This set of patches add perfctr-2.7.2, the performance-monitoring counters driver, to kernel 2.6.6-mm2. Based on comments from Andrew Morton, this version: - switches to a new syscall instead of ioctl()s - is split in several logically distinct parts Summary: perfctr drives the performance counters in i386, x86_64, and PowerPC processors. It supports virtualised per-process counters with low-overhead user-space sampling, and global-mode counters for system-wide measurements. Perfctr has been in use for several years, at major HPC centres and among various researchers, for application-level performance measurements. Documentation is limited at the moment. We're working on it. Invariably, kernel hackers ask how perfctr differs from oprofile. The short answer is that oprofile and perfctr are based on different approaches with different goals. Perfctr is primarily about allowing application developers to count performance- related events in application code. Overflow interrupts can be caught for profiling purposes, when the hardware and kernel allow this, but the counts themselves are the primary objects of interest. Oprofile primarily does interrupt-driven profiling using various clock-like interrupt sources, one of which may be the CPU's performance counters. The set of patches that follow are: 1/7: core driver files and kernel changes 2/7: i386 driver and arch changes 3/7: x86_64 driver and arch changes 4/7: PowerPC driver and arch changes 5/7: driver for virtualised (per-process) performance counters 6/7: driver for global-mode (system-wide) performance counters 7/7: remaining small changes /Mikael Pettersson