diff options
Diffstat (limited to 'arch/x86/kernel/cpu/perf_event_intel_cqm.c')
| -rw-r--r-- | arch/x86/kernel/cpu/perf_event_intel_cqm.c | 1391 |
1 files changed, 0 insertions, 1391 deletions
diff --git a/arch/x86/kernel/cpu/perf_event_intel_cqm.c b/arch/x86/kernel/cpu/perf_event_intel_cqm.c deleted file mode 100644 index a316ca96f1b6..000000000000 --- a/arch/x86/kernel/cpu/perf_event_intel_cqm.c +++ /dev/null @@ -1,1391 +0,0 @@ -/* - * Intel Cache Quality-of-Service Monitoring (CQM) support. - * - * Based very, very heavily on work by Peter Zijlstra. - */ - -#include <linux/perf_event.h> -#include <linux/slab.h> -#include <asm/cpu_device_id.h> -#include "perf_event.h" - -#define MSR_IA32_PQR_ASSOC 0x0c8f -#define MSR_IA32_QM_CTR 0x0c8e -#define MSR_IA32_QM_EVTSEL 0x0c8d - -static u32 cqm_max_rmid = -1; -static unsigned int cqm_l3_scale; /* supposedly cacheline size */ - -/** - * struct intel_pqr_state - State cache for the PQR MSR - * @rmid: The cached Resource Monitoring ID - * @closid: The cached Class Of Service ID - * @rmid_usecnt: The usage counter for rmid - * - * The upper 32 bits of MSR_IA32_PQR_ASSOC contain closid and the - * lower 10 bits rmid. The update to MSR_IA32_PQR_ASSOC always - * contains both parts, so we need to cache them. - * - * The cache also helps to avoid pointless updates if the value does - * not change. - */ -struct intel_pqr_state { - u32 rmid; - u32 closid; - int rmid_usecnt; -}; - -/* - * The cached intel_pqr_state is strictly per CPU and can never be - * updated from a remote CPU. Both functions which modify the state - * (intel_cqm_event_start and intel_cqm_event_stop) are called with - * interrupts disabled, which is sufficient for the protection. - */ -static DEFINE_PER_CPU(struct intel_pqr_state, pqr_state); - -/* - * Protects cache_cgroups and cqm_rmid_free_lru and cqm_rmid_limbo_lru. - * Also protects event->hw.cqm_rmid - * - * Hold either for stability, both for modification of ->hw.cqm_rmid. - */ -static DEFINE_MUTEX(cache_mutex); -static DEFINE_RAW_SPINLOCK(cache_lock); - -/* - * Groups of events that have the same target(s), one RMID per group. - */ -static LIST_HEAD(cache_groups); - -/* - * Mask of CPUs for reading CQM values. We only need one per-socket. - */ -static cpumask_t cqm_cpumask; - -#define RMID_VAL_ERROR (1ULL << 63) -#define RMID_VAL_UNAVAIL (1ULL << 62) - -#define QOS_L3_OCCUP_EVENT_ID (1 << 0) - -#define QOS_EVENT_MASK QOS_L3_OCCUP_EVENT_ID - -/* - * This is central to the rotation algorithm in __intel_cqm_rmid_rotate(). - * - * This rmid is always free and is guaranteed to have an associated - * near-zero occupancy value, i.e. no cachelines are tagged with this - * RMID, once __intel_cqm_rmid_rotate() returns. - */ -static u32 intel_cqm_rotation_rmid; - -#define INVALID_RMID (-1) - -/* - * Is @rmid valid for programming the hardware? - * - * rmid 0 is reserved by the hardware for all non-monitored tasks, which - * means that we should never come across an rmid with that value. - * Likewise, an rmid value of -1 is used to indicate "no rmid currently - * assigned" and is used as part of the rotation code. - */ -static inline bool __rmid_valid(u32 rmid) -{ - if (!rmid || rmid == INVALID_RMID) - return false; - - return true; -} - -static u64 __rmid_read(u32 rmid) -{ - u64 val; - - /* - * Ignore the SDM, this thing is _NOTHING_ like a regular perfcnt, - * it just says that to increase confusion. - */ - wrmsr(MSR_IA32_QM_EVTSEL, QOS_L3_OCCUP_EVENT_ID, rmid); - rdmsrl(MSR_IA32_QM_CTR, val); - - /* - * Aside from the ERROR and UNAVAIL bits, assume this thing returns - * the number of cachelines tagged with @rmid. - */ - return val; -} - -enum rmid_recycle_state { - RMID_YOUNG = 0, - RMID_AVAILABLE, - RMID_DIRTY, -}; - -struct cqm_rmid_entry { - u32 rmid; - enum rmid_recycle_state state; - struct list_head list; - unsigned long queue_time; -}; - -/* - * cqm_rmid_free_lru - A least recently used list of RMIDs. - * - * Oldest entry at the head, newest (most recently used) entry at the - * tail. This list is never traversed, it's only