Moving duration to primary argument for tcpconnlat. Also updating docs for tcpconnlat to match.

man/man8/tcpconnlat.8

@@ -2,7 +2,7 @@
 .SH NAME
 tcpconnlat \- Trace TCP active connection latency. Uses Linux eBPF/bcc.
 .SH SYNOPSIS
-.B tcpconnlat [\-h] [\-t] [\-p PID] [-m MIN_MS] [-u MIN_US] [-v]
+.B tcpconnlat [\-h] [\-t] [\-p PID] [-v] [min_ms]
 .SH DESCRIPTION
 This tool traces active TCP connections
 (eg, via a connect() syscall), and shows the latency (time) for the connection
@@ -31,14 +31,11 @@ Include a timestamp column.
 \-p PID
 Trace this process ID only (filtered in-kernel).
 .TP
-\-m MIN_NS
-Minimum duration to trace, in milliseconds.
-.TP
-\-u MIN_US
-Minimum duration to trace, in microseconds.
-.TP
 \-v
 Print the resulting BPF program, for debugging purposes.
+.TP
+min_ns
+Minimum duration to trace, in milliseconds.
 .SH EXAMPLES
 .TP
 Trace all active TCP connections, and show connection latency (SYN->response round trip):
@@ -55,7 +52,7 @@ Trace PID 181 only:
 .TP
 Trace connects with latency longer than 10 ms:
 #
-.B tcpconnlat \-m 10
+.B tcpconnlat 10
 .TP
 Print the BPF program:
 #

tools/tcpconnlat.py

@@ -21,11 +21,22 @@ from struct import pack
 import argparse
 import ctypes as ct
 
+# arg validation
+def positive_float(val):
+    try:
+        ival = float(val)
+    except ValueError:
+        raise argparse.ArgumentTypeError("must be a float")
+
+    if ival < 0:
+        raise argparse.ArgumentTypeError("must be positive")
+    return ival
+
 # arguments
 examples = """examples:
     ./tcpconnlat           # trace all TCP connect()s
-    ./tcpconnlat -m 1      # only show results slower than 1 ms
-    ./tcpconnlat -u 100    # only show results slower than 100 microseconds
+    ./tcpconnlat 1         # trace connection latency slower than 1 ms
+    ./tcpconnlat 0.1       # trace connection latency slower than 100 us
     ./tcpconnlat -t        # include timestamps
     ./tcpconnlat -p 181    # only trace PID 181
 """
@@ -37,18 +48,16 @@ parser.add_argument("-t", "--timestamp", action="store_true",
     help="include timestamp on output")
 parser.add_argument("-p", "--pid",
     help="trace this PID only")
-parser.add_argument("-m", "--min-ms", type=float, dest="min_ms",
-    help="minimum latency filter (ms)")
-parser.add_argument("-u", "--min-us", type=float, dest="min_us",
-    help="minimum latency filter (us)")
+parser.add_argument("duration_ms", nargs="?", default=0,
+    type=positive_float,
+    help="minimum duration to trace (ms)")
 parser.add_argument("-v", "--verbose", action="store_true",
     help="print the BPF program for debugging purposes")
 args = parser.parse_args()
 
-if args.min_ms:
-    duration_us = int(args.min_ms * 1000)
-elif args.min_us:
-    duration_us = int(args.min_us)
+if args.duration_ms:
+    # support fractions but round to nearest microsecond
+    duration_us = int(args.duration_ms * 1000)
 else:
     duration_us = 0   # default is show all
 

tools/tcpconnlat_example.txt

@@ -47,6 +47,6 @@ examples:
     ./tcpconnlat           # trace all TCP connect()s
     ./tcpconnlat -t        # include timestamps
     ./tcpconnlat -p 181    # only trace PID 181
-    ./tcpconnlat -m 1      # only show connects longer than 1 ms
-    ./tcpconnlat -u 100    # only show connects longer than 100 us
+    ./tcpconnlat 1         # only show connects longer than 1 ms
+    ./tcpconnlat 0.1       # only show connects longer than 100 us
     ./tcpconnlat -v        # Show the BPF program