Revision 7178fb0b239d1c037876301c116fc9a6c1bd2ac0 authored by Linus Torvalds on 05 May 2019, 21:37:25 UTC, committed by Linus Torvalds on 05 May 2019, 21:37:25 UTC
Pull perf fixes from Ingo Molnar: "I'd like to apologize for this very late pull request: I was dithering through the week whether to send the fixes, and then yesterday Jiri's crash fix for a regression introduced in this cycle clearly marked perf/urgent as 'must merge now'. Most of the commits are tooling fixes, plus there's three kernel fixes via four commits: - race fix in the Intel PEBS code - fix an AUX bug and roll back a previous attempt - fix AMD family 17h generic HW cache-event perf counters The largest diffstat contribution comes from the AMD fix - a new event table is introduced, which is a fairly low risk change but has a large linecount" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/x86/intel: Fix race in intel_pmu_disable_event() perf/x86/intel/pt: Remove software double buffering PMU capability perf/ring_buffer: Fix AUX software double buffering perf tools: Remove needless asm/unistd.h include fixing build in some places tools arch uapi: Copy missing unistd.h headers for arc, hexagon and riscv tools build: Add -ldl to the disassembler-four-args feature test perf cs-etm: Always allocate memory for cs_etm_queue::prev_packet perf cs-etm: Don't check cs_etm_queue::prev_packet validity perf report: Report OOM in status line in the GTK UI perf bench numa: Add define for RUSAGE_THREAD if not present tools lib traceevent: Change tag string for error perf annotate: Fix build on 32 bit for BPF annotation tools uapi x86: Sync vmx.h with the kernel perf bpf: Return value with unlocking in perf_env__find_btf() MAINTAINERS: Include vendor specific files under arch/*/events/* perf/x86/amd: Update generic hardware cache events for Family 17h
Kconfig.preempt
choice
prompt "Preemption Model"
default PREEMPT_NONE
config PREEMPT_NONE
bool "No Forced Preemption (Server)"
help
This is the traditional Linux preemption model, geared towards
throughput. It will still provide good latencies most of the
time, but there are no guarantees and occasional longer delays
are possible.
Select this option if you are building a kernel for a server or
scientific/computation system, or if you want to maximize the
raw processing power of the kernel, irrespective of scheduling
latencies.
config PREEMPT_VOLUNTARY
bool "Voluntary Kernel Preemption (Desktop)"
depends on !ARCH_NO_PREEMPT
help
This option reduces the latency of the kernel by adding more
"explicit preemption points" to the kernel code. These new
preemption points have been selected to reduce the maximum
latency of rescheduling, providing faster application reactions,
at the cost of slightly lower throughput.
This allows reaction to interactive events by allowing a
low priority process to voluntarily preempt itself even if it
is in kernel mode executing a system call. This allows
applications to run more 'smoothly' even when the system is
under load.
Select this if you are building a kernel for a desktop system.
config PREEMPT
bool "Preemptible Kernel (Low-Latency Desktop)"
depends on !ARCH_NO_PREEMPT
select PREEMPT_COUNT
select UNINLINE_SPIN_UNLOCK if !ARCH_INLINE_SPIN_UNLOCK
help
This option reduces the latency of the kernel by making
all kernel code (that is not executing in a critical section)
preemptible. This allows reaction to interactive events by
permitting a low priority process to be preempted involuntarily
even if it is in kernel mode executing a system call and would
otherwise not be about to reach a natural preemption point.
This allows applications to run more 'smoothly' even when the
system is under load, at the cost of slightly lower throughput
and a slight runtime overhead to kernel code.
Select this if you are building a kernel for a desktop or
embedded system with latency requirements in the milliseconds
range.
endchoice
config PREEMPT_COUNT
bool
![swh spinner](/static/img/swh-spinner.gif)
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