Remove incorrect cgroup filtering from runqlat (#201)

* Initial plan

* Fix incorrect cgroup filtering in runqlat - remove checks for waker instead of wakee

Co-authored-by: yunwei37 <34985212+yunwei37@users.noreply.github.com>

* Clarify that filter_cg is deprecated and has no effect

Co-authored-by: yunwei37 <34985212+yunwei37@users.noreply.github.com>

* Update docs to show DEPRECATED comment in code snippets and mention --filter_cg is no-op

Co-authored-by: yunwei37 <34985212+yunwei37@users.noreply.github.com>

* Remove filter_cg and cgroup_map completely from code and docs

Co-authored-by: yunwei37 <34985212+yunwei37@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: yunwei37 <34985212+yunwei37@users.noreply.github.com>

Author: Copilot

src/9-runqlat/README.md

@@ -67,20 +67,12 @@ First, we need to write a source code file `runqlat.bpf.c`:
 #define MAX_ENTRIES 10240
 #define TASK_RUNNING  0
 
-const volatile bool filter_cg = false;
 const volatile bool targ_per_process = false;
 const volatile bool targ_per_thread = false;
 const volatile bool targ_per_pidns = false;
 const volatile bool targ_ms = false;
 const volatile pid_t targ_tgid = 0;
 
-struct {
- __uint(type, BPF_MAP_TYPE_CGROUP_ARRAY);
- __type(key, u32);
- __type(value, u32);
- __uint(max_entries, 1);
-} cgroup_map SEC(".maps");
-
 struct {
  __uint(type, BPF_MAP_TYPE_HASH);
  __uint(max_entries, MAX_ENTRIES);
@@ -137,9 +129,6 @@ u64 *tsp, slot;
 u32 pid, hkey;
 s64 delta;
 
-if (filter_cg && !bpf_current_task_under_cgroup(&cgroup_map, 0))
-  return 0;
-
 if (get_task_state(prev) == TASK_RUNNING)
   trace_enqueue(BPF_CORE_READ(prev, tgid), BPF_CORE_READ(prev, pid));
 
@@ -183,18 +172,12 @@ return 0;
 SEC("raw_tp/sched_wakeup")
 int BPF_PROG(handle_sched_wakeup, struct task_struct *p)
 {
- if (filter_cg && !bpf_current_task_under_cgroup(&cgroup_map, 0))
-  return 0;
-
  return trace_enqueue(BPF_CORE_READ(p, tgid), BPF_CORE_READ(p, pid));
 }
 
 SEC("raw_tp/sched_wakeup_new")
 int BPF_PROG(handle_sched_wakeup_new, struct task_struct *p)
 {
- if (filter_cg && !bpf_current_task_under_cgroup(&cgroup_map, 0))
-  return 0;
-
  return trace_enqueue(BPF_CORE_READ(p, tgid), BPF_CORE_READ(p, pid));
 }
 
@@ -215,7 +198,6 @@ The code defines several constants and volatile global variables used for filter
 #define MAX_ENTRIES 10240
 #define TASK_RUNNING  0
 
-const volatile bool filter_cg = false;
 const volatile bool targ_per_process = false;
 const volatile bool targ_per_thread = false;
 const volatile bool targ_per_pidns = false;
@@ -225,20 +207,13 @@ const volatile pid_t targ_tgid = 0;
 
 - `MAX_ENTRIES`: The maximum number of map entries.
 - `TASK_RUNNING`: The task status value.
-- `filter_cg`, `targ_per_process`, `targ_per_thread`, `targ_per_pidns`, `targ_ms`, `targ_tgid`: Boolean variables for filtering and target options. These options can be set by user-space programs to customize the behavior of the eBPF program.
+- `targ_per_process`, `targ_per_thread`, `targ_per_pidns`, `targ_ms`, `targ_tgid`: Boolean variables for filtering and target options. These options can be set by user-space programs to customize the behavior of the eBPF program.
 
 #### eBPF Maps
 
 The code defines several eBPF maps including:
 
 ```c
-struct {
- __uint(type, BPF_MAP_TYPE_CGROUP_ARRAY);
- __type(key, u32);
- __type(value, u32);
- __uint(max_entries, 1);
-} cgroup_map SEC(".maps");
-
 struct {
  __uint(type, BPF_MAP_TYPE_HASH);
  __uint(max_entries, MAX_ENTRIES);
@@ -256,7 +231,6 @@ struct {
 } hists SEC(".maps");
 ```
 
-- `cgroup_map`: A cgroup array map used for filtering cgroups.
 - `start`: A hash map used to store timestamps when processes are enqueued.
 - `hists`: A hash map used to store histogram data for recording process scheduling delays.
 
