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Subject[RFC v2 15/17] perf kwork: Add irq trace bpf support
Date
Implements irq trace bpf function.

Test cases:
Trace irq without filter:

# perf kwork -k irq rep -b
Starting trace, Hit <Ctrl+C> to stop and report
^C
Kwork Name | Cpu | Total Runtime | Count | Max runtime | Max runtime start | Max runtime end |
--------------------------------------------------------------------------------------------------------------------------------
virtio0-requests:25 | 0000 | 31.026 ms | 285 | 1.493 ms | 110326.049963 s | 110326.051456 s |
eth0:10 | 0002 | 7.875 ms | 96 | 1.429 ms | 110313.916835 s | 110313.918264 s |
ata_piix:14 | 0002 | 2.510 ms | 28 | 0.396 ms | 110331.367987 s | 110331.368383 s |
--------------------------------------------------------------------------------------------------------------------------------

Trace irq with cpu filter:

# perf kwork -k irq rep -b -C 0
Starting trace, Hit <Ctrl+C> to stop and report
^C
Kwork Name | Cpu | Total Runtime | Count | Max runtime | Max runtime start | Max runtime end |
--------------------------------------------------------------------------------------------------------------------------------
virtio0-requests:25 | 0000 | 34.288 ms | 282 | 2.061 ms | 110358.078968 s | 110358.081029 s |
--------------------------------------------------------------------------------------------------------------------------------

Trace irq with name filter:

# perf kwork -k irq rep -b -n eth0
Starting trace, Hit <Ctrl+C> to stop and report
^C
Kwork Name | Cpu | Total Runtime | Count | Max runtime | Max runtime start | Max runtime end |
--------------------------------------------------------------------------------------------------------------------------------
eth0:10 | 0002 | 2.184 ms | 21 | 0.572 ms | 110386.541699 s | 110386.542271 s |
--------------------------------------------------------------------------------------------------------------------------------

Trace irq with summary:

# perf kwork -k irq rep -b -S
Starting trace, Hit <Ctrl+C> to stop and report
^C
Kwork Name | Cpu | Total Runtime | Count | Max runtime | Max runtime start | Max runtime end |
--------------------------------------------------------------------------------------------------------------------------------
virtio0-requests:25 | 0000 | 42.923 ms | 285 | 1.181 ms | 110418.128867 s | 110418.130049 s |
eth0:10 | 0002 | 2.085 ms | 20 | 0.668 ms | 110416.002935 s | 110416.003603 s |
ata_piix:14 | 0002 | 0.970 ms | 4 | 0.656 ms | 110424.034482 s | 110424.035138 s |
--------------------------------------------------------------------------------------------------------------------------------
Total count : 309
Total runtime (msec) : 45.977 (0.003% load average)
Total time span (msec) : 17017.655
--------------------------------------------------------------------------------------------------------------------------------

Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
---
tools/perf/util/bpf_kwork.c | 40 +++++-
tools/perf/util/bpf_skel/kwork_trace.bpf.c | 150 +++++++++++++++++++++
2 files changed, 189 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/bpf_kwork.c b/tools/perf/util/bpf_kwork.c
index 433bfadd3af1..08252fcda1a4 100644
--- a/tools/perf/util/bpf_kwork.c
+++ b/tools/perf/util/bpf_kwork.c
@@ -62,9 +62,47 @@ void perf_kwork__trace_finish(void)
skel->bss->enabled = 0;
}

+static int get_work_name_from_map(struct work_key *key, char **ret_name)
+{
+ char name[MAX_KWORKNAME] = { 0 };
+ int fd = bpf_map__fd(skel->maps.perf_kwork_names);
+
+ *ret_name = NULL;
+
+ if (fd < 0) {
+ pr_debug("Invalid names map fd\n");
+ return 0;
+ }
+
+ if ((bpf_map_lookup_elem(fd, key, name) == 0) && (strlen(name) != 0)) {
+ *ret_name = strdup(name);
+ if (*ret_name == NULL) {
+ pr_err("Failed to copy work name\n");
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+static void irq_load_prepare(struct perf_kwork *kwork)
+{
+ if (kwork->report == KWORK_REPORT_RUNTIME) {
+ bpf_program__set_autoload(
+ skel->progs.report_irq_handler_entry, true);
+ bpf_program__set_autoload(
+ skel->progs.report_irq_handler_exit, true);
+ }
+}
+
+static struct kwork_class_bpf kwork_irq_bpf = {
+ .load_prepare = irq_load_prepare,
+ .get_work_name = get_work_name_from_map,
+};
+
static struct kwork_class_bpf *
kwork_class_bpf_supported_list[KWORK_CLASS_MAX] = {
- [KWORK_CLASS_IRQ] = NULL,
+ [KWORK_CLASS_IRQ] = &kwork_irq_bpf,
[KWORK_CLASS_SOFTIRQ] = NULL,
[KWORK_CLASS_WORKQUEUE] = NULL,
};
diff --git a/tools/perf/util/bpf_skel/kwork_trace.bpf.c b/tools/perf/util/bpf_skel/kwork_trace.bpf.c
index 36112be831e3..1925407d1c16 100644
--- a/tools/perf/util/bpf_skel/kwork_trace.bpf.c
+++ b/tools/perf/util/bpf_skel/kwork_trace.bpf.c
@@ -71,4 +71,154 @@ int enabled = 0;
int has_cpu_filter = 0;
int has_name_filter = 0;

