From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/kernel/trace/trace_hwlat.c | 52 ++++++++++++++++++++++++++++++++--------------------
1 files changed, 32 insertions(+), 20 deletions(-)
diff --git a/kernel/kernel/trace/trace_hwlat.c b/kernel/kernel/trace/trace_hwlat.c
index 164e5c6..d071fc2 100644
--- a/kernel/kernel/trace/trace_hwlat.c
+++ b/kernel/kernel/trace/trace_hwlat.c
@@ -1,6 +1,6 @@
// SPDX-License-Identifier: GPL-2.0
/*
- * trace_hwlatdetect.c - A simple Hardware Latency detector.
+ * trace_hwlat.c - A simple Hardware Latency detector.
*
* Use this tracer to detect large system latencies induced by the behavior of
* certain underlying system hardware or firmware, independent of Linux itself.
@@ -83,6 +83,7 @@
u64 nmi_total_ts; /* Total time spent in NMIs */
struct timespec64 timestamp; /* wall time */
int nmi_count; /* # NMIs during this sample */
+ int count; /* # of iteratons over threash */
};
/* keep the global state somewhere. */
@@ -104,7 +105,7 @@
{
struct trace_array *tr = hwlat_trace;
struct trace_event_call *call = &event_hwlat;
- struct ring_buffer *buffer = tr->trace_buffer.buffer;
+ struct trace_buffer *buffer = tr->array_buffer.buffer;
struct ring_buffer_event *event;
struct hwlat_entry *entry;
unsigned long flags;
@@ -124,6 +125,7 @@
entry->timestamp = sample->timestamp;
entry->nmi_total_ts = sample->nmi_total_ts;
entry->nmi_count = sample->nmi_count;
+ entry->count = sample->count;
if (!call_filter_check_discard(call, entry, buffer, event))
trace_buffer_unlock_commit_nostack(buffer, event);
@@ -167,12 +169,14 @@
static int get_sample(void)
{
struct trace_array *tr = hwlat_trace;
+ struct hwlat_sample s;
time_type start, t1, t2, last_t2;
- s64 diff, total, last_total = 0;
+ s64 diff, outer_diff, total, last_total = 0;
u64 sample = 0;
u64 thresh = tracing_thresh;
u64 outer_sample = 0;
int ret = -1;
+ unsigned int count = 0;
do_div(thresh, NSEC_PER_USEC); /* modifies interval value */
@@ -186,6 +190,7 @@
init_time(last_t2, 0);
start = time_get(); /* start timestamp */
+ outer_diff = 0;
do {
@@ -194,14 +199,14 @@
if (time_u64(last_t2)) {
/* Check the delta from outer loop (t2 to next t1) */
- diff = time_to_us(time_sub(t1, last_t2));
+ outer_diff = time_to_us(time_sub(t1, last_t2));
/* This shouldn't happen */
- if (diff < 0) {
+ if (outer_diff < 0) {
pr_err(BANNER "time running backwards\n");
goto out;
}
- if (diff > outer_sample)
- outer_sample = diff;
+ if (outer_diff > outer_sample)
+ outer_sample = outer_diff;
}
last_t2 = t2;
@@ -216,6 +221,12 @@
/* This checks the inner loop (t1 to t2) */
diff = time_to_us(time_sub(t2, t1)); /* current diff */
+
+ if (diff > thresh || outer_diff > thresh) {
+ if (!count)
+ ktime_get_real_ts64(&s.timestamp);
+ count++;
+ }
/* This shouldn't happen */
if (diff < 0) {
@@ -236,7 +247,7 @@
/* If we exceed the threshold value, we have found a hardware latency */
if (sample > thresh || outer_sample > thresh) {
- struct hwlat_sample s;
+ u64 latency;
ret = 1;
@@ -248,16 +259,18 @@
s.seqnum = hwlat_data.count;
s.duration = sample;
s.outer_duration = outer_sample;
- ktime_get_real_ts64(&s.timestamp);
s.nmi_total_ts = nmi_total_ts;
s.nmi_count = nmi_count;
+ s.count = count;
trace_hwlat_sample(&s);
+ latency = max(sample, outer_sample);
+
/* Keep a running maximum ever recorded hardware latency */
- if (sample > tr->max_latency)
- tr->max_latency = sample;
- if (outer_sample > tr->max_latency)
- tr->max_latency = outer_sample;
+ if (latency > tr->max_latency) {
+ tr->max_latency = latency;
+ latency_fsnotify(tr);
+ }
}
out:
@@ -277,7 +290,7 @@
return;
/*
* If for some reason the user modifies the CPU affinity
- * of this thread, than stop migrating for the duration
+ * of this thread, then stop migrating for the duration
* of the current test.
*/
if (!cpumask_equal(current_mask, current->cpus_ptr))
@@ -359,7 +372,6 @@
return 0;
/* Just pick the first CPU on first iteration */
- current_mask = &save_cpumask;
get_online_cpus();
cpumask_and(current_mask, cpu_online_mask, tr->tracing_cpumask);
put_online_cpus();
@@ -526,14 +538,14 @@
*/
static int init_tracefs(void)
{
- struct dentry *d_tracer;
+ int ret;
struct dentry *top_dir;
- d_tracer = tracing_init_dentry();
- if (IS_ERR(d_tracer))
+ ret = tracing_init_dentry();
+ if (ret)
return -ENOMEM;
- top_dir = tracefs_create_dir("hwlat_detector", d_tracer);
+ top_dir = tracefs_create_dir("hwlat_detector", NULL);
if (!top_dir)
return -ENOMEM;
@@ -554,7 +566,7 @@
return 0;
err:
- tracefs_remove_recursive(top_dir);
+ tracefs_remove(top_dir);
return -ENOMEM;
}
--
Gitblit v1.6.2