delayacct: track delays from IRQ/SOFTIRQ

Delay accounting does not track the delay of IRQ/SOFTIRQ.  While
IRQ/SOFTIRQ could have obvious impact on some workloads productivity, such
as when workloads are running on system which is busy handling network
IRQ/SOFTIRQ.

Get the delay of IRQ/SOFTIRQ could help users to reduce such delay.  Such
as setting interrupt affinity or task affinity, using kernel thread for
NAPI etc.  This is inspired by "sched/psi: Add PSI_IRQ to track
IRQ/SOFTIRQ pressure"[1].  Also fix some code indent problems of older
code.

And update tools/accounting/getdelays.c:
    / # ./getdelays -p 156 -di
    print delayacct stats ON
    printing IO accounting
    PID     156

    CPU             count     real total  virtual total    delay total  delay average
                       15       15836008       16218149      275700790         18.380ms
    IO              count    delay total  delay average
                        0              0          0.000ms
    SWAP            count    delay total  delay average
                        0              0          0.000ms
    RECLAIM         count    delay total  delay average
                        0              0          0.000ms
    THRASHING       count    delay total  delay average
                        0              0          0.000ms
    COMPACT         count    delay total  delay average
                        0              0          0.000ms
    WPCOPY          count    delay total  delay average
                       36        7586118          0.211ms
    IRQ             count    delay total  delay average
                       42         929161          0.022ms

[1] commit 52b1364ba0b1("sched/psi: Add PSI_IRQ to track IRQ/SOFTIRQ pressure")

Link: https://lkml.kernel.org/r/202304081728353557233@zte.com.cn
Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
Cc: Jiang Xuexin <jiang.xuexin@zte.com.cn>
Cc: wangyong <wang.yong12@zte.com.cn>
Cc: junhua huang <huang.junhua@zte.com.cn>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

2 files changed, 20 insertions, 1 deletions

diff --git a/include/linux/delayacct.h b/include/linux/delayacct.h
index 0da97dba9ef8..6639f48dac36 100644
--- a/include/linux/delayacct.h
+++ b/include/linux/delayacct.h
@@ -48,10 +48,13 @@ struct task_delay_info {
 	u64 wpcopy_start;
 	u64 wpcopy_delay;	/* wait for write-protect copy */
 
+	u64 irq_delay;	/* wait for IRQ/SOFTIRQ */
+
 	u32 freepages_count;	/* total count of memory reclaim */
 	u32 thrashing_count;	/* total count of thrash waits */
 	u32 compact_count;	/* total count of memory compact */
 	u32 wpcopy_count;	/* total count of write-protect copy */
+	u32 irq_count;	/* total count of IRQ/SOFTIRQ */
 };
 #endif
 
@@ -81,6 +84,7 @@ extern void __delayacct_compact_start(void);
 extern void __delayacct_compact_end(void);
 extern void __delayacct_wpcopy_start(void);
 extern void __delayacct_wpcopy_end(void);
+extern void __delayacct_irq(struct task_struct *task, u32 delta);
 
 static inline void delayacct_tsk_init(struct task_struct *tsk)
 {
@@ -215,6 +219,15 @@ static inline void delayacct_wpcopy_end(void)
 		__delayacct_wpcopy_end();
 }
 
+static inline void delayacct_irq(struct task_struct *task, u32 delta)
+{
+	if (!static_branch_unlikely(&delayacct_key))
+		return;
+
+	if (task->delays)
+		__delayacct_irq(task, delta);
+}
+
 #else
 static inline void delayacct_init(void)
 {}
@@ -253,6 +266,8 @@ static inline void delayacct_wpcopy_start(void)
 {}
 static inline void delayacct_wpcopy_end(void)
 {}
+static inline void delayacct_irq(struct task_struct *task, u32 delta)
+{}
 
 #endif /* CONFIG_TASK_DELAY_ACCT */
 
diff --git a/include/uapi/linux/taskstats.h b/include/uapi/linux/taskstats.h
index a7f5b11a8f1b..b50b2eb257a0 100644
--- a/include/uapi/linux/taskstats.h
+++ b/include/uapi/linux/taskstats.h
@@ -34,7 +34,7 @@
  */
 
 
-#define TASKSTATS_VERSION	13
+#define TASKSTATS_VERSION	14
 #define TS_COMM_LEN		32	/* should be >= TASK_COMM_LEN
 					 * in linux/sched.h */
 
@@ -198,6 +198,10 @@ struct taskstats {
 	/* v13: Delay waiting for write-protect copy */
 	__u64    wpcopy_count;
 	__u64    wpcopy_delay_total;
+
+	/* v14: Delay waiting for IRQ/SOFTIRQ */
+	__u64    irq_count;
+	__u64    irq_delay_total;
 };