Re: How to disable tracing at runtime from the Linux kernel command line?

[Steven Rostedt]

On Sat, 14 Apr 2018 15:09:33 +0200
Paul Menzel  wrote:

> Dear Linux folks,
> 
> 
> I am trying to reduce the boot time of a standard Linux distribution 
> kernel. Currently, distributions – at least Debian und Ubuntu – enable 
> function tracing.
> 
> ```
> CONFIG_FTRACE=y
> CONFIG_FUNCTION_TRACER=y
> CONFIG_FUNCTION_GRAPH_TRACER=y
> 
> CONFIG_EVENT_TRACING=y
> ```
> 
> This is great, as it makes it easy to use tracing to hunt down things 
> holding up the boot. But it also skews the boot time quite a lot.
> 
> ```
> $ sudo dmesg
> […]
> [0.318412] initcall init_graph_trace+0x0/0x64 returned 0 after 
> 199218 usecs
> […]
> [1.770287] calling  event_trace_init+0x0/0x2c2 @ 1
> [2.052871] initcall event_trace_init+0x0/0x2c2 returned 0 after 
> 275942 usecs
> […]
> ```
> 
> Is there a way to disable tracing on the Linux kernel command line to 
> disable tracing?
> 

Try initcall_blacklist. But you acquire all risks when doing so. I
never tried it, so I have no idea what side effects that may have.

-- Steve

Re: How to disable tracing at runtime from the Linux kernel command line?

[Steven Rostedt]

On Sat, 14 Apr 2018 15:09:33 +0200
Paul Menzel  wrote:

> Dear Linux folks,
> 
> 
> I am trying to reduce the boot time of a standard Linux distribution 
> kernel. Currently, distributions – at least Debian und Ubuntu – enable 
> function tracing.
> 
> ```
> CONFIG_FTRACE=y
> CONFIG_FUNCTION_TRACER=y
> CONFIG_FUNCTION_GRAPH_TRACER=y
> 
> CONFIG_EVENT_TRACING=y
> ```
> 
> This is great, as it makes it easy to use tracing to hunt down things 
> holding up the boot. But it also skews the boot time quite a lot.
> 
> ```
> $ sudo dmesg
> […]
> [0.318412] initcall init_graph_trace+0x0/0x64 returned 0 after 
> 199218 usecs
> […]
> [1.770287] calling  event_trace_init+0x0/0x2c2 @ 1
> [2.052871] initcall event_trace_init+0x0/0x2c2 returned 0 after 
> 275942 usecs
> […]
> ```
> 
> Is there a way to disable tracing on the Linux kernel command line to 
> disable tracing?
> 

Try initcall_blacklist. But you acquire all risks when doing so. I
never tried it, so I have no idea what side effects that may have.

-- Steve

How to disable tracing at runtime from the Linux kernel command line?

[Paul Menzel]

Dear Linux folks,


I am trying to reduce the boot time of a standard Linux distribution 
kernel. Currently, distributions – at least Debian und Ubuntu – enable 
function tracing.


```
CONFIG_FTRACE=y
CONFIG_FUNCTION_TRACER=y
CONFIG_FUNCTION_GRAPH_TRACER=y

CONFIG_EVENT_TRACING=y
```

This is great, as it makes it easy to use tracing to hunt down things 
holding up the boot. But it also skews the boot time quite a lot.


```
$ sudo dmesg
[…]
[0.318412] initcall init_graph_trace+0x0/0x64 returned 0 after 
199218 usecs

[…]
[1.770287] calling  event_trace_init+0x0/0x2c2 @ 1
[2.052871] initcall event_trace_init+0x0/0x2c2 returned 0 after 
275942 usecs

[…]
```

Is there a way to disable tracing on the Linux kernel command line to 
disable tracing?



Kind regards,

Paul

How to disable tracing at runtime from the Linux kernel command line?

[Paul Menzel]

Dear Linux folks,


I am trying to reduce the boot time of a standard Linux distribution 
kernel. Currently, distributions – at least Debian und Ubuntu – enable 
function tracing.


```
CONFIG_FTRACE=y
CONFIG_FUNCTION_TRACER=y
CONFIG_FUNCTION_GRAPH_TRACER=y

CONFIG_EVENT_TRACING=y
```

This is great, as it makes it easy to use tracing to hunt down things 
holding up the boot. But it also skews the boot time quite a lot.


```
$ sudo dmesg
[…]
[0.318412] initcall init_graph_trace+0x0/0x64 returned 0 after 
199218 usecs

[…]
[1.770287] calling  event_trace_init+0x0/0x2c2 @ 1
[2.052871] initcall event_trace_init+0x0/0x2c2 returned 0 after 
275942 usecs

[…]
```

Is there a way to disable tracing on the Linux kernel command line to 
disable tracing?



Kind regards,

Paul