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    Subject[PATCH 00/32] 2nd Iteration of Cache QoS Monitoring support.
    Date
    This series introduces the next iteration of kernel support for the
    Cache QoS Monitoring (CQM) technology available in Intel Xeon processors.

    One of the main limitations of the previous version is the inability
    to simultaneously monitor:
    1) cpu event and any other event in that cpu.
    2) cgroup events for cgroups in same descendancy line.
    3) cgroup events and any thread event of a cgroup in the same
    descendancy line.

    Another limitation is that monitoring for a cgroup was enabled/disabled by
    the existence of a perf event for that cgroup. Since the event
    llc_occupancy measures changes in occupancy rather than total occupancy,
    in order to read meaningful llc_occupancy values, an event should be
    enabled for a long enough period of time. The overhead in context switches
    caused by the perf events is undesired in some sensitive scenarios.

    This series of patches addresses the shortcomings mentioned above and,
    add some other improvements. The main changes are:
    - No more potential conflicts between different events. New
    version builds a hierarchy of RMIDs that captures the dependency
    between monitored cgroups. llc_occupancy for cgroup is the sum of
    llc_occupancies for that cgroup RMID and all other RMIDs in the
    cgroups subtree (both monitored cgroups and threads).

    - A cgroup integration that allows to monitor the a cgroup without
    creating a perf event, decreasing the context switch overhead.
    Monitoring is controlled by a boolean cgroup subsystem attribute
    in each perf cgroup, this is:

    echo 1 > cgroup_path/perf_event.cqm_cont_monitoring

    starts CQM monitoring whether or not there is a perf_event
    attached to the cgroup. Setting the attribute to 0 makes
    monitoring dependent on the existence of a perf_event.
    A perf_event is always required in order to read llc_occupancy.
    This cgroup integration uses Intel's PQR code and is intended to
    be used by upcoming versions of Intel's CAT.

    - A more stable rotation algorithm: New algorithm uses SLOs that
    guarantee:
    - A minimum of enabled time for monitored cgroups and
    threads.
    - A maximum time disabled before error is introduced by
    reusing dirty RMIDs.
    - A minimum rate at which RMIDs recycling must progress.

    - Reduced impact of stealing/rotation of RMIDs: The new algorithm
    accounts the residual occupancy held by limbo RMIDs towards the
    former owner of the limbo RMID, decreasing the error introduced
    by RMID rotation.
    It also allows a limbo RMID to be reused by its former owner when
    appropriate, decreasing the potential error of reusing dirty RMIDs
    and allowing to make progress even if most limbo RMIDs do not
    drop occupancy fast enough.

    - Elimination of pmu::count: perf generic's perf_event_count()
    perform a quick add of atomic types. The introduction of
    pmu::count in the previous CQM series to read occupancy for thread
    events changed the behavior of perf_event_count() by performing a
    potentially slow IPI and write/read to MSR. It also made pmu::read
    to have different behaviors depending on whether the event was a
    cpu/cgroup event or a thread. This patches serie removes the custom
    pmu::count from CQM and provides a consistent behavior for all
    calls of perf_event_read .

    - Added error return for pmu::read: Reads to CQM events may fail
    due to stealing of RMIDs, even after successfully adding an event
    to a PMU. This patch series expands pmu::read with an int return
    value and propagates the error to callers that can fail
    (ie. perf_read).
    The ability to fail of pmu::read is consistent with the recent
    changes that allow perf_event_read to fail for transactional
    reading of event groups.

    - Introduces the field pmu_event_flags that contain flags set by
    the PMU to signal variations on the default behavior to perf's
    generic code. In this series, three flags are introduced:
    - PERF_CGROUP_NO_RECURSION : Signals generic code to add
    events of the cgroup ancestors of a cgroup.
    - PERF_INACTIVE_CPU_READ_PKG: Signals generic coda that
    this CPU event can be read in any CPU in its event::cpu's
    package, even if the event is not active.
    - PERF_INACTIVE_EV_READ_ANY_CPU: Signals generic code that
    this event can be read in any CPU in any package in the
    system even if the event is not active.
    Using the above flags takes advantage of the CQM's hw ability to
    read llc_occupancy even when the associated perf event is not
    running in a CPU.

    This patch series also updates the perf tool to fix error handling and to
    better handle the idiosyncrasies of snapshot and per-pkg events.

