reworking of biosnoop and bashreadline to use bf_perf_event_output. Also moved...

reworking of biosnoop and bashreadline to use bf_perf_event_output. Also moved old versions to tools/old

tools/old/bashreadline.py

+#!/usr/bin/python
+#
+# bashreadline  Print entered bash commands from all running shells.
+#               For Linux, uses BCC, eBPF. Embedded C.
+#
+# This works by tracing the readline() function using a uretprobe (uprobes).
+#
+# Copyright 2016 Netflix, Inc.
+# Licensed under the Apache License, Version 2.0 (the "License")
+#
+# 28-Jan-2016    Brendan Gregg   Created this.
+
+from __future__ import print_function
+from bcc import BPF
+from time import strftime
+
+# load BPF program
+bpf_text = """
+#include <uapi/linux/ptrace.h>
+int printret(struct pt_regs *ctx) {
+    if (!ctx->ax)
+        return 0;
+
+    char str[80] = {};
+    bpf_probe_read(&str, sizeof(str), (void *)ctx->ax);
+    bpf_trace_printk("%s\\n", &str);
+
+    return 0;
+};
+"""
+b = BPF(text=bpf_text)
+b.attach_uretprobe(name="/bin/bash", sym="readline", fn_name="printret")
+
+# header
+print("%-9s %-6s %s" % ("TIME", "PID", "COMMAND"))
+
+# format output
+while 1:
+    try:
+        (task, pid, cpu, flags, ts, msg) = b.trace_fields()
+    except ValueError:
+        continue
+    print("%-9s %-6d %s" % (strftime("%H:%M:%S"), pid, msg))

tools/old/biosnoop.py

+#!/usr/bin/python
+# @lint-avoid-python-3-compatibility-imports
+#
+# biosnoop  Trace block device I/O and print details including issuing PID.
+#       For Linux, uses BCC, eBPF.
+#
+# This uses in-kernel eBPF maps to cache process details (PID and comm) by I/O
+# request, as well as a starting timestamp for calculating I/O latency.
+#
+# Copyright (c) 2015 Brendan Gregg.
+# Licensed under the Apache License, Version 2.0 (the "License")
+#
+# 16-Sep-2015   Brendan Gregg   Created this.
+
+from __future__ import print_function
+from bcc import BPF
+
+# load BPF program
+b = BPF(text="""
+#include <uapi/linux/ptrace.h>
+#include <linux/blkdev.h>
+
+struct val_t {
+    u32 pid;
+    char name[TASK_COMM_LEN];
+};
+
+BPF_HASH(start, struct request *);
+BPF_HASH(infobyreq, struct request *, struct val_t);
+
+// cache PID and comm by-req
+int trace_pid_start(struct pt_regs *ctx, struct request *req)
+{
+    struct val_t val = {};
+
+    if (bpf_get_current_comm(&val.name, sizeof(val.name)) == 0) {
+        val.pid = bpf_get_current_pid_tgid();
+        infobyreq.update(&req, &val);
+    }
+
+    return 0;
+}
+
+// time block I/O
+int trace_req_start(struct pt_regs *ctx, struct request *req)
+{
+    u64 ts;
+
+    ts = bpf_ktime_get_ns();
+    start.update(&req, &ts);
+
+    return 0;
+}
+
+// output
+int trace_req_completion(struct pt_regs *ctx, struct request *req)
+{
+    u64 *tsp, delta;
+    u32 *pidp = 0;
+    struct val_t *valp;
+
+    // fetch timestamp and calculate delta
+    tsp = start.lookup(&req);
+    if (tsp == 0) {
+        // missed tracing issue
+        return 0;
+    }
+    delta = bpf_ktime_get_ns() - *tsp;
+
+    //
+    // Fetch and output issuing pid and comm.
+    // As bpf_trace_prink() is limited to a maximum of 1 string and 2
+    // integers, we'll use more than one to output the data.
+    //
+    valp = infobyreq.lookup(&req);
+    if (valp == 0) {
+        bpf_trace_printk("0 0 ? %d\\n", req->__data_len);
+    } else {
+        bpf_trace_printk("0 %d %s %d\\n", valp->pid, valp->name,
+            req->__data_len);
+    }
+
+    // output remaining details
+    if (req->cmd_flags & REQ_WRITE) {
+        bpf_trace_printk("1 W %s %d %d ?\\n", req->rq_disk->disk_name,
+            req->__sector, delta / 1000);
+    } else {
+        bpf_trace_printk("1 R %s %d %d ?\\n", req->rq_disk->disk_name,
+            req->__sector, delta / 1000);
+    }
+
+    start.delete(&req);
+    infobyreq.delete(&req);
+
+    return 0;
+}
+""", debug=0)
+b.attach_kprobe(event="blk_account_io_start", fn_name="trace_pid_start")
+b.attach_kprobe(event="blk_start_request", fn_name="trace_req_start")
+b.attach_kprobe(event="blk_mq_start_request", fn_name="trace_req_start")
+b.attach_kprobe(event="blk_account_io_completion",
+    fn_name="trace_req_completion")
+
+# header
+print("%-14s %-14s %-6s %-7s %-2s %-9s %-7s %7s" % ("TIME(s)", "COMM", "PID",
+    "DISK", "T", "SECTOR", "BYTES", "LAT(ms)"))
+
+start_ts = 0
+
+# format output
+while 1:
+    (task, pid, cpu, flags, ts, msg) = b.trace_fields()
+    args = msg.split(" ")
+
+    if start_ts == 0:
+        start_ts = ts
+
+    if args[0] == "0":
+        (real_pid, real_comm, bytes_s) = (args[1], args[2], args[3])
+        continue
+    else:
+        (type_s, disk_s, sector_s, us_s) = (args[1], args[2], args[3],
+            args[4])
+
+    ms = float(int(us_s, 10)) / 1000
+
+    print("%-14.9f %-14.14s %-6s %-7s %-2s %-9s %-7s %7.2f" % (
+        ts - start_ts, real_comm, real_pid, disk_s, type_s, sector_s,
+        bytes_s, ms))