

	}

}



struct monitor_timer {

	struct bpf_timer timer;
@@ -799,15 +807,15 @@ 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));
@@ -828,6 +836,7 @@ static int monitor_timerfn(void *map, int *key, struct bpf_timer *timer) 
			   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;
@@ -839,6 +848,7 @@ s32 BPF_STRUCT_OPS_SLEEPABLE(qmap_init) 
	struct bpf_timer *timer;

	s32 ret;



	if (print_msgs)

		print_cpus();



	ret = scx_bpf_create_dsq(SHARED_DSQ, -1);

tools/sched_ext/scx_qmap.c

+8 −4
Original line number Diff line number Diff line
@@ -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;