Merge pull request #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 @@ struct val_t {
     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 @@ int trace_pid_start(struct pt_regs *ctx, struct request *req)
         val.pid = bpf_get_current_pid_tgid();
         infobyreq.update(&req, &val);
     }
-
     return 0;
 }
 
@@ -58,6 +72,8 @@ int trace_req_completion(struct pt_regs *ctx, struct request *req)
     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);
@@ -65,30 +81,29 @@ int trace_req_completion(struct pt_regs *ctx, struct request *req)
         // 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_mq_start_request", fn_name="trace_req_start")
 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

+#!/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))