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| author | Daniel Bristot de Oliveira <bristot@redhat.com> | 2016-07-01 20:44:37 -0300 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2016-07-15 15:52:41 -0400 |
| commit | 78aebca2c955c1c5aeb48e12645e13fe3c3461f2 (patch) | |
| tree | 65c65d6b60aeb0f4f50b1b811af4c32a894580e3 /include/trace/events/printk.h | |
| parent | 752d596b394c62f081393bbf53dff2a2c244632e (diff) | |
| download | linux-78aebca2c955c1c5aeb48e12645e13fe3c3461f2.tar.bz2 | |
printk, tracing: Avoiding unneeded blank lines
Printk messages often finish with '\n' to cause a new line.
But as each tracepoint is already printed in a new line,
printk messages that finish with '\n' ends up adding a blank
line to the trace output. For example:
kworker/0:1-86 [000] d... 46.006949: console: [ 46.006946] usb 1-3: USB disconnect, device number 3
kworker/2:2-374 [002] d... 48.699342: console: [ 48.699339] usb 1-3: new high-speed USB device number 4 using ehci-pci
kworker/2:2-374 [002] d... 49.041450: console: [ 49.041448] usb 1-3: New USB device found, idVendor=5986, idProduct=0
To avoid unneeded blank lines, this patch checks if the printk
message finishes with '\n', if so, it cut is off the '\n' to
avoid blank lines.
In a patched kernel, the same messages are printed without
extra blank lines. For example:
kworker/0:4-185 [000] d... 23.641738: console: [ 23.641736] usb 1-3: USB disconnect, device number 3
kworker/0:4-185 [000] d... 24.918703: console: [ 24.918700] usb 1-3: new high-speed USB device number 4 using ehci-pci
kworker/0:4-185 [000] d... 25.228308: console: [ 25.228306] usb 1-3: New USB device found, idVendor=5986, idProduct=02d5
Link: http://lkml.kernel.org/r/c350fb2521baaf681a1b4d67981ca0e900108e8e.1467407618.git.bristot@redhat.com
Cc: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: Anna Schumaker <anna.schumaker@netapp.com>
Cc: Ingo Molnar <mingo@redhat.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'include/trace/events/printk.h')
| -rw-r--r-- | include/trace/events/printk.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/include/trace/events/printk.h b/include/trace/events/printk.h index 542a7558154a..f350170059c6 100644 --- a/include/trace/events/printk.h +++ b/include/trace/events/printk.h @@ -16,6 +16,14 @@ TRACE_EVENT(console, ), TP_fast_assign( + /* + * Each trace entry is printed in a new line. + * If the msg finishes with '\n', cut it off + * to avoid blank lines in the trace. + */ + if ((len > 0) && (text[len-1] == '\n')) + len -= 1; + memcpy(__get_str(msg), text, len); __get_str(msg)[len] = 0; ), |