+static __always_inline int local_strncmp(const char *s1,
+ unsigned int sz, const char *s2)
+{
+ int ret = 0;
+ unsigned int i;
+
+ for (i = 0; i < sz; i++) {
+ ret = (unsigned char)s1[i] - (unsigned char)s2[i];
+ if (ret || !s1[i] || !s2[i])
+ break;
+ }
+
+ return ret;
+}
+
+static __always_inline int trace_event_match(struct work_key *key, char *name)
+{
+ __u8 *cpu_val;
+ char *name_val;
+ __u32 zero = 0;
+ __u32 cpu = bpf_get_smp_processor_id();
+
+ if (!enabled)
+ return 0;
+
+ if (has_cpu_filter) {
+ cpu_val = bpf_map_lookup_elem(&perf_kwork_cpu_filter, &cpu);
+ if (!cpu_val)
+ return 0;
+ }
+
+ if (has_name_filter && (name != NULL)) {
+ name_val = bpf_map_lookup_elem(&perf_kwork_name_filter, &zero);
+ if (name_val &&
+ (local_strncmp(name_val, MAX_KWORKNAME, name) != 0)) {
+ return 0;
+ }
+ }
+
+ return 1;
+}
+
+static __always_inline void do_update_time(void *map, struct work_key *key,
+ __u64 time_start, __u64 time_end)
+{
+ struct report_data zero, *data;
+ __s64 delta = time_end - time_start;
+
+ if (delta < 0)
+ return;
+
+ data = bpf_map_lookup_elem(map, key);
+ if (!data) {
+ __builtin_memset(&zero, 0, sizeof(zero));
+ bpf_map_update_elem(map, key, &zero, BPF_NOEXIST);
+ data = bpf_map_lookup_elem(map, key);
+ if (!data)
+ return;
+ }
+
+ if ((delta > data->max_time) ||
+ (data->max_time == 0)) {
+ data->max_time = delta;
+ data->max_time_start = time_start;
+ data->max_time_end = time_end;
+ }
+
+ data->total_time += delta;
+ data->nr++;
+}
+
+static __always_inline void do_update_timestart(void *map, struct work_key *key)
+{
+ __u64 ts = bpf_ktime_get_ns();
+
+ bpf_map_update_elem(map, key, &ts, BPF_ANY);
+}
+
+static __always_inline void do_update_timeend(void *report_map, void *time_map,
+ struct work_key *key)
+{
+ __u64 *time = bpf_map_lookup_elem(time_map, key);
+
+ if (time) {
+ bpf_map_delete_elem(time_map, key);
+ do_update_time(report_map, key, *time, bpf_ktime_get_ns());
+ }
+}
+
+static __always_inline void do_update_name(void *map,
+ struct work_key *key, char *name)
+{
+ if (!bpf_map_lookup_elem(map, key))
+ bpf_map_update_elem(map, key, name, BPF_ANY);
+}
+
+static __always_inline int update_timestart_and_name(void *time_map,
+ void *names_map,
+ struct work_key *key,
+ char *name)
+{
+ if (!trace_event_match(key, name))
+ return 0;
+
+ do_update_timestart(time_map, key);
+ do_update_name(names_map, key, name);
+
+ return 0;
+}
+
+static __always_inline int update_timeend(void *report_map,
+ void *time_map, struct work_key *key)
+{
+ if (!trace_event_match(key, NULL))
+ return 0;
+
+ do_update_timeend(report_map, time_map, key);
+
+ return 0;
+}
+
+SEC("tracepoint/irq/irq_handler_entry")
+int report_irq_handler_entry(struct trace_event_raw_irq_handler_entry *ctx)
+{
+ char name[MAX_KWORKNAME];
+ struct work_key key = {
+ .type = KWORK_CLASS_IRQ,
+ .cpu = bpf_get_smp_processor_id(),
+ .id = (__u64)ctx->irq,
+ };
+ void *name_addr = (void *)ctx + (ctx->__data_loc_name & 0xffff);
+
+ bpf_probe_read_kernel_str(name, sizeof(name), name_addr);
+
+ return update_timestart_and_name(&perf_kwork_time,
+ &perf_kwork_names, &key, name);
+}
+
+SEC("tracepoint/irq/irq_handler_exit")
+int report_irq_handler_exit(struct trace_event_raw_irq_handler_exit *ctx)
+{
+ struct work_key key = {
+ .type = KWORK_CLASS_IRQ,
+ .cpu = bpf_get_smp_processor_id(),
+ .id = (__u64)ctx->irq,
+ };
+
+ return update_timeend(&perf_kwork_report, &perf_kwork_time, &key);
+}
+
char LICENSE[] SEC("license") = "Dual BSD/GPL";
--
2.30.GIT
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