From 848942cb2ef584752d7c41594b2cc91229fe7f01 Mon Sep 17 00:00:00 2001 From: Changbin Du Date: Wed, 8 May 2019 23:21:17 +0800 Subject: [PATCH] Documentation: x86: convert topology.txt to reST This converts the plain text documentation to reStructuredText format and add it to Sphinx TOC tree. No essential content change. Signed-off-by: Changbin Du Reviewed-by: Mauro Carvalho Chehab Signed-off-by: Jonathan Corbet --- Documentation/x86/index.rst | 1 + .../x86/{topology.txt => topology.rst} | 92 ++++++++++--------- 2 files changed, 49 insertions(+), 44 deletions(-) rename Documentation/x86/{topology.txt => topology.rst} (74%) diff --git a/Documentation/x86/index.rst b/Documentation/x86/index.rst index d7fc8efac192..da89bf0ad69f 100644 --- a/Documentation/x86/index.rst +++ b/Documentation/x86/index.rst @@ -9,3 +9,4 @@ x86-specific Documentation :numbered: boot + topology diff --git a/Documentation/x86/topology.txt b/Documentation/x86/topology.rst similarity index 74% rename from Documentation/x86/topology.txt rename to Documentation/x86/topology.rst index 2953e3ec9a02..5176e5315faa 100644 --- a/Documentation/x86/topology.txt +++ b/Documentation/x86/topology.rst @@ -1,3 +1,6 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============ x86 Topology ============ @@ -33,14 +36,14 @@ The topology of a system is described in the units of: - cores - threads -* Package: - - Packages contain a number of cores plus shared resources, e.g. DRAM - controller, shared caches etc. +Package +======= +Packages contain a number of cores plus shared resources, e.g. DRAM +controller, shared caches etc. - AMD nomenclature for package is 'Node'. +AMD nomenclature for package is 'Node'. - Package-related topology information in the kernel: +Package-related topology information in the kernel: - cpuinfo_x86.x86_max_cores: @@ -66,40 +69,41 @@ The topology of a system is described in the units of: - cpu_llc_id: A per-CPU variable containing: - - On Intel, the first APIC ID of the list of CPUs sharing the Last Level - Cache - - On AMD, the Node ID or Core Complex ID containing the Last Level - Cache. In general, it is a number identifying an LLC uniquely on the - system. + - On Intel, the first APIC ID of the list of CPUs sharing the Last Level + Cache -* Cores: + - On AMD, the Node ID or Core Complex ID containing the Last Level + Cache. In general, it is a number identifying an LLC uniquely on the + system. - A core consists of 1 or more threads. It does not matter whether the threads - are SMT- or CMT-type threads. +Cores +===== +A core consists of 1 or more threads. It does not matter whether the threads +are SMT- or CMT-type threads. - AMDs nomenclature for a CMT core is "Compute Unit". The kernel always uses - "core". +AMDs nomenclature for a CMT core is "Compute Unit". The kernel always uses +"core". - Core-related topology information in the kernel: +Core-related topology information in the kernel: - smp_num_siblings: The number of threads in a core. The number of threads in a package can be - calculated by: + calculated by:: threads_per_package = cpuinfo_x86.x86_max_cores * smp_num_siblings -* Threads: +Threads +======= +A thread is a single scheduling unit. It's the equivalent to a logical Linux +CPU. - A thread is a single scheduling unit. It's the equivalent to a logical Linux - CPU. +AMDs nomenclature for CMT threads is "Compute Unit Core". The kernel always +uses "thread". - AMDs nomenclature for CMT threads is "Compute Unit Core". The kernel always - uses "thread". - - Thread-related topology information in the kernel: +Thread-related topology information in the kernel: - topology_core_cpumask(): @@ -113,15 +117,15 @@ The topology of a system is described in the units of: The cpumask contains all online threads in the core to which a thread belongs. - - topology_logical_package_id(): + - topology_logical_package_id(): The logical package ID to which a thread belongs. - - topology_physical_package_id(): + - topology_physical_package_id(): The physical package ID to which a thread belongs. - - topology_core_id(); + - topology_core_id(); The ID of the core to which a thread belongs. It is also printed in /proc/cpuinfo "core_id." @@ -129,41 +133,41 @@ The topology of a system is described in the units of: System topology examples +======================== -Note: - -The alternative Linux CPU enumeration depends on how the BIOS enumerates the -threads. Many BIOSes enumerate all threads 0 first and then all threads 1. -That has the "advantage" that the logical Linux CPU numbers of threads 0 stay -the same whether threads are enabled or not. That's merely an implementation -detail and has no practical impact. +.. note:: + The alternative Linux CPU enumeration depends on how the BIOS enumerates the + threads. Many BIOSes enumerate all threads 0 first and then all threads 1. + That has the "advantage" that the logical Linux CPU numbers of threads 0 stay + the same whether threads are enabled or not. That's merely an implementation + detail and has no practical impact. -1) Single Package, Single Core +1) Single Package, Single Core:: [package 0] -> [core 0] -> [thread 0] -> Linux CPU 0 2) Single Package, Dual Core - a) One thread per core + a) One thread per core:: [package 0] -> [core 0] -> [thread 0] -> Linux CPU 0 -> [core 1] -> [thread 0] -> Linux CPU 1 - b) Two threads per core + b) Two threads per core:: [package 0] -> [core 0] -> [thread 0] -> Linux CPU 0 -> [thread 1] -> Linux CPU 1 -> [core 1] -> [thread 0] -> Linux CPU 2 -> [thread 1] -> Linux CPU 3 - Alternative enumeration: + Alternative enumeration:: [package 0] -> [core 0] -> [thread 0] -> Linux CPU 0 -> [thread 1] -> Linux CPU 2 -> [core 1] -> [thread 0] -> Linux CPU 1 -> [thread 1] -> Linux CPU 3 - AMD nomenclature for CMT systems: + AMD nomenclature for CMT systems:: [node 0] -> [Compute Unit 0] -> [Compute Unit Core 0] -> Linux CPU 0 -> [Compute Unit Core 1] -> Linux CPU 1 @@ -172,7 +176,7 @@ detail and has no practical impact. 4) Dual Package, Dual Core - a) One thread per core + a) One thread per core:: [package 0] -> [core 0] -> [thread 0] -> Linux CPU 0 -> [core 1] -> [thread 0] -> Linux CPU 1 @@ -180,7 +184,7 @@ detail and has no practical impact. [package 1] -> [core 0] -> [thread 0] -> Linux CPU 2 -> [core 1] -> [thread 0] -> Linux CPU 3 - b) Two threads per core + b) Two threads per core:: [package 0] -> [core 0] -> [thread 0] -> Linux CPU 0 -> [thread 1] -> Linux CPU 1 @@ -192,7 +196,7 @@ detail and has no practical impact. -> [core 1] -> [thread 0] -> Linux CPU 6 -> [thread 1] -> Linux CPU 7 - Alternative enumeration: + Alternative enumeration:: [package 0] -> [core 0] -> [thread 0] -> Linux CPU 0 -> [thread 1] -> Linux CPU 4 @@ -204,7 +208,7 @@ detail and has no practical impact. -> [core 1] -> [thread 0] -> Linux CPU 3 -> [thread 1] -> Linux CPU 7 - AMD nomenclature for CMT systems: + AMD nomenclature for CMT systems:: [node 0] -> [Compute Unit 0] -> [Compute Unit Core 0] -> Linux CPU 0 -> [Compute Unit Core 1] -> Linux CPU 1 -- 2.20.1