used to keep track of - * the lru order. That is, we only pick entries of the head or insert - * them on the tail. - * - * All entries on the list are 'free', and their RMIDs are not currently - * in use. To mark an RMID as in use, remove its entry from the lru - * list. - * - * - * cqm_rmid_limbo_lru - list of currently unused but (potentially) dirty RMIDs. - * - * This list is contains RMIDs that no one is currently using but that - * may have a non-zero occupancy value associated with them. The - * rotation worker moves RMIDs from the limbo list to the free list once - * the occupancy value drops below __intel_cqm_threshold. - * - * Both lists are protected by cache_mutex. - */ -static LIST_HEAD(cqm_rmid_free_lru); -static LIST_HEAD(cqm_rmid_limbo_lru); - -/* - * We use a simple array of pointers so that we can lookup a struct - * cqm_rmid_entry in O(1). This alleviates the callers of __get_rmid() - * and __put_rmid() from having to worry about dealing with struct - * cqm_rmid_entry - they just deal with rmids, i.e. integers. - * - * Once this array is initialized it is read-only. No locks are required - * to access it. - * - * All entries for all RMIDs can be looked up in the this array at all - * times. - */ -static struct cqm_rmid_entry **cqm_rmid_ptrs; - -static inline struct cqm_rmid_entry *__rmid_entry(u32 rmid) -{ - struct cqm_rmid_entry *entry; - - entry = cqm_rmid_ptrs[rmid]; - WARN_ON(entry->rmid != rmid); - - return entry; -} - -/* - * Returns < 0 on fail. - * - * We expect to be called with cache_mutex held. - */ -static u32 __get_rmid(void) -{ - struct cqm_rmid_entry *entry; - - lockdep_assert_held(&cache_mutex); - - if (list_empty(&cqm_rmid_free_lru)) - return INVALID_RMID; - - entry = list_first_entry(&cqm_rmid_free_lru, struct cqm_rmid_entry, list); - list_del(&entry->list); - - return entry->rmid; -} - -static void __put_rmid(u32 rmid) -{ - struct cqm_rmid_entry *entry; - - lockdep_assert_held(&cache_mutex); - - WARN_ON(!__rmid_valid(rmid)); - entry = __rmid_entry(rmid); - - entry->queue_time = jiffies; - entry->state = RMID_YOUNG; - - list_add_tail(&entry->list, &cqm_rmid_limbo_lru); -} - -static int intel_cqm_setup_rmid_cache(void) -{ - struct cqm_rmid_entry *entry; - unsigned int nr_rmids; - int r = 0; - - nr_rmids = cqm_max_rmid + 1; - cqm_rmid_ptrs = kmalloc(sizeof(struct cqm_rmid_entry *) * - nr_rmids, GFP_KERNEL); - if (!cqm_rmid_ptrs) - return -ENOMEM; - - for (; r <= cqm_max_rmid; r++) { - struct cqm_rmid_entry *entry; - - entry = kmalloc(sizeof(*entry), GFP_KERNEL); - if (!entry) - goto fail; - - INIT_LIST_HEAD(&entry->list); - entry->rmid = r; - cqm_rmid_ptrs[r] = entry; - - list_add_tail(&entry->list, &cqm_rmid_free_lru); - } - - /* - * RMID 0 is special and is always allocated. It's used for all - * tasks that are not monitored. - */ - entry = __rmid_entry(0); - list_del(&entry->list); - - mutex_lock(&cache_mutex); - intel_cqm_rotation_rmid = __get_rmid(); - mutex_unlock(&cache_mutex); - - return 0; -fail: - while (r--) - kfree(cqm_rmid_ptrs[r]); - - kfree(cqm_rmid_ptrs); - return -ENOMEM; -} - -/* - * Determine if @a and @b measure the same set of tasks. - * - * If @a and @b measure the same set of tasks then we want to share a - * single RMID. - */ -static bool __match_event(struct perf_event *a, struct perf_event *b) -{ - /* Per-cpu and task events don't mix */ - if ((a->attach_state & PERF_ATTACH_TASK) != - (b->attach_state & PERF_ATTACH_TASK)) - return false; - -#ifdef CONFIG_CGROUP_PERF - if (a->cgrp != b->cgrp) - return false; -#endif - - /* If not task event, we're machine wide */ - if (!