Merge pull request iovisor#372 from mcaleavya/master

migrated biosnoop and bashreadline to use bpf_perf_event_output

man/man8/bashreadline.8

@@ -10,6 +10,10 @@ entered command may fail: this is just showing what was entered.
 
 This program is also a basic example of eBPF/bcc and uprobes.
 
+This makes use of a Linux 4.5 feature (bpf_perf_event_output()); 
+for kernels older than 4.5, see the version under tools/old,
+which uses an older mechanism
+
 Since this uses BPF, only the root user can use this tool.
 .SH REQUIREMENTS
 CONFIG_BPF and bcc.

man/man8/biosnoop.8

@@ -15,6 +15,10 @@ request, as well as a starting timestamp for calculating I/O latency.
 This works by tracing various kernel blk_*() functions using dynamic tracing,
 and will need updating to match any changes to these functions.
 
+This makes use of a Linux 4.5 feature (bpf_perf_event_output());
+for kernels older than 4.5, see the version under tools/old,
+which uses an older mechanism
+
 Since this uses BPF, only the root user can use this tool.
 .SH REQUIREMENTS
 CONFIG_BPF and bcc.

tools/bashreadline.py

@@ -9,35 +9,55 @@
 # Licensed under the Apache License, Version 2.0 (the "License")
 #
 # 28-Jan-2016 Brendan Gregg Created this.
+# 12-Feb-2016 Allan McAleavy migrated to BPF_PERF_OUTPUT
 
 from __future__ import print_function
 from bcc import BPF
 from time import strftime
+import ctypes as ct
 
 # load BPF program
 bpf_text = """
 #include <uapi/linux/ptrace.h>
+
+struct str_t {
+ u64 pid;
+ char str[80];
+};
+
+BPF_PERF_OUTPUT(events);
+
 int printret(struct pt_regs *ctx) {
+ struct str_t data = {};
+ u32 pid;
  if (!ctx->ax)
  return 0;
-
- char str[80] = {};
- bpf_probe_read(&str, sizeof(str), (void *)ctx->ax);
- bpf_trace_printk("%s\\n", &str);
+ pid = bpf_get_current_pid_tgid();
+ data.pid = pid;
+ bpf_probe_read(&data.str, sizeof(data.str), (void *)ctx->ax);
+ events.perf_submit(ctx,&data,sizeof(data));
 
  return 0;
 };
 """
+STR_DATA = 80
+
+class Data(ct.Structure):
+ _fields_ = [
+ ("pid", ct.c_ulonglong),
+ ("str", ct.c_char * STR_DATA)
+ ]
+
 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
+def print_event(cpu, data, size):
+ event = ct.cast(data, ct.POINTER(Data)).contents
+ print("%-9s %-6d %s" % (strftime("%H:%M:%S"), event.pid, event.str))
+
+b["events"].open_perf_buffer(print_event)
 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))
+ b.kprobe_poll()

tools/biosnoop.py

@@ -11,9 +11,12 @@
 # Licensed under the Apache License, Version 2.0 (the "License")
 #
 # 16-Sep-2015 Brendan Gregg Created this.
+# 11-Feb-2016 Allan McAleavy updated for BPF_PERF_OUTPUT
 
 from __future__ import print_function
 from bcc import BPF
+import ctypes as ct
+import re
 
 # load BPF program
 b = BPF(text="""
@@ -25,8 +28,20 @@
  char name[TASK_COMM_LEN];
 };
 
+struct data_t {
+ u32 pid;
+ u64 rwflag;
+ u64 delta;
+ u64 sector;
+ u64 len;
+ u64 ts;
+ char disk_name[DISK_NAME_LEN];
+ char name[TASK_COMM_LEN];
+};
+
 BPF_HASH(start, struct request *);
 BPF_HASH(infobyreq, struct request *, struct val_t);
+BPF_PERF_OUTPUT(events);
 
