Re: [Qemu-devel] [RFC PATCH 0/3] Fix UST backend for LTTng 2.x

["Alex Bennée" <alex.bennee@linaro.org>]

mohamad.gebai@gmail.com writes:

> These patches fix the UST backend which got broken by LTTng 2.x.
>
> An interesting new feature in LTTng 2.x is that tracepoints now need to belong
> to a provider. A provider is a way to group tracepoints in a logical way, for
> instance tracepoints that belong to a specific file or subsystem. This would
> then allow users to enable all tracepoints of a specific provider at once.
>
> In these patches, only one provider is defined, which is called "ust" (and
> tracepoints are defined in generated-ust-provider.h). It would be interesting to
> take advantage of this feature in the future, separating tracepoints into
> multiple providers. Of course, this would require more modifications as well as
> a way to specify to which provider each tracepoint belongs in file trace-events.
>
I'm getting loads of compile failures like:

./trace/generated-tracers.h: In function ‘trace_esp_dma_enable’:
./trace/generated-tracers.h:3355:1: error: expected expression before ‘)’ token
./trace/generated-tracers.h:3355:1: error: expected expression before ‘)’ token
./trace/generated-tracers.h:3355:1: error: expected expression before ‘)’ token
./trace/generated-tracers.h:3355:1: error: implicit declaration of function ‘__tracepoint_cb_ust___esp_dma_enable’ [-Werror=implicit-function-declaration]
./trace/generated-tracers.h:3355:1: error: nested extern declaration of ‘__tracepoint_cb_ust___esp_dma_enable’ [-Werror=nested-externs]

The code looks like:

static inline void trace_esp_dma_enable(void)
{
    tracepoint(ust, esp_dma_enable, );
}

So I assume it's the included stuff that's falling over.

This is on Ubuntu 12.04 LTS with:

11:03 ajb@sloy/x86_64 [qemu.git] >dpkg -l | grep tng
ii  liblttng-ust-dev                                    2.0.2-0ubuntu1                                      LTTng 2.0 Userspace Tracer (development files)
ii  liblttng-ust0                                       2.0.2-0ubuntu1                                      LTTng 2.0 Userspace Tracer (libraries)

-- 
Alex Bennée