(b->attach_state & PERF_ATTACH_TASK)) - return true; - - /* - * Events that target same task are placed into the same cache group. - */ - if (a->hw.target == b->hw.target) - return true; - - /* - * Are we an inherited event? - */ - if (b->parent == a) - return true; - - return false; -} - -#ifdef CONFIG_CGROUP_PERF -static inline struct perf_cgroup *event_to_cgroup(struct perf_event *event) -{ - if (event->attach_state & PERF_ATTACH_TASK) - return perf_cgroup_from_task(event->hw.target, event->ctx); - - return event->cgrp; -} -#endif - -/* - * Determine if @a's tasks intersect with @b's tasks - * - * There are combinations of events that we explicitly prohibit, - * - * PROHIBITS - * system-wide -> cgroup and task - * cgroup -> system-wide - * -> task in cgroup - * task -> system-wide - * -> task in cgroup - * - * Call this function before allocating an RMID. - */ -static bool __conflict_event(struct perf_event *a, struct perf_event *b) -{ -#ifdef CONFIG_CGROUP_PERF - /* - * We can have any number of cgroups but only one system-wide - * event at a time. - */ - if (a->cgrp && b->cgrp) { - struct perf_cgroup *ac = a->cgrp; - struct perf_cgroup *bc = b->cgrp; - - /* - * This condition should have been caught in - * __match_event() and we should be sharing an RMID. - */ - WARN_ON_ONCE(ac == bc); - - if (cgroup_is_descendant(ac->css.cgroup, bc->css.cgroup) || - cgroup_is_descendant(bc->css.cgroup, ac->css.cgroup)) - return true; - - return false; - } - - if (a->cgrp || b->cgrp) { - struct perf_cgroup *ac, *bc; - - /* - * cgroup and system-wide events are mutually exclusive - */ - if ((a->cgrp && !(b->attach_state & PERF_ATTACH_TASK)) || - (b->cgrp && !(a->attach_state & PERF_ATTACH_TASK))) - return true; - - /* - * Ensure neither event is part of the other's cgroup - */ - ac = event_to_cgroup(a); - bc = event_to_cgroup(b); - if (ac == bc) - return true; - - /* - * Must have cgroup and non-intersecting task events. - */ - if (!ac || !bc) - return false; - - /* - * We have cgroup and task events, and the task belongs - * to a cgroup. Check for for overlap. - */ - if (cgroup_is_descendant(ac->css.cgroup, bc->css.cgroup) || - cgroup_is_descendant(bc->css.cgroup, ac->css.cgroup)) - return true; - - return false; - } -#endif - /* - * If one of them is not a task, same story as above with cgroups. - */ - if (!(a->attach_state & PERF_ATTACH_TASK) || - !(b->attach_state & PERF_ATTACH_TASK)) - return true; - - /* - * Must be non-overlapping. - */ - return false; -} - -struct rmid_read { - u32 rmid; - atomic64_t value; -}; - -static void __intel_cqm_event_count(void *info); - -/* - * Exchange the RMID of a group of events. - */ -static u32 intel_cqm_xchg_rmid(struct perf_event *group, u32 rmid) -{ - struct perf_event *event; - struct list_head *head = &group->hw.cqm_group_entry; - u32 old_rmid = group->hw.cqm_rmid; - - lockdep_assert_held(&cache_mutex); - - /* - * If our RMID is being deallocated, perform a read now. - */ - if (__rmid_valid(old_rmid) && !__rmid_valid(rmid)) { - struct rmid_read rr = { - .value = ATOMIC64_INIT(0), - .rmid = old_rmid, - }; - - on_each_cpu_mask(&cqm_cpumask, __intel_cqm_event_count, - &rr, 1); - local64_set(&group->count, atomic64_read(&rr.value)); - } - - raw_spin_lock_irq(&cache_lock); - - group->hw.cqm_rmid = rmid; - list_for_each_entry(event, head, hw.cqm_group_entry) - event->hw.cqm_rmid = rmid; - - raw_spin_unlock_irq(&cache_lock); - - return old_rmid; -} - -/* - * If we fail to assign a new RMID for intel_cqm_rotation_rmid because - * cachelines are still tagged with RMIDs in limbo, we progressively - * increment the threshold until we find an RMID in limbo with <= - * __intel_cqm_threshold lines tagged. This is designed to mitigate the - * problem where cachelines tagged with an RMID are not steadily being - * evicted. - * - * On successful rotations we decrease the threshold back towards zero. - * - * __intel_cqm_max_threshold provides an upper bound on the threshold, - * and is measured in bytes because it's exposed to userland. - */ -static unsigned int __intel_cqm_threshold; -static unsigned int __intel_cqm_max_threshold; - -/* - * Test whether an RMID has a zero occupancy value on this cpu. - */ -static void intel_cqm_stable(void *arg) -{ - struct cqm_rmid_entry *entry; - - list_for_each_entry(entry, &cqm_rmid_limbo_lru, list) { - if (entry->state != RMID_AVAILABLE) - break; - - if (__rmid_read(entry->rmid) > __intel_cqm_threshold) - entry->state = RMID_DIRTY; - } -} - -/* - * If we have group events waiting for an