 // cache PID and comm by-req
 int trace_pid_start(struct pt_regs *ctx, struct request *req)
@@ -37,7 +52,6 @@
  val.pid = bpf_get_current_pid_tgid();
  infobyreq.update(&req, &val);
  }
-
  return 0;
 }
 
@@ -58,37 +72,38 @@
  u64 *tsp, delta;
  u32 *pidp = 0;
  struct val_t *valp;
+ struct data_t data ={};
+ u64 ts;
 
  // fetch timestamp and calculate delta
  tsp = start.lookup(&req);
  if (tsp == 0) {
  // missed tracing issue
  return 0;
  }
- delta = bpf_ktime_get_ns() - *tsp;
+ ts = bpf_ktime_get_ns();
+ data.delta = ts - *tsp;
+ data.ts = ts / 1000;
 
- //
- // 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);
+ data.len = req->__data_len;
+ strcpy(data.name,"?");
  } else {
- bpf_trace_printk("0 %d %s %d\\n", valp->pid, valp->name,
- req->__data_len);
+ data.pid = valp->pid;
+ data.len = req->__data_len;
+ data.sector = req->__sector;
+ bpf_probe_read(&data.name, sizeof(data.name), valp->name);
+ bpf_probe_read(&data.disk_name, sizeof(data.disk_name),
+ req->rq_disk->disk_name);
  }
 
- // 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);
+ data.rwflag=1;
  } else {
- bpf_trace_printk("1 R %s %d %d ?\\n", req->rq_disk->disk_name,
- req->__sector, delta / 1000);
+ data.rwflag=0;
  }
-
+ events.perf_submit(ctx,&data,sizeof(data));
  start.delete(&req);
  infobyreq.delete(&req);
 
@@ -101,29 +116,61 @@
 b.attach_kprobe(event="blk_account_io_completion",
  fn_name="trace_req_completion")
 
+TASK_COMM_LEN = 16 # linux/sched.h
+DISK_NAME_LEN = 32 # linux/genhd.h
+
+class Data(ct.Structure):
+ _fields_ = [
+ ("pid", ct.c_ulonglong),
+ ("rwflag", ct.c_ulonglong),
+ ("delta", ct.c_ulonglong),
+ ("sector", ct.c_ulonglong),
+ ("len", ct.c_ulonglong),
+ ("ts", ct.c_ulonglong),
+ ("disk_name", ct.c_char * DISK_NAME_LEN),
+ ("name", ct.c_char * TASK_COMM_LEN)
+ ]
 # header
 print("%-14s %-14s %-6s %-7s %-2s %-9s %-7s %7s" % ("TIME(s)", "COMM", "PID",
  "DISK", "T", "SECTOR", "BYTES", "LAT(ms)"))
 
+rwflg = ""
 start_ts = 0
+prev_ts = 0
+delta = 0
 
-# format output
-while 1:
- (task, pid, cpu, flags, ts, msg) = b.trace_fields()
- args = msg.split(" ")
+# process event
+def print_event(cpu, data, size):
+ event = ct.cast(data, ct.POINTER(Data)).contents
 
- if start_ts == 0:
- start_ts = ts
+ val = -1
+ global start_ts
+ global prev_ts
+ global delta
+
+ if event.rwflag == 1:
+ rwflg = "W"
+
+ if event.rwflag == 0:
+ rwflg = "R"
+
+ if not re.match('\?', event.name):
+ val = event.sector
 
- 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])
+ if start_ts == 0:
+ prev_ts = start_ts
 
- ms = float(int(us_s, 10)) / 1000
+ if start_ts == 1:
+ delta = float(delta) + (event.ts - prev_ts)
 
  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))
+ delta / 1000000, event.name, event.pid, event.disk_name, rwflg, val,
+ event.len, float(event.delta) / 1000000))
+
+ prev_ts = event.ts
+ start_ts = 1
+
+# loop with callback to print_event
+b["events"].open_perf_buffer(print_event)
+while 1:
+ b.kprobe_poll()

tools/old/bashreadline.py

@@ -0,0 +1,43 @@
+#!/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))