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 reStructuredText 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.
Clone this repository
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Download tar.gz
PMT directories exposed in sysfs use the following pattern:
telem%u
for example:
telem0, telem2, telem3, ..., telem15, telem16
This naming scheme preserves the ordering from the PCIe discovery, which
is important to correctly map the telemetry directory to the specific
domain (cpu, core, package etc).
Because readdir() traverses the entries in alphabetical order, causing
for example "telem13" to be traversed before "telem3", it is necessary
to use scandir() with custom compare() callback to preserve the PCIe
ordering.
Signed-off-by: Patryk Wlazlyn <patryk.wlazlyn@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
When platforms expose multiple PMT aggregators with the same GUID, the
only way to identify them and map to specific domain is by reading them
in an order they were exposed via PCIe. Intel PMT kernel driver does
keep the same order and numbers the telemetry directories accordingly.
Use GUID and sequence number (order) to uniquely identify PMT
aggregators.
Signed-off-by: Patryk Wlazlyn <patryk.wlazlyn@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
When requesting PMT counters with --add command, user may want to skip
specifying values for all the domains (that is, cpu, core, package etc).
For the domains that user did not provide information on how to read the
counter, return default value - zero.
Signed-off-by: Patryk Wlazlyn <patryk.wlazlyn@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
For some MSRs, for example, the Platform Energy Counter (RAPL PSYS), it
is required to additionally check for a non-zero value to confirm that
it is present.
From Intel SDM vol. 4:
Platform Energy Counter (R/O)
This MSR is valid only if both platform vendor hardware
implementation and BIOS enablement support it.
This MSR will read 0 if not valid.
Signed-off-by: Patryk Wlazlyn <patryk.wlazlyn@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Include procfs and sysfs data collection time in the system summary
row of the "usec" column. This is useful for isolating where the
time goes during turbostat data collection.
Background:
Column "usec" shows
1. the number of microseconds elapsed during counter collection,
including thread migration -- if any, for each CPU row.
2. total elapsed time to collect the counters on all cpus, for the
summary row.
This can be used to check the time cost of a give column. For example,
run below commands separately
turbostat --show usec sleep 1
turbostat --show usec,CoreTmp sleep 1
and the delta in the usec column will tell the time cost for CoreTmp
(Thermal MSR read)
Problem:
Some of the kernel procfs/sysfs accesses are expensive, especially on
high core count systems. "usec" column cannot tell this because it only
includes the time cost of the counters.
Solution:
Leave the per CPU "usec" as it is and modify the summary "usec" to
include the time cost of the procfs/sysfs snapshot.
With it, the "usec" column can be used to get
1. the baseline, e.g.
turbostat --show usec sleep 1
2. the baseline + some per CPU counter cost, e.g.
turbostat --show usec,CoreTmp sleep 1
3. the baseline + some per CPU sysfs cost, e.g.
turbostat --show usec,C1 sleep 1
4. the baseline + /proc/interrupts cost, e.g
turbostat --show usec,IRQ sleep 1
Man-page update is also included.
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Intel Sapphire Rapids is an exception and has fixed divisor for RAPL PSYS
counter set to 1.0. Add a platform bit and enable it for SPR.
Reported-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Patryk Wlazlyn <patryk.wlazlyn@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
This (the old code) is just not how you round up to a page size.
Noticed on a recent Intel platform. Previous ones must have been
reporting sizes already aligned to a page and so the bug was missed when
testing.
Fixes: f0e4ed752fda ("tools/power turbostat: Add early support for PMT counters")
Signed-off-by: Patryk Wlazlyn <patryk.wlazlyn@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
The counter is present on most supporting Intel platforms and provides
useful data to the user. There is no reason to disable the counter by
default.
Signed-off-by: Patryk Wlazlyn <patryk.wlazlyn@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Add an NMI column, a proper sub-set of the IRQ column.
It would be preferable if the kernel exported
/sys/kernel/irq/NMI/per_cpu_count.
But since we are already forced to parse /proc/interrupts,
noticing which row is the NMI is simple enough.
Suggested-by: Artem Bityutskiy <artem.bityutskiy@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Suggested-by: Artem Bityutskiy <artem.bityutskiy@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Turbostat currently exits under the following conditions:
1. When running on non-Intel/AMD/Hygon x86 vendors.
2. When running on Intel models that lack specific platform features.
Introduce a new `--force` parameter that allows turbostat to run on
these unsupported platforms with minimal default feature support. This
provides users with the flexibility to gather basic information even on
unsupported systems.
[lenb: updated warning message text]
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Improve the `--help` output of turbostat by standardizing the format
and enhancing readability. The following changes are made to ensure
consistency and clarity in the help message:
1. Use a consistent pattern for each parameter's help message:
- Display the parameter and its input (if any) on the same line,
separated by a space.
- Provide the detailed description on a separate line.
2. Ensure that the first character of each description is in lower-case.
These changes make the help output more uniform and easier to read,
helping users quickly understand the available options and their usage.
No functional change.
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Turbostat currently supports x86 processors from Intel, AMD, and Hygon.
The behavior of turbostat on CPUs from other vendors has not been
evaluated and may lead to incorrect or undefined behavior.
Enhance turbostat to exit by default when running on an unsupported CPU
vendor. This ensures that users are aware that their CPU is not
currently supported by turbostat, guiding them to seek support for their
specific hardware through future patches.
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Turbostat requires per-platform enabling for Intel CPU models due to
platform-specific features. When running on unsupported Intel CPU
models, turbostat currently operates with limited default features,
which can lead to users unknowingly using an outdated version of the
tool.
Enhance turbostat to exit by default when run on unsupported Intel CPU
models, with a clear message to users, informing them that their CPU
model is not supported and advising them to update to the latest version
of turbostat for full functionality.
[lenb: updated error message wording]
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Clarify how to get the latest version.
Signed-off-by: Len Brown <len.brown@intel.com>