RMID that don't conflict with - * events already running, assign @rmid. - */ -static bool intel_cqm_sched_in_event(u32 rmid) -{ - struct perf_event *leader, *event; - - lockdep_assert_held(&cache_mutex); - - leader = list_first_entry(&cache_groups, struct perf_event, - hw.cqm_groups_entry); - event = leader; - - list_for_each_entry_continue(event, &cache_groups, - hw.cqm_groups_entry) { - if (__rmid_valid(event->hw.cqm_rmid)) - continue; - - if (__conflict_event(event, leader)) - continue; - - intel_cqm_xchg_rmid(event, rmid); - return true; - } - - return false; -} - -/* - * Initially use this constant for both the limbo queue time and the - * rotation timer interval, pmu::hrtimer_interval_ms. - * - * They don't need to be the same, but the two are related since if you - * rotate faster than you recycle RMIDs, you may run out of available - * RMIDs. - */ -#define RMID_DEFAULT_QUEUE_TIME 250 /* ms */ - -static unsigned int __rmid_queue_time_ms = RMID_DEFAULT_QUEUE_TIME; - -/* - * intel_cqm_rmid_stabilize - move RMIDs from limbo to free list - * @nr_available: number of freeable RMIDs on the limbo list - * - * Quiescent state; wait for all 'freed' RMIDs to become unused, i.e. no - * cachelines are tagged with those RMIDs. After this we can reuse them - * and know that the current set of active RMIDs is stable. - * - * Return %true or %false depending on whether stabilization needs to be - * reattempted. - * - * If we return %true then @nr_available is updated to indicate the - * number of RMIDs on the limbo list that have been queued for the - * minimum queue time (RMID_AVAILABLE), but whose data occupancy values - * are above __intel_cqm_threshold. - */ -static bool intel_cqm_rmid_stabilize(unsigned int *available) -{ - struct cqm_rmid_entry *entry, *tmp; - - lockdep_assert_held(&cache_mutex); - - *available = 0; - list_for_each_entry(entry, &cqm_rmid_limbo_lru, list) { - unsigned long min_queue_time; - unsigned long now = jiffies; - - /* - * We hold RMIDs placed into limbo for a minimum queue - * time. Before the minimum queue time has elapsed we do - * not recycle RMIDs. - * - * The reasoning is that until a sufficient time has - * passed since we stopped using an RMID, any RMID - * placed onto the limbo list will likely still have - * data tagged in the cache, which means we'll probably - * fail to recycle it anyway. - * - * We can save ourselves an expensive IPI by skipping - * any RMIDs that have not been queued for the minimum - * time. - */ - min_queue_time = entry->queue_time + - msecs_to_jiffies(__rmid_queue_time_ms); - - if (time_after(min_queue_time, now)) - break; - - entry->state = RMID_AVAILABLE; - (*available)++; - } - - /* - * Fast return if none of the RMIDs on the limbo list have been - * sitting on the queue for the minimum queue time. - */ - if (!*available) - return false; - - /* - * Test whether an RMID is free for each package. - */ - on_each_cpu_mask(&cqm_cpumask, intel_cqm_stable, NULL, true); - - list_for_each_entry_safe(entry, tmp, &cqm_rmid_limbo_lru, list) { - /* - * Exhausted all RMIDs that have waited min queue time. - */ - if (entry->state == RMID_YOUNG) - break; - - if (entry->state == RMID_DIRTY) - continue; - - list_del(&entry->list); /* remove from limbo */ - - /* - * The rotation RMID gets priority if it's - * currently invalid. In which case, skip adding - * the RMID to the the free lru. - */ - if (!__rmid_valid(intel_cqm_rotation_rmid)) { - intel_cqm_rotation_rmid = entry->rmid; - continue; - } - - /* - * If we have groups waiting for RMIDs, hand - * them one now provided they don't conflict. - */ - if (intel_cqm_sched_in_event(entry->rmid)) - continue; - - /* - * Otherwise place it onto the free list. - */ - list_add_tail(&entry->list, &cqm_rmid_free_lru); - } - - - return __rmid_valid(intel_cqm_rotation_rmid); -} - -/* - * Pick a victim group and move it to the tail of the group list. - * @next: The first group without an RMID - */ -static void __intel_cqm_pick_and_rotate(struct perf_event *next) -{ - struct perf_event *rotor; - u32 