    David Carrillo-Cisneros (31):
    perf/x86/intel/cqm: temporarily remove MBM from CQM and cleanup
    perf/x86/intel/cqm: remove check for conflicting events
    perf/x86/intel/cqm: remove all code for rotation of RMIDs
    perf/x86/intel/cqm: make read of RMIDs per package (Temporal)
    perf/core: remove unused pmu->count
    x86/intel,cqm: add CONFIG_INTEL_RDT configuration flag and refactor
    PQR
    perf/x86/intel/cqm: separate CQM PMU's attributes from x86 PMU
    perf/x86/intel/cqm: prepare for next patches
    perf/x86/intel/cqm: add per-package RMIDs, data and locks
    perf/x86/intel/cqm: basic RMID hierarchy with per package rmids
    perf/x86/intel/cqm: (I)state and limbo prmids
    perf/x86/intel/cqm: add per-package RMID rotation
    perf/x86/intel/cqm: add polled update of RMID's llc_occupancy
    perf/x86/intel/cqm: add preallocation of anodes
    perf/core: add hooks to expose architecture specific features in
    perf_cgroup
    perf/x86/intel/cqm: add cgroup support
    perf/core: adding pmu::event_terminate
    perf/x86/intel/cqm: use pmu::event_terminate
    perf/core: introduce PMU event flag PERF_CGROUP_NO_RECURSION
    x86/intel/cqm: use PERF_CGROUP_NO_RECURSION in CQM
    perf/x86/intel/cqm: handle inherit event and inherit_stat flag
    perf/x86/intel/cqm: introduce read_subtree
    perf/core: introduce PERF_INACTIVE_*_READ_* flags
    perf/x86/intel/cqm: use PERF_INACTIVE_*_READ_* flags in CQM
    sched: introduce the finish_arch_pre_lock_switch() scheduler hook
    perf/x86/intel/cqm: integrate CQM cgroups with scheduler
    perf/core: add perf_event cgroup hooks for subsystem attributes
    perf/x86/intel/cqm: add CQM attributes to perf_event cgroup
    perf,perf/x86,perf/powerpc,perf/arm,perf/*: add int error return to
    pmu::read
    perf,perf/x86: add hook perf_event_arch_exec
    perf/stat: revamp error handling for snapshot and per_pkg events

    Stephane Eranian (1):
    perf/stat: fix bug in handling events in error state

    arch/alpha/kernel/perf_event.c | 3 +-
    arch/arc/kernel/perf_event.c | 3 +-
    arch/arm64/include/asm/hw_breakpoint.h | 2 +-
    arch/arm64/kernel/hw_breakpoint.c | 3 +-
    arch/metag/kernel/perf/perf_event.c | 5 +-
    arch/mips/kernel/perf_event_mipsxx.c | 3 +-
    arch/powerpc/include/asm/hw_breakpoint.h | 2 +-
    arch/powerpc/kernel/hw_breakpoint.c | 3 +-
    arch/powerpc/perf/core-book3s.c | 11 +-
    arch/powerpc/perf/core-fsl-emb.c | 5 +-
    arch/powerpc/perf/hv-24x7.c | 5 +-
    arch/powerpc/perf/hv-gpci.c | 3 +-
    arch/s390/kernel/perf_cpum_cf.c | 5 +-
    arch/s390/kernel/perf_cpum_sf.c | 3 +-
    arch/sh/include/asm/hw_breakpoint.h | 2 +-
    arch/sh/kernel/hw_breakpoint.c | 3 +-
    arch/sparc/kernel/perf_event.c | 2 +-
    arch/tile/kernel/perf_event.c | 3 +-
    arch/x86/Kconfig | 6 +
    arch/x86/events/amd/ibs.c | 2 +-
    arch/x86/events/amd/iommu.c | 5 +-
    arch/x86/events/amd/uncore.c | 3 +-
    arch/x86/events/core.c | 3 +-
    arch/x86/events/intel/Makefile | 3 +-
    arch/x86/events/intel/bts.c | 3 +-
    arch/x86/events/intel/cqm.c | 3847 +++++++++++++++++++++---------
    arch/x86/events/intel/cqm.h | 519 ++++
    arch/x86/events/intel/cstate.c | 3 +-
    arch/x86/events/intel/pt.c | 3 +-
    arch/x86/events/intel/rapl.c | 3 +-
    arch/x86/events/intel/uncore.c | 3 +-
    arch/x86/events/intel/uncore.h | 2 +-
    arch/x86/events/msr.c | 3 +-
    arch/x86/include/asm/hw_breakpoint.h | 2 +-
    arch/x86/include/asm/perf_event.h | 41 +
    arch/x86/include/asm/pqr_common.h | 74 +
    arch/x86/include/asm/processor.h | 4 +
    arch/x86/kernel/cpu/Makefile | 4 +
    arch/x86/kernel/cpu/pqr_common.c | 43 +
    arch/x86/kernel/hw_breakpoint.c | 3 +-
    arch/x86/kvm/pmu.h | 10 +-
    drivers/bus/arm-cci.c | 3 +-
    drivers/bus/arm-ccn.c | 3 +-
    drivers/perf/arm_pmu.c | 3 +-
    include/linux/perf_event.h | 91 +-
    kernel/events/core.c | 170 +-
    kernel/sched/core.c | 1 +
    kernel/sched/sched.h | 3 +
    kernel/trace/bpf_trace.c | 5 +-
    tools/perf/builtin-stat.c | 43 +-
    tools/perf/util/counts.h | 19 +
    tools/perf/util/evsel.c | 44 +-
    tools/perf/util/evsel.h | 8 +-
    tools/perf/util/stat.c | 35 +-
    54 files changed, 3746 insertions(+), 1337 deletions(-)
    create mode 100644 arch/x86/events/intel/cqm.h
    create mode 100644 arch/x86/include/asm/pqr_common.h
    create mode 100644 arch/x86/kernel/cpu/pqr_common.c

    --
    2.8.0.rc3.226.g39d4020

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