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    SubjectRe: [PATCH v3 08/10] x86/resctrl: Add the sysfs interface to read the event configuration
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    Hi Babu,

    On 8/22/2022 6:44 AM, Babu Moger wrote:
    > The current event configuration can be viewed by the user by reading
    > the sysfs configuration file.
    >
    > Following are the types of events supported.
    > ====================================================================
    > Bits Description
    > 6 Dirty Victims from the QOS domain to all types of memory
    > 5 Reads to slow memory in the non-local NUMA domain
    > 4 Reads to slow memory in the local NUMA domain
    > 3 Non-temporal writes to non-local NUMA domain
    > 2 Non-temporal writes to local NUMA domain
    > 1 Reads to memory in the non-local NUMA domain
    > 0 Reads to memory in the local NUMA domain
    >
    > By default the mbm_total_bytes configuration is set to 0x7f to count
    > all the types of events and mbm_local_bytes configuration is set to
    > 0x15 to count all the local memory events.
    >
    > $cat /sys/fs/resctrl/mon_data/mon_L3_00/mbm_total_config
    > 0x7f
    >
    > $cat /sys/fs/resctrl/mon_data/mon_L3_00/mbm_local_config
    > 0x15
    >
    > Signed-off-by: Babu Moger <babu.moger@amd.com>
    > Reviewed-by: Ingo Molnar <mingo@kernel.org>
    > ---
    > arch/x86/kernel/cpu/resctrl/internal.h | 21 ++++++++++
    > arch/x86/kernel/cpu/resctrl/rdtgroup.c | 70 ++++++++++++++++++++++++++++++++
    > 2 files changed, 91 insertions(+)
    >
    > diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
    > index fc725f5e9024..457666709386 100644
    > --- a/arch/x86/kernel/cpu/resctrl/internal.h
    > +++ b/arch/x86/kernel/cpu/resctrl/internal.h
    > @@ -15,6 +15,7 @@
    > #define MSR_IA32_MBA_THRTL_BASE 0xd50
    > #define MSR_IA32_MBA_BW_BASE 0xc0000200
    > #define MSR_IA32_SMBA_BW_BASE 0xc0000280
    > +#define MSR_IA32_EVT_CFG_BASE 0xc0000400
    >
    > #define MSR_IA32_QM_CTR 0x0c8e
    > #define MSR_IA32_QM_EVTSEL 0x0c8d
    > @@ -50,6 +51,26 @@
    > */
    > #define MBM_CNTR_WIDTH_OFFSET_MAX (62 - MBM_CNTR_WIDTH_BASE)
    >
    > +/* Reads to Local DRAM Memory */
    > +#define READS_TO_LOCAL_MEM BIT(0)
    > +
    > +/* Reads to Remote DRAM Memory */
    > +#define READS_TO_REMOTE_MEM BIT(1)
    > +
    > +/* Non-Temporal Writes to Local Memory */
    > +#define NON_TEMP_WRITE_TO_LOCAL_MEM BIT(2)
    > +
    > +/* Non-Temporal Writes to Remote Memory */
    > +#define NON_TEMP_WRITE_TO_REMOTE_MEM BIT(3)
    > +
    > +/* Reads to Local Memory the system identifies as "Slow Memory" */
    Seems unexpected character slipped into "identifies".

    > +#define READS_TO_LOCAL_S_MEM BIT(4)
    > +
    > +/* Reads to Remote Memory the system identifies as "Slow Memory" */

    here also

    > +#define READS_TO_REMOTE_S_MEM BIT(5)
    > +
    > +/* Dirty Victims to All Types of Memory */
    > +#define DIRTY_VICTIS_TO_ALL_MEM BIT(6)

    Is this intended to be "DIRTY_VICTIMS_TO_ALL_MEM" ?

    >
    > struct rdt_fs_context {
    > struct kernfs_fs_context kfc;
    > diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
    > index 30d2182d4fda..e1847d49fa15 100644
    > --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
    > +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
    > @@ -254,8 +254,78 @@ static const struct kernfs_ops kf_mondata_ops = {
    > .seq_show = rdtgroup_mondata_show,
    > };
    >
    > +/*
    > + * This is called via IPI to read the CQM/MBM counters
    > + * in a domain.
    > + */
    > +void mon_event_config_read(void *info)
    > +{
    > + union mon_data_bits *md = info;
    > + u32 evtid = md->u.evtid;
    > + u32 h, msr_index;
    > +
    > + switch (evtid) {
    > + case QOS_L3_MBM_TOTAL_EVENT_ID:
    > + msr_index = 0;
    > + break;
    > + case QOS_L3_MBM_LOCAL_EVENT_ID:
    > + msr_index = 1;
    > + break;
    > + default:
    > + return; /* Not expected to come here */

    Please no inline comments.

    > + }
    > +
    > + rdmsr(MSR_IA32_EVT_CFG_BASE + msr_index, md->u.mon_config, h);
    > +}
    > +
    > +void mondata_config_read(struct rdt_domain *d, union mon_data_bits *md)
    > +{
    > + smp_call_function_any(&d->cpu_mask, mon_event_config_read, md, 1);
    > +}
    > +
    > +int rdtgroup_mondata_config_show(struct seq_file *m, void *arg)
    > +{
    > + struct kernfs_open_file *of = m->private;
    > + struct rdt_hw_resource *hw_res;
    > + u32 resid, evtid, domid;
    > + struct rdtgroup *rdtgrp;
    > + struct rdt_resource *r;
    > + union mon_data_bits md;
    > + struct rdt_domain *d;
    > + int ret = 0;
    > +
    > + rdtgrp = rdtgroup_kn_lock_live(of->kn);
    > + if (!rdtgrp) {
    > + ret = -ENOENT;
    > + goto out;
    > + }
    > +
    > + md.priv = of->kn->priv;
    > + resid = md.u.rid;
    > + domid = md.u.domid;
    > + evtid = md.u.evtid;
    > +
    > + hw_res = &rdt_resources_all[resid];
    > + r = &hw_res->r_resctrl;
    > +
    > + d = rdt_find_domain(r, domid, NULL);
    > + if (IS_ERR_OR_NULL(d)) {
    > + ret = -ENOENT;
    > + goto out;
    > + }
    > +
    > + mondata_config_read(d, &md);
    > +
    > + seq_printf(m, "0x%x\n", md.u.mon_config);

    Looking at this patch and the next, the sysfs files are introduced to read
    from and write to the configuration register. From what I can tell the
    data is never used internally (what did I miss?). Why is the value of the
    configuration register stored?

    > +
    > +out:
    > + rdtgroup_kn_unlock(of->kn);
    > + return ret;
    > +}
    > +
    > static const struct kernfs_ops kf_mondata_config_ops = {
    > .atomic_write_len = PAGE_SIZE,
    > + .seq_show = rdtgroup_mondata_config_show,
    > };
    >
    > static bool is_cpu_list(struct kernfs_open_file *of)
    >
    >


    Reinette

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