rmid; - - lockdep_assert_held(&cache_mutex); - - rotor = list_first_entry(&cache_groups, struct perf_event, - hw.cqm_groups_entry); - - /* - * The group at the front of the list should always have a valid - * RMID. If it doesn't then no groups have RMIDs assigned and we - * don't need to rotate the list. - */ - if (next == rotor) - return; - - rmid = intel_cqm_xchg_rmid(rotor, INVALID_RMID); - __put_rmid(rmid); - - list_rotate_left(&cache_groups); -} - -/* - * Deallocate the RMIDs from any events that conflict with @event, and - * place them on the back of the group list. - */ -static void intel_cqm_sched_out_conflicting_events(struct perf_event *event) -{ - struct perf_event *group, *g; - u32 rmid; - - lockdep_assert_held(&cache_mutex); - - list_for_each_entry_safe(group, g, &cache_groups, hw.cqm_groups_entry) { - if (group == event) - continue; - - rmid = group->hw.cqm_rmid; - - /* - * Skip events that don't have a valid RMID. - */ - if (!__rmid_valid(rmid)) - continue; - - /* - * No conflict? No problem! Leave the event alone. - */ - if (!__conflict_event(group, event)) - continue; - - intel_cqm_xchg_rmid(group, INVALID_RMID); - __put_rmid(rmid); - } -} - -/* - * Attempt to rotate the groups and assign new RMIDs. - * - * We rotate for two reasons, - * 1. To handle the scheduling of conflicting events - * 2. To recycle RMIDs - * - * Rotating RMIDs is complicated because the hardware doesn't give us - * any clues. - * - * There's problems with the hardware interface; when you change the - * task:RMID map cachelines retain their 'old' tags, giving a skewed - * picture. In order to work around this, we must always keep one free - * RMID - intel_cqm_rotation_rmid. - * - * Rotation works by taking away an RMID from a group (the old RMID), - * and assigning the free RMID to another group (the new RMID). We must - * then wait for the old RMID to not be used (no cachelines tagged). - * This ensure that all cachelines are tagged with 'active' RMIDs. At - * this point we can start reading values for the new RMID and treat the - * old RMID as the free RMID for the next rotation. - * - * Return %true or %false depending on whether we did any rotating. - */ -static bool __intel_cqm_rmid_rotate(void) -{ - struct perf_event *group, *start = NULL; - unsigned int threshold_limit; - unsigned int nr_needed = 0; - unsigned int nr_available; - bool rotated = false; - - mutex_lock(&cache_mutex); - -again: - /* - * Fast path through this function if there are no groups and no - * RMIDs that need cleaning. - */ - if (list_empty(&cache_groups) && list_empty(&cqm_rmid_limbo_lru)) - goto out; - - list_for_each_entry(group, &cache_groups, hw.cqm_groups_entry) { - if (!__rmid_valid(group->hw.cqm_rmid)) { - if (!start) - start = group; - nr_needed++; - } - } - - /* - * We have some event groups, but they all have RMIDs assigned - * and no RMIDs need cleaning. - */ - if (!nr_needed && list_empty(&cqm_rmid_limbo_lru)) - goto out; - - if (!nr_needed) - goto stabilize; - - /* - * We have more event groups without RMIDs than available RMIDs, - * or we have event groups that conflict with the ones currently - * scheduled. - * - * We force deallocate the rmid of the group at the head of - * cache_groups. The first event group without an RMID then gets - * assigned intel_cqm_rotation_rmid. This ensures we always make - * forward progress. - * - * Rotate the cache_groups list so the previous head is now the - * tail. - */ - __intel_cqm_pick_and_rotate(start); - - /* - * If the rotation is going to succeed, reduce the threshold so - * that we don't needlessly reuse dirty RMIDs. - */ - if (__rmid_valid(intel_cqm_rotation_rmid)) { - intel_cqm_xchg_rmid(start, intel_cqm_rotation_rmid); - intel_cqm_rotation_rmid = __get_rmid(); - - intel_cqm_sched_out_conflicting_events(start); - - if (__intel_cqm_threshold) - __intel_cqm_threshold--; - } - - rotated = true; - -stabilize: - /* - * We now need to stablize the RMID we freed above (if any) to - * ensure that the next time we rotate we have an RMID with zero - * occupancy value. - * - * Alternatively, if