bcc/tools: Trace virtqueue kick event for virtio driver.

tools/vqkick.py

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+#!/usr/bin/env python3
+#
+# vqkick.py
+#
+# Trace virtqueue kick event for virtio driver.
+# $./vqkick.py
+# TIME               CPU  VQ_NAME
+# 327344.930087496   5    b'output.0'
+# 327344.930896929   5    b'output.0'
+# 327344.930993290   5    b'output.0'
+# 327344.931079160   5    b'output.0'
+# 327344.931161010   5    b'output.0'
+# 327344.931231561   5    b'output.0'
+
+# @TIME: Timestamp for virtqueue kick event.
+# @CPU: Which cpu occur virtqueue kick event.
+# @VQ_NAME: Name of virtqueue.
+#
+# Copyright (c) 2023 kylinos Inc. All rights reserved.
+#
+# Author(s):
+#   Longjun Tang <tanglongjun@kylinos.cn>
+
+
+import sys
+from bcc import BPF
+import argparse
+
+
+# define BPF program
+bpf_text = '''
+#include <uapi/linux/ptrace.h>
+#include <linux/virtio.h>
+
+typedef struct event_log {
+	u64 ts;
+	u32 cpu;
+	char vq_name[32];
+} event_log_t;
+
+
+BPF_PERF_OUTPUT(vq_kick_event);
+
+int kprobe__virtqueue_notify(struct pt_regs *ctx, struct virtqueue *vq)
+{
+	event_log_t vq_kick_event_log = {};
+
+	vq_kick_event_log.cpu = bpf_get_smp_processor_id();
+	vq_kick_event_log.ts = bpf_ktime_get_ns();
+	char *name = (char *)vq->name;
+	bpf_probe_read_kernel(&vq_kick_event_log.vq_name, sizeof(vq_kick_event_log.vq_name), name);
+
+	vq_kick_event.perf_submit(ctx, &vq_kick_event_log, sizeof(vq_kick_event_log));
+
+	return 0;
+}
+'''
+
+def print_vq_kick_event_log(cpu, data, size):
+	event = b["vq_kick_event"].event(data)
+	time_s = float(event.ts) / 1000000000
+	print("%-18.9f %-4d %-16s" % (time_s, event.cpu, event.vq_name))
+
+
+if __name__ == "__main__":
+    b = BPF(text=bpf_text)
+    b["vq_kick_event"].open_perf_buffer(print_vq_kick_event_log)
+
+    # header
+    print("\n%-18s %-4s %-32s" % ("TIME", "CPU", "VQ_NAME"))
+
+    try:
+        while True:
+	        b.kprobe_poll(1)
+    except KeyboardInterrupt:
+        pass

tools/vqkick_example.txt

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+Demonstrations of vqkick.py.
+
+
+Trace virtqueue kick event for virtio driver.
+
+For example:
+
+# $./vqkick.py
+# TIME               CPU  VQ_NAME
+# 327344.930087496   5    b'output.0'
+# 327344.930896929   5    b'output.0'
+# 327344.930993290   5    b'output.0'
+# 327344.931079160   5    b'output.0'
+# 327344.931161010   5    b'output.0'
+# 327344.931231561   5    b'output.0'
+
+@TIME: Timestamp for virtqueue kick event.
+@CPU: Which cpu occur virtqueue kick event.
+@VQ_NAME: Name of virtqueue.
+
+examples:
+    ./vqkick.py                              # Trace virtqueue kick event for virtio driver until Ctrl-C