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Merge pull request #349 from multics69/lavd-suspend-resume

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scx_lavd: properly calculate task's runtime after suspend/resume
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Changwoo Min 2024-06-13 07:57:46 +09:00 committed by GitHub
commit 1bd2c2206f
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2 changed files with 61 additions and 17 deletions
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7
scheds/rust/scx_lavd/src/bpf/intf.h
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@ -141,6 +141,12 @@ struct cpu_ctx {
volatile u64 load_run_time_ns; /* total runtime of runnable tasks */
volatile u64 last_kick_clk; /* when the CPU was kicked */
/*
* Information for cpu hotplug
*/
u64 online_clk; /* when a CPU becomes online */
u64 offline_clk; /* when a CPU becomes offline */
/*
* Information used to keep track of latency criticality
*/
@ -165,7 +171,6 @@ struct cpu_ctx {
/*
* Fields for core compaction
*
* NOTE: The followings MUST be placed at the end of this struct.
*/
struct bpf_cpumask __kptr *tmp_a_mask; /* temporary cpu mask */
struct bpf_cpumask __kptr *tmp_o_mask; /* temporary cpu mask */

71
scheds/rust/scx_lavd/src/bpf/main.bpf.c
View File

@ -1460,6 +1460,33 @@ static u64 calc_time_slice(struct task_struct *p, struct task_ctx *taskc)
return slice;
}
static void reset_suspended_duration(struct cpu_ctx *cpuc)
{
if (cpuc->online_clk > cpuc->offline_clk)
cpuc->offline_clk = cpuc->online_clk;
}
static u64 get_suspended_duration_and_reset(struct cpu_ctx *cpuc)
{
/*
* When a system is suspended, a task is also suspended in a running
* stat on the CPU. Hence, we subtract the suspended duration when it
* resumes.
*/
u64 duration = 0;
if (cpuc->online_clk > cpuc->offline_clk) {
duration = cpuc->online_clk - cpuc->offline_clk;
/*
* Once calculated, reset the duration to zero.
*/
cpuc->offline_clk = cpuc->online_clk;
}
return duration;
}
static void update_stat_for_runnable(struct task_struct *p,
struct task_ctx *taskc,
struct cpu_ctx *cpuc)
@ -1495,7 +1522,7 @@ static void update_stat_for_running(struct task_struct *p,
/*
* Update per-CPU latency criticality information for ever-scheduled
* tasks
* tasks.
*/
if (cpuc->max_lat_cri < taskc->lat_cri)
cpuc->max_lat_cri = taskc->lat_cri;
@ -1504,6 +1531,12 @@ static void update_stat_for_running(struct task_struct *p,
cpuc->sum_lat_cri += taskc->lat_cri;
cpuc->sched_nr++;
/*
* It is clear there is no need to consider the suspended duration
* while running a task, so reset the suspended duration to zero.
*/
reset_suspended_duration(cpuc);
/*
* Update task's performance criticality
*
@ -1538,7 +1571,7 @@ static void update_stat_for_stopping(struct task_struct *p,
struct cpu_ctx *cpuc)
{
u64 now = bpf_ktime_get_ns();
u64 old_run_time_ns;
u64 old_run_time_ns, suspended_duration;
/*
* Update task's run_time. When a task is scheduled consecutively
@ -1550,7 +1583,9 @@ static void update_stat_for_stopping(struct task_struct *p,
* calculation of runtime statistics.
*/
old_run_time_ns = taskc->run_time_ns;