we didn't need to perform any rotation, - * we'll have a bunch of RMIDs in limbo that need stabilizing. - */ - threshold_limit = __intel_cqm_max_threshold / cqm_l3_scale; - - while (intel_cqm_rmid_stabilize(&nr_available) && - __intel_cqm_threshold < threshold_limit) { - unsigned int steal_limit; - - /* - * Don't spin if nobody is actively waiting for an RMID, - * the rotation worker will be kicked as soon as an - * event needs an RMID anyway. - */ - if (!nr_needed) - break; - - /* Allow max 25% of RMIDs to be in limbo. */ - steal_limit = (cqm_max_rmid + 1) / 4; - - /* - * We failed to stabilize any RMIDs so our rotation - * logic is now stuck. In order to make forward progress - * we have a few options: - * - * 1. rotate ("steal") another RMID - * 2. increase the threshold - * 3. do nothing - * - * We do both of 1. and 2. until we hit the steal limit. - * - * The steal limit prevents all RMIDs ending up on the - * limbo list. This can happen if every RMID has a - * non-zero occupancy above threshold_limit, and the - * occupancy values aren't dropping fast enough. - * - * Note that there is prioritisation at work here - we'd - * rather increase the number of RMIDs on the limbo list - * than increase the threshold, because increasing the - * threshold skews the event data (because we reuse - * dirty RMIDs) - threshold bumps are a last resort. - */ - if (nr_available < steal_limit) - goto again; - - __intel_cqm_threshold++; - } - -out: - mutex_unlock(&cache_mutex); - return rotated; -} - -static void intel_cqm_rmid_rotate(struct work_struct *work); - -static DECLARE_DELAYED_WORK(intel_cqm_rmid_work, intel_cqm_rmid_rotate); - -static struct pmu intel_cqm_pmu; - -static void intel_cqm_rmid_rotate(struct work_struct *work) -{ - unsigned long delay; - - __intel_cqm_rmid_rotate(); - - delay = msecs_to_jiffies(intel_cqm_pmu.hrtimer_interval_ms); - schedule_delayed_work(&intel_cqm_rmid_work, delay); -} - -/* - * Find a group and setup RMID. - * - * If we're part of a group, we use the group's RMID. - */ -static void intel_cqm_setup_event(struct perf_event *event, - struct perf_event **group) -{ - struct perf_event *iter; - bool conflict = false; - u32 rmid; - - list_for_each_entry(iter, &cache_groups, hw.cqm_groups_entry) { - rmid = iter->hw.cqm_rmid; - - if (__match_event(iter, event)) { - /* All tasks in a group share an RMID */ - event->hw.cqm_rmid = rmid; - *group = iter; - return; - } - - /* - * We only care about conflicts for events that are - * actually scheduled in (and hence have a valid RMID). - */ - if (__conflict_event(iter, event) && __rmid_valid(rmid)) - conflict = true; - } - - if (conflict) - rmid = INVALID_RMID; - else - rmid = __get_rmid(); - - event->hw.cqm_rmid = rmid; -} - -static void intel_cqm_event_read(struct perf_event *event) -{ - unsigned long flags; - u32 rmid; - u64 val; - - /* - * Task events are handled by intel_cqm_event_count(). - */ - if (event->cpu == -1) - return; - - raw_spin_lock_irqsave(&cache_lock, flags); - rmid = event->hw.cqm_rmid; - - if (!__rmid_valid(rmid)) - goto out; - - val = __rmid_read(rmid); - - /* - * Ignore this reading on error states and do not update the value. - */ - if (val & (RMID_VAL_ERROR | RMID_VAL_UNAVAIL)) - goto out; - - local64_set(&event->count, val); -out: - raw_spin_unlock_irqrestore(&cache_lock, flags); -} - -static void __intel_cqm_event_count(void *info) -{ - struct rmid_read *rr = info; - u64 val; - - val = __rmid_read(rr->rmid); - - if (val & (RMID_VAL_ERROR | RMID_VAL_UNAVAIL)) - return; - - atomic64_add(val, &rr->value); -} - -static inline bool cqm_group_leader(struct perf_event *event) -{ - return !list_empty(&event->hw.cqm_groups_entry); -} - -static u64 intel_cqm_event_count(struct perf_event *event) -{ - unsigned long flags; - struct rmid_read rr = { - .value = ATOMIC64_INIT(0), - }; - - /* - * We only need to worry about task events. System-wide events - * are handled like usual, i.e. entirely with - * intel_cqm_event_read(). - */ - if (event->cpu != -1) - return __perf_event_count(event); - - /* - * Only