On Thursday, October 19, 2006 12:50 PM, David Smith wrote:
Frank Ch. Eigler wrote:
kernel.function("*") should match exactly what was there before.
Probes on module("*").FOO would be redefined to mean something like
"all modules that we know at translation time that *might* exist,
that also happen to be *loaded* at run time. This aspect of wildcard
expansion would thus take place at run time rather than translate
time. It just so happens that the same module might probe a greater
or lesser number of modules on an actual system. With that proviso,
a script-source-level hash still seems to work.
[...]
The hash is computed using the following data:
[...]
- pass 2 script output
[...]
Stuff left to do:
- Testing, testing, testing
- Correct module handling (which Frank outlined above)
Actually, correct module handling should already be covered if you're
hashing the pass-2 output. Pass-2 is elaboration, which uses debuginfo
to locate the actual probe points. Suppose I run a script like this:
probe module("*").function("*interrupt*") { log(probefunc()) }
Pass-2 output will include all of the probe points matching my wildcard:
...
module("ahci").function("ahci_interrupt@drivers/scsi/ahci.c:889"),
module("libata").function("ata_interrupt@drivers/scsi/libata-core.c:4198
"),
...
If I then load a new module that also has a "*interrupt*" function, the
pass-2 output will include the new probe point, and will thus get a
different hash.