[ Upstream commit 9981bace85d816ed8724ac46e49285e8488d29e6 ] At debugfs/kvm/<pid>/vcpu0/timings we show how long each part of the code takes to run: $ cat /sys/kernel/debug/kvm/*-*/vcpu0/timings rm_entry: 123785 49398892 118 4898 rm_intr: 123780 6075890 22 390 rm_exit: 0 0 0 0 <-- NOK guest: 123780 46732919988 402 9997638 cede: 0 0 0 0 <-- OK, no cede napping in P9 The "rm_exit" is always showing zero because it is the last one and end_timing does not increment the counter of the previous entry. We can fix it by calling accumulate_time again instead of end_timing. That way the counter gets incremented. The rest of the arithmetic can be ignored because there are no timing points after this and the accumulators are reset before the next round. Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220525130554.2614394-2-farosas@linux.ibm.com Signed-off-by: Sasha Levin <sashal@kernel.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.
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