mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2025-01-19 12:00:00 +00:00
176cda0619
To support performance measurement for KVM on PowerVM(KoP)
feature, PowerVM hypervisor has added couple of new software
counters in Virtual Process Area(VPA) of the partition.
Commit e1f288d2f9c69 ("KVM: PPC: Book3S HV nestedv2: Add
support for reading VPA counters for pseries guests")
have updated the paca fields with corresponding changes.
Proposed perf interface is to expose these new software
counters for monitoring of context switch latencies and
runtime aggregate. Perf interface driver is called
"vpa_pmu" and it has dependency on KVM and perf, hence
added new config called "VPA_PMU" which depends on
"CONFIG_KVM_BOOK3S_64_HV" and "CONFIG_HV_PERF_CTRS".
Since, kvm and kvm_host are currently compiled as built-in
modules, this perf interface takes the same path and
registered as a module.
vpa_pmu perf interface needs access to some of the kvm
functions and structures like kvmhv_get_l2_counters_status(),
hence kvm_book3s_64.h and kvm_ppc.h are included.
Below are the events added to monitor KoP:
vpa_pmu/l1_to_l2_lat/
vpa_pmu/l2_to_l1_lat/
vpa_pmu/l2_runtime_agg/
and vpa_pmu driver supports only per-cpu monitoring with this patch.
Example usage:
[command]# perf stat -e vpa_pmu/l1_to_l2_lat/ -a -I 1000
1.001017682 727,200 vpa_pmu/l1_to_l2_lat/
2.003540491 1,118,824 vpa_pmu/l1_to_l2_lat/
3.005699458 1,919,726 vpa_pmu/l1_to_l2_lat/
4.007827011 2,364,630 vpa_pmu/l1_to_l2_lat/
Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
Co-developed-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://patch.msgid.link/20241118114114.208964-1-kjain@linux.ibm.com
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.