Re: [PATCH v3 0/8] [RfC] fix tracing for modules

[Gerd Hoffmann]

  Hi,

> eg a trace point "dma_map_wait" gets mapped to probes in many
> .stp files, once per target, because we need to match based on
> the executable path:
> 
>   probe qemu.system.x86_64.dma_map_wait = 
> process("/usr/libexec/qemu-system-x86_64").mark("dma_map_wait")

So, that changes with modules, we need the module name now, i.e.

    probe qemu.system.x86_64.qxl_soft_reset = \
        
process("/home/kraxel/qemu-install/lib/qemu/hw-display-qxl.so").mark("qxl_soft_reset")

We could repeat that in every qemu-system-$arch.stp file.

We could also have one stp file per module, with probes like this:

    probe qemu.modules.qxl_soft_reset = \
        
process("/home/kraxel/qemu-install/lib/qemu/hw-display-qxl.so").mark("qxl_soft_reset")

The later looks like a better fit to me, but has the drawback that the
tracepoints have different names in modular and non-modular builds ...

take care,
  Gerd