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* What's new since version 0.5.12?
- When running in -p4 (compile-only) mode, the compiled .ko file name
is printed on standard output.
- An array element with a null value such as zero or an empty string
is now preserved, and will show up in a "foreach" loop or "in" test.
To delete such an element, the scripts needs to use an explicit
"delete array[idx]" statement rather than something like "array[idx]=0".
- The new "-P" option controls whether prologue searching heuristics
will be activated for function probes. This was needed to get correct
debugging information (dwarf location list) data for $target variables.
Modern compilers (gcc 4.1+) tend not to need this heuristic, so it is
no longer default. A new configure flag (--enable-prologues) restores
it as a default setting, and is appropriate for older compilers (gcc 3.*).
- Each systemtap module prints a one-line message to the kernel informational
log when it starts. This line identifies the translator version, base
address of the probe module, a broken-down memory consumption estimate, and
the total number of probes. This is meant as a debugging / auditing aid.
- Begin/end probes are run with interrupts enabled (but with
preemption disabled). This will allow begin/end probes to be
longer, to support generating longer reports.
* What's new since version 0.5.10?
- Offline processing of debugging information, enabling general
cross-compilation of probe scripts to remote hosts, without
requiring identical module/memory layout. This slows down
compilation/translation somewhat.
- Kernel symbol table data is loaded by staprun at startup time
rather than compiled into the module.
- Support the "limit" keyword for foreach iterations:
foreach ([x,y] in ary limit 5) { ... }
This implicitly exits after the fifth iteration. It also enables
more efficient key/value sorting.
- Support the "maxactive" keyword for return probes:
probe kernel.function("sdfsdf").maxactive(848) { ... }
This allows up to 848 concurrently outstanding entries to
the sdfsdf function before one returns. The default maxactive
number is smaller, and can result in missed return probes.
- Support accessing of saved function arguments from within
return probes. These values are saved by a synthesized
function-entry probe.
- Add substantial version/architecture checking in compiled probes to
assert correct installation of debugging information and correct
execution on a compatible kernel.
- Add probe-time checking for sufficient free stack space when probe
handlers are invoked, as a safety improvement.
- Add an optional numeric parameter for begin/end probe specifications,
to order their execution.
probe begin(10) { } /* comes after */ probe begin(-10) {}
- Add an optional array size declaration, which is handy for very small
or very large ones.
global little[5], big[20000]
- Include some example scripts along with the documentation.
- Change the start-time allocation of probe memory to avoid causing OOM
situations, and to abort cleanly if free kernel memory is short.
- Automatically use the kernel DWARF unwinder, if present, for stack
tracebacks.
- Many minor bug fixes, performance, tapset, and error message
improvements.
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