@@ -313,7 +287,7 @@ static int handle_switch(bool preempt, struct task_struct *prev, struct task_str
 }
 ```
 
-Firstly, the function determines whether to filter cgroup based on the setting of `filter_cg`. Then, if the previous process state is `TASK_RUNNING`, the `trace_enqueue` function is called to record the enqueue time of the process. Then, the function looks up the enqueue timestamp of the next process. If it is not found, it returns directly. The scheduling latency (delta) is calculated, and the key for the histogram map (hkey) is determined based on different options (targ_per_process, targ_per_thread, targ_per_pidns). Then, the histogram map is looked up or initialized, and the histogram data is updated. Finally, the enqueue timestamp record of the process is deleted.
+If the previous process state is `TASK_RUNNING`, the `trace_enqueue` function is called to record the enqueue time of the process. Then, the function looks up the enqueue timestamp of the next process. If it is not found, it returns directly. The scheduling latency (delta) is calculated, and the key for the histogram map (hkey) is determined based on different options (targ_per_process, targ_per_thread, targ_per_pidns). Then, the histogram map is looked up or initialized, and the histogram data is updated. Finally, the enqueue timestamp record of the process is deleted.
 
 Next is the entry point of the eBPF program. The program uses three entry points to capture different scheduling events:
 
@@ -374,15 +348,14 @@ Run:
 
 ```console
 $ sudo ecli run examples/bpftools/runqlat/package.json -h
-Usage: runqlat_bpf [--help] [--version] [--verbose] [--filter_cg] [--targ_per_process] [--targ_per_thread] [--targ_per_pidns] [--targ_ms] [--targ_tgid VAR]
+Usage: runqlat_bpf [--help] [--version] [--verbose] [--targ_per_process] [--targ_per_thread] [--targ_per_pidns] [--targ_ms] [--targ_tgid VAR]
 
 A simple eBPF program
 
 Optional arguments:
 -h, --help            shows help message and exits 
 -v, --version         prints version information and exits 
 --verbose             prints libbpf debug information 
---filter_cg           set value of bool variable filter_cg 
 --targ_per_process    set value of bool variable targ_per_process 
 --targ_per_thread     set value of bool variable targ_per_thread 
 --targ_per_pidns      set value of bool variable targ_per_pidns 

src/9-runqlat/README.zh.md

@@ -70,20 +70,12 @@ runqlat 的实现利用了 eBPF 程序，它通过内核跟踪点和函数探针
 #define MAX_ENTRIES 10240
 #define TASK_RUNNING  0
 
-const volatile bool filter_cg = false;
 const volatile bool targ_per_process = false;
 const volatile bool targ_per_thread = false;
 const volatile bool targ_per_pidns = false;
 const volatile bool targ_ms = false;
 const volatile pid_t targ_tgid = 0;
 
-struct {
- __uint(type, BPF_MAP_TYPE_CGROUP_ARRAY);
- __type(key, u32);
- __type(value, u32);
- __uint(max_entries, 1);
-} cgroup_map SEC(".maps");
-
 struct {
  __uint(type, BPF_MAP_TYPE_HASH);
  __uint(max_entries, MAX_ENTRIES);
@@ -140,9 +132,6 @@ static int handle_switch(bool preempt, struct task_struct *prev, struct task_str
  u32 pid, hkey;
  s64 delta;
 
- if (filter_cg && !bpf_current_task_under_cgroup(&cgroup_map, 0))
-  return 0;
-
  if (get_task_state(prev) == TASK_RUNNING)
   trace_enqueue(BPF_CORE_READ(prev, tgid), BPF_CORE_READ(prev, pid));
 
@@ -186,18 +175,12 @@ cleanup:
 SEC("raw_tp/sched_wakeup")
 int BPF_PROG(handle_sched_wakeup, struct task_struct *p)
 {
- if (filter_cg && !bpf_current_task_under_cgroup(&cgroup_map, 0))
-  return 0;
-
  return trace_enqueue(BPF_CORE_READ(p, tgid), BPF_CORE_READ(p, pid));
 }
 
 SEC("raw_tp/sched_wakeup_new")
 int BPF_PROG(handle_sched_wakeup_new, struct task_struct *p)
 {
- if (filter_cg && !bpf_current_task_under_cgroup(&cgroup_map, 0))
-  return 0;
-
  return trace_enqueue(BPF_CORE_READ(p, tgid), BPF_CORE_READ(p, pid));
 }
 
@@ -218,7 +201,6 @@ char LICENSE[] SEC("license") = "GPL";
 #define MAX_ENTRIES 10240
 #define TASK_RUNNING  0
 
-const volatile bool filter_cg = false;
 const volatile bool targ_per_process = false;
 const volatile bool targ_per_thread = false;
 const volatile bool targ_per_pidns = false;
@@ -228,20 +210,13 @@ const volatile pid_t targ_tgid = 0;
 
 - `MAX_ENTRIES`:  map 条目最大数量
 - `TASK_RUNNING`: 任务状态值
-- `filter_cg`, `targ_per_process`, `targ_per_thread`, `targ_per_pidns`, `targ_ms`, `targ_tgid`: 用于过滤选项和目标选项的布尔变量。这些选项可以通过用户空间程序设置来自定义eBPF程序的行为。
+- `targ_per_process`, `targ_per_thread`, `targ_per_pidns`, `targ_ms`, `targ_tgid`: 用于过滤选项和目标选项的布尔变量。这些选项可以通过用户空间程序设置来自定义eBPF程序的行为.
 
