examples/tracing: Use printb to improve python3 compatibility

When using python3, 'print' will output the bytes arrays with the "b"
prefix. Switch to printb to get rid of the prefix.

Signed-off-by: Gary Lin <glin@suse.com>
diff --git a/examples/tracing/disksnoop.py b/examples/tracing/disksnoop.py
index 17d911a..e181235 100755
--- a/examples/tracing/disksnoop.py
+++ b/examples/tracing/disksnoop.py
@@ -12,6 +12,7 @@
 
 from __future__ import print_function
 from bcc import BPF
+from bcc.utils import printb
 
 REQ_WRITE = 1		# from include/linux/blk_types.h
 
@@ -56,13 +57,13 @@
 		(bytes_s, bflags_s, us_s) = msg.split()
 
 		if int(bflags_s, 16) & REQ_WRITE:
-			type_s = "W"
+			type_s = b"W"
 		elif bytes_s == "0":	# see blk_fill_rwbs() for logic
-			type_s = "M"
+			type_s = b"M"
 		else:
-			type_s = "R"
+			type_s = b"R"
 		ms = float(int(us_s, 10)) / 1000
 
-		print("%-18.9f %-2s %-7s %8.2f" % (ts, type_s, bytes_s, ms))
+		printb(b"%-18.9f %-2s %-7s %8.2f" % (ts, type_s, bytes_s, ms))
 	except KeyboardInterrupt:
 		exit()
diff --git a/examples/tracing/hello_fields.py b/examples/tracing/hello_fields.py
index be53e62..b8ee6db 100755
--- a/examples/tracing/hello_fields.py
+++ b/examples/tracing/hello_fields.py
@@ -3,6 +3,7 @@
 # This is a Hello World example that formats output as fields.
 
 from bcc import BPF
+from bcc.utils import printb
 
 # define BPF program
 prog = """
@@ -25,4 +26,4 @@
         (task, pid, cpu, flags, ts, msg) = b.trace_fields()
     except ValueError:
         continue
-    print("%-18.9f %-16s %-6d %s" % (ts, task, pid, msg))
+    printb(b"%-18.9f %-16s %-6d %s" % (ts, task, pid, msg))
diff --git a/examples/tracing/hello_perf_output.py b/examples/tracing/hello_perf_output.py
index bcf8b43..fdc74de 100755
--- a/examples/tracing/hello_perf_output.py
+++ b/examples/tracing/hello_perf_output.py
@@ -3,6 +3,7 @@
 # This is a Hello World example that uses BPF_PERF_OUTPUT.
 
 from bcc import BPF
+from bcc.utils import printb
 
 # define BPF program
 prog = """
@@ -44,8 +45,8 @@
     if start == 0:
             start = event.ts
     time_s = (float(event.ts - start)) / 1000000000
-    print("%-18.9f %-16s %-6d %s" % (time_s, event.comm, event.pid,
-        "Hello, perf_output!"))
+    printb(b"%-18.9f %-16s %-6d %s" % (time_s, event.comm, event.pid,
+        b"Hello, perf_output!"))
 
 # loop with callback to print_event
 b["events"].open_perf_buffer(print_event)
diff --git a/examples/tracing/mallocstacks.py b/examples/tracing/mallocstacks.py
index 2f3eb25..84b435e1 100755
--- a/examples/tracing/mallocstacks.py
+++ b/examples/tracing/mallocstacks.py
@@ -12,6 +12,7 @@
 
 from __future__ import print_function
 from bcc import BPF
+from bcc.utils import printb
 from time import sleep
 import sys
 
@@ -56,4 +57,4 @@
 for k, v in reversed(sorted(calls.items(), key=lambda c: c[1].value)):
     print("%d bytes allocated at:" % v.value)
     for addr in stack_traces.walk(k.value):
-        print("\t%s" % b.sym(addr, pid, show_offset=True))
+        printb(b"\t%s" % b.sym(addr, pid, show_offset=True))
diff --git a/examples/tracing/mysqld_query.py b/examples/tracing/mysqld_query.py
index 15ff297..aa453ce 100755
--- a/examples/tracing/mysqld_query.py
+++ b/examples/tracing/mysqld_query.py
@@ -12,6 +12,7 @@
 
 from __future__ import print_function
 from bcc import BPF, USDT
+from bcc.utils import printb
 import sys
 
 if len(sys.argv) < 2:
@@ -58,4 +59,4 @@
     except ValueError:
         print("value error")
         continue
-    print("%-18.9f %-16s %-6d %s" % (ts, task, pid, msg))
+    printb(b"%-18.9f %-16s %-6d %s" % (ts, task, pid, msg))
diff --git a/examples/tracing/nodejs_http_server.py b/examples/tracing/nodejs_http_server.py
index 1017de5..1f6a7b9 100755
--- a/examples/tracing/nodejs_http_server.py
+++ b/examples/tracing/nodejs_http_server.py
@@ -10,6 +10,7 @@
 
 from __future__ import print_function
 from bcc import BPF, USDT
+from bcc.utils import printb
 import sys
 
 if len(sys.argv) < 2:
@@ -51,4 +52,4 @@
     except ValueError:
         print("value error")
         continue
-    print("%-18.9f %-16s %-6d %s" % (ts, task, pid, msg))
+    printb(b"%-18.9f %-16s %-6d %s" % (ts, task, pid, msg))
diff --git a/examples/tracing/strlen_count.py b/examples/tracing/strlen_count.py
index 49d7080..eab6710 100755
--- a/examples/tracing/strlen_count.py
+++ b/examples/tracing/strlen_count.py
@@ -12,6 +12,7 @@
 
 from __future__ import print_function
 from bcc import BPF
+from bcc.utils import printb
 from time import sleep
 
