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3daa96d672
Perfmon-v4 counter freezing is fundamentally broken; remove this default disabled code to make sure nobody uses it. The feature is called Freeze-on-PMI in the SDM, and if it would do that, there wouldn't actually be a problem, *however* it does something subtly different. It globally disables the whole PMU when it raises the PMI, not when the PMI hits. This means there's a window between the PMI getting raised and the PMI actually getting served where we loose events and this violates the perf counter independence. That is, a counting event should not result in a different event count when there is a sampling event co-scheduled. This is known to break existing software (RR). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.