taskc->acc_run_time_ns += now - taskc->last_running_clk;
suspended_duration = get_suspended_duration_and_reset(cpuc);
taskc->acc_run_time_ns += now - taskc->last_running_clk -
suspended_duration;
taskc->run_time_ns = calc_avg(taskc->run_time_ns,
taskc->acc_run_time_ns);
taskc->last_stopping_clk = now;
@ -2521,21 +2556,23 @@ void BPF_STRUCT_OPS(lavd_quiescent, struct task_struct *p, u64 deq_flags)
taskc->last_quiescent_clk = now;
}
static void cpu_ctx_init_online(struct cpu_ctx *cpuc, u32 cpu_id)
static void cpu_ctx_init_online(struct cpu_ctx *cpuc, u32 cpu_id, u64 now)
{
memset(cpuc, 0, sizeof(*cpuc) - 2 * sizeof(struct bpf_cpumask *));
cpuc->idle_start_clk = 0;
cpuc->cpu_id = cpu_id;
cpuc->lat_prio = LAVD_LAT_PRIO_IDLE;
cpuc->stopping_tm_est_ns = LAVD_TIME_INFINITY_NS;
WRITE_ONCE(cpuc->online_clk, now);
barrier();
cpuc->is_online = true;
}
static void cpu_ctx_init_offline(struct cpu_ctx *cpuc, u32 cpu_id)
static void cpu_ctx_init_offline(struct cpu_ctx *cpuc, u32 cpu_id, u64 now)
{
memset(cpuc, 0, sizeof(*cpuc) - 2 * sizeof(struct bpf_cpumask *));
cpuc->idle_start_clk = 0;
cpuc->cpu_id = cpu_id;
WRITE_ONCE(cpuc->offline_clk, now);
cpuc->is_online = false;
barrier();
@ -2549,13 +2586,14 @@ void BPF_STRUCT_OPS(lavd_cpu_online, s32 cpu)
* When a cpu becomes online, reset its cpu context and trigger the
* recalculation of the global cpu load.
*/
u64 now = bpf_ktime_get_ns();
struct cpu_ctx *cpuc;
cpuc = get_cpu_ctx_id(cpu);
if (!cpuc)
return;
cpu_ctx_init_online(cpuc, cpu);
cpu_ctx_init_online(cpuc, cpu, now);
__sync_fetch_and_add(&nr_cpus_onln, 1);
update_sys_stat();
@ -2567,13 +2605,14 @@ void BPF_STRUCT_OPS(lavd_cpu_offline, s32 cpu)
* When a cpu becomes offline, trigger the recalculation of the global
* cpu load.
*/
u64 now = bpf_ktime_get_ns();
struct cpu_ctx *cpuc;
cpuc = get_cpu_ctx_id(cpu);
if (!cpuc)
return;
cpu_ctx_init_offline(cpuc, cpu);
cpu_ctx_init_offline(cpuc, cpu, now);
__sync_fetch_and_sub(&nr_cpus_onln, 1);
update_sys_stat();
@ -2716,7 +2755,7 @@ out:
return err;
}
static s32 init_per_cpu_ctx(void)
static s32 init_per_cpu_ctx(u64 now)
{
int cpu;
int err;
@ -2736,21 +2775,20 @@ static s32 init_per_cpu_ctx(void)
if (err)
return err;
cpu_ctx_init_online(cpuc, cpu);
cpu_ctx_init_online(cpuc, cpu, now);
cpuc->offline_clk = now;
}
return 0;
}
static s32 init_sys_stat(void)
static s32 init_sys_stat(u64 now)
{
struct bpf_timer *timer;
u64 now;
u32 key = 0;
int err;
memset(__sys_stats, 0, sizeof(__sys_stats));
now = bpf_ktime_get_ns();
__sys_stats[0].last_update_clk = now;
__sys_stats[1].last_update_clk = now;
__sys_stats[0].nr_active = nr_cpus_onln;
@ -2774,6 +2812,7 @@ static s32 init_sys_stat(void)
s32 BPF_STRUCT_OPS_SLEEPABLE(lavd_init)
{
u64 now = bpf_ktime_get_ns();
int err;
/*
@ -2788,7 +2827,7 @@ s32 BPF_STRUCT_OPS_SLEEPABLE(lavd_init)
/*
* Initialize per-CPU context.
*/
err = init_per_cpu_ctx();
err = init_per_cpu_ctx(now);
if (err)
return err;
@ -2796,7 +2835,7 @@ s32 BPF_STRUCT_OPS_SLEEPABLE(lavd_init)
* Initialize the last update clock and the update timer to track
* system-wide CPU load.
*/
err = init_sys_stat();
err = init_sys_stat(now);
if (err)
return err;