 # load BPF program
@@ -52,4 +53,4 @@
 print("%10s %s" % ("COUNT", "STRING"))
 counts = b.get_table("counts")
 for k, v in sorted(counts.items(), key=lambda counts: counts[1].value):
-    print("%10d \"%s\"" % (v.value, k.c.encode('string-escape')))
+    printb(b"%10d \"%s\"" % (v.value, k.c))
diff --git a/examples/tracing/sync_timing.py b/examples/tracing/sync_timing.py
index 675ad14..4fad777 100755
--- a/examples/tracing/sync_timing.py
+++ b/examples/tracing/sync_timing.py
@@ -10,6 +10,7 @@
 
 from __future__ import print_function
 from bcc import BPF
+from bcc.utils import printb
 
 # load BPF program
 b = BPF(text="""
@@ -48,4 +49,4 @@
     if start == 0:
         start = ts
     ts = ts - start
-    print("At time %.2f s: multiple syncs detected, last %s ms ago" % (ts, ms))
+    printb(b"At time %.2f s: multiple syncs detected, last %s ms ago" % (ts, ms))
diff --git a/examples/tracing/tcpv4connect.py b/examples/tracing/tcpv4connect.py
index 8a89469..81385e8 100755
--- a/examples/tracing/tcpv4connect.py
+++ b/examples/tracing/tcpv4connect.py
@@ -16,6 +16,7 @@
 
 from __future__ import print_function
 from bcc import BPF
+from bcc.utils import printb
 
 # define BPF program
 bpf_text = """
@@ -76,11 +77,11 @@
     "DPORT"))
 
 def inet_ntoa(addr):
-	dq = ''
+	dq = b''
 	for i in range(0, 4):
-		dq = dq + str(addr & 0xff)
+		dq = dq + str(addr & 0xff).encode()
 		if (i != 3):
-			dq = dq + '.'
+			dq = dq + b'.'
 		addr = addr >> 8
 	return dq
 
@@ -89,7 +90,7 @@
 	# Read messages from kernel pipe
 	try:
 	    (task, pid, cpu, flags, ts, msg) = b.trace_fields()
-	    (_tag, saddr_hs, daddr_hs, dport_s) = msg.split(" ")
+	    (_tag, saddr_hs, daddr_hs, dport_s) = msg.split(b" ")
 	except ValueError:
 	    # Ignore messages from other tracers
 	    continue
@@ -98,7 +99,7 @@
 	if _tag != "trace_tcp4connect":
 	    continue
 
-	print("%-6d %-12.12s %-16s %-16s %-4s" % (pid, task,
+	printb(b"%-6d %-12.12s %-16s %-16s %-4s" % (pid, task,
 	    inet_ntoa(int(saddr_hs, 16)),
 	    inet_ntoa(int(daddr_hs, 16)),
 	    dport_s))
diff --git a/examples/tracing/trace_perf_output.py b/examples/tracing/trace_perf_output.py
index 35a5795..635be12 100755
--- a/examples/tracing/trace_perf_output.py
+++ b/examples/tracing/trace_perf_output.py
@@ -8,6 +8,7 @@
 
 import atexit
 from bcc import BPF
+from bcc.utils import printb
 import ctypes as ct
 
 class Data(ct.Structure):
@@ -50,7 +51,7 @@
     global b
     print("counter = %d vs %d" % (counter, b["counters"][ct.c_int(0)].value))
 
-print("Tracing " + event_name + ", try `dd if=/dev/zero of=/dev/null`")
+printb(b"Tracing " + event_name + b", try `dd if=/dev/zero of=/dev/null`")
 print("Tracing... Hit Ctrl-C to end.")
 while 1:
     try:
diff --git a/examples/tracing/urandomread-explicit.py b/examples/tracing/urandomread-explicit.py
index 448ffdf..0706092 100755
--- a/examples/tracing/urandomread-explicit.py
+++ b/examples/tracing/urandomread-explicit.py
@@ -17,6 +17,7 @@
 
 from __future__ import print_function
 from bcc import BPF
+from bcc.utils import printb
 
 # define BPF program
 bpf_text = """
@@ -49,4 +50,4 @@
         (task, pid, cpu, flags, ts, msg) = b.trace_fields()
     except ValueError:
         continue
-    print("%-18.9f %-16s %-6d %s" % (ts, task, pid, msg))
+    printb(b"%-18.9f %-16s %-6d %s" % (ts, task, pid, msg))
diff --git a/examples/tracing/urandomread.py b/examples/tracing/urandomread.py
index 319db2c..c1468c8 100755
--- a/examples/tracing/urandomread.py
+++ b/examples/tracing/urandomread.py
@@ -13,6 +13,7 @@
 
 from __future__ import print_function
 from bcc import BPF
+from bcc.utils import printb
 
 # load BPF program
 b = BPF(text="""
@@ -32,4 +33,4 @@
         (task, pid, cpu, flags, ts, msg) = b.trace_fields()
     except ValueError:
         continue
-    print("%-18.9f %-16s %-6d %s" % (ts, task, pid, msg))
+    printb(b"%-18.9f %-16s %-6d %s" % (ts, task, pid, msg))