 #### eBPF Maps 映射
 
 接下来，定义了一些 eBPF 映射：
 
 ```c
-struct {
- __uint(type, BPF_MAP_TYPE_CGROUP_ARRAY);
- __type(key, u32);
- __type(value, u32);
- __uint(max_entries, 1);
-} cgroup_map SEC(".maps");
-
 struct {
  __uint(type, BPF_MAP_TYPE_HASH);
  __uint(max_entries, MAX_ENTRIES);
@@ -261,7 +236,6 @@ struct {
 
 这些映射包括：
 
-- `cgroup_map` 用于过滤 cgroup；
 - `start` 用于存储进程入队时的时间戳；
 - `hists` 用于存储直方图数据，记录进程调度延迟。
 
@@ -318,7 +292,7 @@ static int handle_switch(bool preempt, struct task_struct *prev, struct task_str
 }
 ```
 
-首先，函数根据 `filter_cg` 的设置判断是否需要过滤 cgroup。然后，如果之前的进程状态为 `TASK_RUNNING`，则调用 `trace_enqueue` 函数记录进程的入队时间。接着，函数查找下一个进程的入队时间戳，如果找不到，直接返回。计算调度延迟（delta），并根据不同的选项设置（targ_per_process，targ_per_thread，targ_per_pidns），确定直方图映射的键（hkey）。然后查找或初始化直方图映射，更新直方图数据，最后删除进程的入队时间戳记录。
+如果之前的进程状态为 `TASK_RUNNING`，则调用 `trace_enqueue` 函数记录进程的入队时间。接着，函数查找下一个进程的入队时间戳，如果找不到，直接返回。计算调度延迟（delta），并根据不同的选项设置（targ_per_process，targ_per_thread，targ_per_pidns），确定直方图映射的键（hkey）。然后查找或初始化直方图映射，更新直方图数据，最后删除进程的入队时间戳记录。
 
 接下来是 eBPF 程序的入口点。程序使用三个入口点来捕获不同的调度事件：
 
@@ -379,15 +353,14 @@ Run:
 
 ```console
 $ sudo ecli run examples/bpftools/runqlat/package.json -h
-Usage: runqlat_bpf [--help] [--version] [--verbose] [--filter_cg] [--targ_per_process] [--targ_per_thread] [--targ_per_pidns] [--targ_ms] [--targ_tgid VAR]
+Usage: runqlat_bpf [--help] [--version] [--verbose] [--targ_per_process] [--targ_per_thread] [--targ_per_pidns] [--targ_ms] [--targ_tgid VAR]
 
 A simple eBPF program
 
 Optional arguments:
   -h, --help            shows help message and exits 
   -v, --version         prints version information and exits 
   --verbose             prints libbpf debug information 
-  --filter_cg           set value of bool variable filter_cg 
   --targ_per_process    set value of bool variable targ_per_process 
   --targ_per_thread     set value of bool variable targ_per_thread 
   --targ_per_pidns      set value of bool variable targ_per_pidns 

src/9-runqlat/runqlat.bpf.c

@@ -12,20 +12,12 @@
 #define MAX_ENTRIES	10240
 #define TASK_RUNNING 	0
 
-const volatile bool filter_cg = false;
 const volatile bool targ_per_process = false;
 const volatile bool targ_per_thread = false;
 const volatile bool targ_per_pidns = false;
 const volatile bool targ_ms = false;
 const volatile pid_t targ_tgid = 0;
 
-struct {
-	__uint(type, BPF_MAP_TYPE_CGROUP_ARRAY);
-	__type(key, u32);
-	__type(value, u32);
-	__uint(max_entries, 1);
-} cgroup_map SEC(".maps");
-
 struct {
 	__uint(type, BPF_MAP_TYPE_HASH);
 	__uint(max_entries, MAX_ENTRIES);
@@ -82,9 +74,6 @@ static int handle_switch(bool preempt, struct task_struct *prev, struct task_str
 	u32 pid, hkey;
 	s64 delta;
 
-	if (filter_cg && !bpf_current_task_under_cgroup(&cgroup_map, 0))
-		return 0;
-
 	if (get_task_state(prev) == TASK_RUNNING)
 		trace_enqueue(BPF_CORE_READ(prev, tgid), BPF_CORE_READ(prev, pid));
 
@@ -128,18 +117,12 @@ static int handle_switch(bool preempt, struct task_struct *prev, struct task_str
 SEC("raw_tp/sched_wakeup")
 int BPF_PROG(handle_sched_wakeup, struct task_struct *p)
 {
-	if (filter_cg && !bpf_current_task_under_cgroup(&cgroup_map, 0))
-		return 0;
-
 	return trace_enqueue(BPF_CORE_READ(p, tgid), BPF_CORE_READ(p, pid));
 }
 
 SEC("raw_tp/sched_wakeup_new")
 int BPF_PROG(handle_sched_wakeup_new, struct task_struct *p)
 {
-	if (filter_cg && !bpf_current_task_under_cgroup(&cgroup_map, 0))
-		return 0;
-
 	return trace_enqueue(BPF_CORE_READ(p, tgid), BPF_CORE_READ(p, pid));
 }