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== Detailed Description == | == Detailed Description == | ||
By packaging a new version of systemtap, that enables programs that already have static dtrace probe markers in their sources and by making those packages depend on the new systemtap | By packaging a new version of systemtap, that enables programs that already have static dtrace probe markers in their sources and by making those packages build depend on the new systemtap-sdt-devel package and recompiling them with probe points enabled, users of those packages will be able to trace any high level events that these packages provide. | ||
== Benefit to Fedora == | == Benefit to Fedora == | ||
Revision as of 17:41, 19 January 2009
Feature Name
Systemtap Static Probes for userspace programs.
Summary
Systemtap allows event tracing of programs when they have static probes inserted. This allows for tracing specifics of an application on a higher level that is meaningful to the application user so they don't have to know the exact source code details for tracing what is happening.
Owner
- Name: Mark Wielaard
- email: mjw@redhat.com
Current status
- Targeted release: Fedora 11
- Last updated: January 19 2009
- Percentage of completion: 5%
Detailed Description
By packaging a new version of systemtap, that enables programs that already have static dtrace probe markers in their sources and by making those packages build depend on the new systemtap-sdt-devel package and recompiling them with probe points enabled, users of those packages will be able to trace any high level events that these packages provide.
Benefit to Fedora
It will be easier for developers and users to observe what is really happening on their system on a higher (application) level.
Scope
- Work with upstream to identify any issues with the new capabilities while we activate probes in packages.
- Package new version of Systemtap (including new subpackage systemtap-sdt-devel).
- Identify packages that already include static user probes (postgresql, java-1.6.0-openjdk, mysql, xorg-x11-server, ...)
- Work with package maintainer to enable them in the Fedora build spec file.
- Add documentation on enabled probes and how to use them with a systemtap tapset.
How To Test
- Need a specific pacakage list.
- For each package enabling probes a reference to the probe names.
- And an simple example stap invocation listing markers that can be enabled.
User Experience
For packages that have static probes enabled users will be able to trace high-level events, like for example database transactions, through stap.
Dependencies
- A new version of systemtap with the systemtap-sdt-devel subpackage.
- Any package wishing to expose existing probes in its (upstream) sources depending on systemtap-sdt-devel and adding an --enable-dtrace or equivalent to its spec file.
- Not required for this feature, but since systemtap uses debuginfo, this feature is enhanced by the Debug Info Revamp Feature.
Contingency Plan
Even if all the tracing will not work, packages that are converted to provide static probes will not be impacted since the probe points have (near) zero overhead, so in the worse case some packages were recompiled to enable the feature, but users will still not be able to use it.
Documentation
The upstream wiki is the best description for now http://sourceware.org/systemtap/wiki/UsingStaticUserMarkers the systemtap list has an example on converting a package http://sourceware.org/ml/systemtap/2009-q1/msg00140.html
While working on this feature this section will be expanded to list packages that have probe points enabled and pointers to (upstream) package documentation on the probe names and semantics like for postgresql http://www.postgresql.org/docs/8.2/static/dynamic-trace.html
Release Notes
- FIXME: Should have some notes about the feature and which packages were enabled when finished.
Comments and Discussion