From 54bc672887e986bbcfc23ea95b9d8727582a1e60 Mon Sep 17 00:00:00 2001
From: derMihai <mihairenea@gmail.com>
Date: Mon, 18 Mar 2019 19:51:50 +0100
Subject: [PATCH] Commented bugs, TODO's and things that are (at least for me)
unclear
---
kernel/sched/pb.c | 14 +++++++++++---
kernel/sched/perf_error_detection.c | 19 +++++++++++++++++--
kernel/sched/sched.h | 15 ++++++++++++++-
3 files changed, 42 insertions(+), 6 deletions(-)
diff --git a/kernel/sched/pb.c b/kernel/sched/pb.c
index 926432579cc5..ef82c517a410 100644
--- a/kernel/sched/pb.c
+++ b/kernel/sched/pb.c
@@ -122,9 +122,15 @@ static struct task_struct * pick_next_task_pb(struct rq *rq,
if (next_mode == PB_EXEC_MODE)
{
if (current_mode == PB_EXEC_MODE){
- int perf_counter = terminate_perf_event(pb->pevent, pb->plan[pb->c_entry].task_id);
+ /*
+ * !!! perf_counter contains return value of perf_event_release_kernel(), not the event counter !!!
+ */
+ // u64 pevent_cntval;
+ int perf_counter = terminate_perf_event(pb->pevent, pb->plan[pb->c_entry].task_id /*, &pevent_cntval */);
//error detection
+
if (perf_counter < pb->plan[pb->c_entry].n_instr){
+ // if (pevent_cntval < pb->plan[pb->c_entry].n_instr){
printk(KERN_WARNING "PB TASK %llu RAN TOO SHORT\n",pb->plan[pb->c_entry].task_id);
}
pb->c_entry++;
@@ -143,7 +149,7 @@ static struct task_struct * pick_next_task_pb(struct rq *rq,
}
}else if(current_mode == PB_ADMIN_MODE){
printk(KERN_DEBUG "PB ADMIN,STOP,%u,%llu\n", pb->c_entry, sched_clock());
- }else{
+ }else{ // PB_DISABLED_MODE
int perf_init_res = init_perf_event(pb->plan[pb->c_entry], &pb->pevent);
if(perf_init_res < 0){
@@ -177,7 +183,9 @@ static void set_curr_task_pb(struct rq *rq)
// NOP
}
-
+/*
+ * TODO: Make sure this does't interrupt determine_next_mode_pb() and pick_next_task_pb()
+ */
static void task_tick_pb(struct rq *rq, struct task_struct *p, int queued)
{
int next_mode;
diff --git a/kernel/sched/perf_error_detection.c b/kernel/sched/perf_error_detection.c
index 8f02f229f087..68b46e2776b6 100644
--- a/kernel/sched/perf_error_detection.c
+++ b/kernel/sched/perf_error_detection.c
@@ -3,6 +3,15 @@
#define PERF_SAMPLE_PERIOD_SIZE 100000
+/*
+ * Our understanding of perf so far. Please correct as needed.
+ *
+ * An event in perf's terms is an instruction in our case.
+ * A sample is a fixed number of events that CAN trigger a wakeup_event (but not the only way).
+ * An overflow event is triggered by a fixed number of wakeup_event.
+ *
+ */
+
//initialize perf event for new task
int init_perf_event(struct plan_entry plan_entry, struct perf_event **pevent){
struct perf_event_attr pe;
@@ -34,8 +43,14 @@ int init_perf_event(struct plan_entry plan_entry, struct perf_event **pevent){
}
//terminate perf event - return performance counter value
-long long terminate_perf_event(struct perf_event *pevent, u64 task_id){
-
+/*
+ * TODO: return the event counter value
+ *
+ */
+long long terminate_perf_event(struct perf_event *pevent, u64 task_id /*, u64 *pevent_cntval */){
+
+ // TODO:
+ // *pevent_cntval = get the counter value here
return perf_event_release_kernel(pevent);
}
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index dbbb652ab019..a451e57c0fab 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -537,7 +537,7 @@ struct pb_rq {
// currently executed entry of the plan
unsigned int c_entry;
// pointer to the dummy task
- struct task_struct *proxy_task;
+ struct task_struct *proxy_task; //TODO: We should comment this out and iterate the plan accordingly
// amount of timer consecutive timer interrupts for pb tasks
u64 n_pb_cycles;
@@ -552,6 +552,8 @@ struct pb_rq {
// one of PB_DISABLED_MODE, PB_EXEC_MODE, PB_ADMIN_MODE
int mode;
+
+ //TODO: Do we still need those?
int measure_k;
u64 kstart;
u64 ktime;
@@ -881,6 +883,11 @@ static inline int determine_next_mode_pb(struct rq *rq)
{
// initial switch
if (pb->mode == PB_DISABLED_MODE &&
+ //TODO:
+ /*
+ * We have to iterate the Plan, and think about a mechanism to signal that a plan is ready
+ * to be processed - maybe set pb->size 0 when the plan is done, n when a plan with n entries is ready.
+ */
pb->proxy_task != NULL)
{
return PB_EXEC_MODE;
@@ -890,6 +897,9 @@ static inline int determine_next_mode_pb(struct rq *rq)
if (pb->mode == PB_EXEC_MODE)
{
//stay for n timer interrupts cycles in exec mode
+ /*
+ * Is the tick interrupt active in this moment?
+ */
if(pb->count_pb_cycles > pb->n_pb_cycles){
mode = PB_ADMIN_MODE;
pb->count_pb_cycles = 0;
@@ -900,6 +910,9 @@ static inline int determine_next_mode_pb(struct rq *rq)
else if (pb->mode == PB_ADMIN_MODE)
{
//stay for n timer interrupt cylces in uall mode for admin tasks
+ /*
+ * Is the tick interrupt active in this moment?
+ */
if(pb->count_admin_cycles > pb->n_admin_cycles){
mode = PB_EXEC_MODE;
pb->count_admin_cycles = 0;
--
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