the group leader gets to report values. This stops us - * reporting duplicate values to userspace, and gives us a clear - * rule for which task gets to report the values. - * - * Note that it is impossible to attribute these values to - * specific packages - we forfeit that ability when we create - * task events. - */ - if (!cqm_group_leader(event)) - return 0; - - /* - * Getting up-to-date values requires an SMP IPI which is not - * possible if we're being called in interrupt context. Return - * the cached values instead. - */ - if (unlikely(in_interrupt())) - goto out; - - /* - * Notice that we don't perform the reading of an RMID - * atomically, because we can't hold a spin lock across the - * IPIs. - * - * Speculatively perform the read, since @event might be - * assigned a different (possibly invalid) RMID while we're - * busying performing the IPI calls. It's therefore necessary to - * check @event's RMID afterwards, and if it has changed, - * discard the result of the read. - */ - rr.rmid = ACCESS_ONCE(event->hw.cqm_rmid); - - if (!__rmid_valid(rr.rmid)) - goto out; - - on_each_cpu_mask(&cqm_cpumask, __intel_cqm_event_count, &rr, 1); - - raw_spin_lock_irqsave(&cache_lock, flags); - if (event->hw.cqm_rmid == rr.rmid) - local64_set(&event->count, atomic64_read(&rr.value)); - raw_spin_unlock_irqrestore(&cache_lock, flags); -out: - return __perf_event_count(event); -} - -static void intel_cqm_event_start(struct perf_event *event, int mode) -{ - struct intel_pqr_state *state = this_cpu_ptr(&pqr_state); - u32 rmid = event->hw.cqm_rmid; - - if (!(event->hw.cqm_state & PERF_HES_STOPPED)) - return; - - event->hw.cqm_state &= ~PERF_HES_STOPPED; - - if (state->rmid_usecnt++) { - if (!WARN_ON_ONCE(state->rmid != rmid)) - return; - } else { - WARN_ON_ONCE(state->rmid); - } - - state->rmid = rmid; - wrmsr(MSR_IA32_PQR_ASSOC, rmid, state->closid); -} - -static void intel_cqm_event_stop(struct perf_event *event, int mode) -{ - struct intel_pqr_state *state = this_cpu_ptr(&pqr_state); - - if (event->hw.cqm_state & PERF_HES_STOPPED) - return; - - event->hw.cqm_state |= PERF_HES_STOPPED; - - intel_cqm_event_read(event); - - if (!--state->rmid_usecnt) { - state->rmid = 0; - wrmsr(MSR_IA32_PQR_ASSOC, 0, state->closid); - } else { - WARN_ON_ONCE(!state->rmid); - } -} - -static int intel_cqm_event_add(struct perf_event *event, int mode) -{ - unsigned long flags; - u32 rmid; - - raw_spin_lock_irqsave(&cache_lock, flags); - - event->hw.cqm_state = PERF_HES_STOPPED; - rmid = event->hw.cqm_rmid; - - if (__rmid_valid(rmid) && (mode & PERF_EF_START)) - intel_cqm_event_start(event, mode); - - raw_spin_unlock_irqrestore(&cache_lock, flags); - - return 0; -} - -static void intel_cqm_event_destroy(struct perf_event *event) -{ - struct perf_event *group_other = NULL; - - mutex_lock(&cache_mutex); - - /* - * If there's another event in this group... - */ - if (!list_empty(&event->hw.cqm_group_entry)) { - group_other = list_first_entry(&event->hw.cqm_group_entry, - struct perf_event, - hw.cqm_group_entry); - list_del(&event->hw.cqm_group_entry); - } - - /* - * And we're the group leader.. - */ - if (cqm_group_leader(event)) { - /* - * If there was a group_other, make that leader, otherwise - * destroy the group and return the RMID. - */ - if (group_other) { - list_replace(&event->hw.cqm_groups_entry, - &group_other->hw.cqm_groups_entry); - } else { - u32 rmid = event->hw.cqm_rmid; - - if (__rmid_valid(rmid)) - __put_rmid(rmid); - list_del(&event->hw.cqm_groups_entry); - } - } - - mutex_unlock(&cache_mutex); -} - -static int intel_cqm_event_init(struct perf_event *event) -{ - struct perf_event *group = NULL; - bool rotate = false; - - if (event->attr.type != intel_cqm_pmu.type) - return -ENOENT; - - if (event->attr.config & ~QOS_EVENT_MASK) - return -EINVAL; - - /* unsupported modes and filters */ - if (event->attr.exclude_user || - event->attr.exclude_kernel || - event->attr.exclude_hv || - event->attr.exclude_idle || - event->attr.exclude_host || - event->attr.exclude_guest || - event->attr.sample_period) /* no