perfctr-2.4.3 is now available at the usual place:
http://www.csd.uu.se/~mikpe/linux/perfctr/
Users of hyper-threaded Pentium 4s (Xeons) are strongly
recommended to upgrade to this release. Older releases
may silently malfunction due to the resource conflicts
mentioned in the CHANGES extract below.
Version 2.4.3, 2002-12-11
- Support for hyper-threaded Pentium 4s added. In a HT P4, the
two logical processors share the performance counter state.
HT P4s are therefore _asymmetric_ multi-processors, and the
driver enforces CPU affinity masks on users of per-process
performance counters to avoid resource conflicts. (Users are
restricted to logical processor #0 in each physical CPU.)
Limitations:
* The kernel mechanism for updating a process' CPU affinity
mask uses no or very weak locking, which makes certain race
conditions possible that can break the driver's CPU affinity
mask restrictions. For now, users should NOT use the
sched_setaffinity() system call on processes using per-process
performance counters.
* Global-mode performance counters don't work on HT P4s due to
limitations in the API. This will be fixed in perfctr-2.5.
* 2.2 kernels don't have CPU affinity masks, and therefore can't
support HT P4s.
/ Mikael Pettersson
-
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This archive was generated by hypermail 2b29 : Sun Dec 15 2002 - 22:00:21 EST