mirror of https://gitee.com/openkylin/linux.git
8e8a31d7fd
POWER9 SMT8 cores consist of two groups of threads, where threads in each group shares L1-cache. The scheduler is not aware of this distinction as the current sched-domain hierarchy has all the threads of the core defined at the SMT domain. SMT [Thread siblings of the SMT8 core] DIE [CPUs in the same die] NUMA [All the CPUs in the system] Due to this, we can observe run-to-run variance when we run a multi-threaded benchmark bound to a single core based on how the scheduler spreads the software threads across the two groups in the core. We fix this in this patch by defining each group of threads which share L1-cache to be the SMT level. The group of threads in the SMT8 core is defined to be the CACHE level. The sched-domain hierarchy after this patch will be : SMT [Thread siblings in the core that share L1 cache] CACHE [Thread siblings that are in the SMT8 core] DIE [CPUs in the same die] NUMA [All the CPUs in the system] Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> |
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README
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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.