perfctr-2.6.0-pre2 released

Mikael Pettersson (
Sun, 13 Jul 2003 23:34:46 +0200 (MEST)

Version 2.6.0-pre2 of perfctr, the Linux/x86 performance
monitoring counters driver, is now available at the usual

Although this release makes the mmap()ed counter state compatible
between x86 and x86-64, there are still several unresolved ABI
compatibility problems (not just x86 on x86-64 but also protection
for future drivers versions). I have the choice of either doing
ad-hoc solutions for each data relevant structure (info, counter sums,
counter control), or go with a generic sparse marshalling approach.
The latter has been prototyped and _will_ work, but it's a radical
departure from conventional kernel/user-space APIs.

Version 2.6.0-pre2, 2003-07-13
- Per-process perfctrs API fixes: control data is retrieved using
new READ_CONTROL operation, mmap()ed state no longer exposes the
control data, the SAMPLE operation is renamed to READ_SUM and
now updates a given user-space buffer, non-write operations are
permitted on dead perfctrs.
Retrieving control explicitly makes the user-visible mmap()ed
state binary compatible between x86 and x86-64. The other changes
simplify the user-space library and allow perfex to replace raw
mmap() accesses with higher-level operations.
- Driver cleanups, including eliminating many #ifdefs and
removing some unnecessary P4-specific driver procedures.
- Fixes for macro redefinition warnings in the 2.4.22-pre3 kernel.
- Perfctr library RPM spec file updates from Bryan O'Sullivan.

/ Mikael Pettersson
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