sampling */ - return -EINVAL; - - INIT_LIST_HEAD(&event->hw.cqm_group_entry); - INIT_LIST_HEAD(&event->hw.cqm_groups_entry); - - event->destroy = intel_cqm_event_destroy; - - mutex_lock(&cache_mutex); - - /* Will also set rmid */ - intel_cqm_setup_event(event, &group); - - if (group) { - list_add_tail(&event->hw.cqm_group_entry, - &group->hw.cqm_group_entry); - } else { - list_add_tail(&event->hw.cqm_groups_entry, - &cache_groups); - - /* - * All RMIDs are either in use or have recently been - * used. Kick the rotation worker to clean/free some. - * - * We only do this for the group leader, rather than for - * every event in a group to save on needless work. - */ - if (!__rmid_valid(event->hw.cqm_rmid)) - rotate = true; - } - - mutex_unlock(&cache_mutex); - - if (rotate) - schedule_delayed_work(&intel_cqm_rmid_work, 0); - - return 0; -} - -EVENT_ATTR_STR(llc_occupancy, intel_cqm_llc, "event=0x01"); -EVENT_ATTR_STR(llc_occupancy.per-pkg, intel_cqm_llc_pkg, "1"); -EVENT_ATTR_STR(llc_occupancy.unit, intel_cqm_llc_unit, "Bytes"); -EVENT_ATTR_STR(llc_occupancy.scale, intel_cqm_llc_scale, NULL); -EVENT_ATTR_STR(llc_occupancy.snapshot, intel_cqm_llc_snapshot, "1"); - -static struct attribute *intel_cqm_events_attr[] = { - EVENT_PTR(intel_cqm_llc), - EVENT_PTR(intel_cqm_llc_pkg), - EVENT_PTR(intel_cqm_llc_unit), - EVENT_PTR(intel_cqm_llc_scale), - EVENT_PTR(intel_cqm_llc_snapshot), - NULL, -}; - -static struct attribute_group intel_cqm_events_group = { - .name = "events", - .attrs = intel_cqm_events_attr, -}; - -PMU_FORMAT_ATTR(event, "config:0-7"); -static struct attribute *intel_cqm_formats_attr[] = { - &format_attr_event.attr, - NULL, -}; - -static struct attribute_group intel_cqm_format_group = { - .name = "format", - .attrs = intel_cqm_formats_attr, -}; - -static ssize_t -max_recycle_threshold_show(struct device *dev, struct device_attribute *attr, - char *page) -{ - ssize_t rv; - - mutex_lock(&cache_mutex); - rv = snprintf(page, PAGE_SIZE-1, "%u\n", __intel_cqm_max_threshold); - mutex_unlock(&cache_mutex); - - return rv; -} - -static ssize_t -max_recycle_threshold_store(struct device *dev, - struct device_attribute *attr, - const char *buf, size_t count) -{ - unsigned int bytes, cachelines; - int ret; - - ret = kstrtouint(buf, 0, &bytes); - if (ret) - return ret; - - mutex_lock(&cache_mutex); - - __intel_cqm_max_threshold = bytes; - cachelines = bytes / cqm_l3_scale; - - /* - * The new maximum takes effect immediately. - */ - if (__intel_cqm_threshold > cachelines) - __intel_cqm_threshold = cachelines; - - mutex_unlock(&cache_mutex); - - return count; -} - -static DEVICE_ATTR_RW(max_recycle_threshold); - -static struct attribute *intel_cqm_attrs[] = { - &dev_attr_max_recycle_threshold.attr, - NULL, -}; - -static const struct attribute_group intel_cqm_group = { - .attrs = intel_cqm_attrs, -}; - -static const struct attribute_group *intel_cqm_attr_groups[] = { - &intel_cqm_events_group, - &intel_cqm_format_group, - &intel_cqm_group, - NULL, -}; - -static struct pmu intel_cqm_pmu = { - .hrtimer_interval_ms = RMID_DEFAULT_QUEUE_TIME, - .attr_groups = intel_cqm_attr_groups, - .task_ctx_nr = perf_sw_context, - .event_init = intel_cqm_event_init, - .add = intel_cqm_event_add, - .del = intel_cqm_event_stop, - .start = intel_cqm_event_start, - .stop = intel_cqm_event_stop, - .read = intel_cqm_event_read, - .count = intel_cqm_event_count, -}; - -static inline void cqm_pick_event_reader(int cpu) -{ - int phys_id = topology_physical_package_id(cpu); - int i; - - for_each_cpu(i, &cqm_cpumask) { - if (phys_id == topology_physical_package_id(i)) - return; /* already got reader for this socket */ - } - - cpumask_set_cpu(cpu, &cqm_cpumask); -} - -static void intel_cqm_cpu_starting(unsigned int cpu) -{ - struct intel_pqr_state *state = &per_cpu(pqr_state, cpu); - struct cpuinfo_x86 *c = &cpu_data(cpu); - - state->rmid = 0; - state->closid = 0; - state->rmid_usecnt = 0; - - WARN_ON(c->x86_cache_max_rmid != cqm_max_rmid); - WARN_ON(c->x86_cache_occ_scale != cqm_l3_scale); -} - -static void intel_cqm_cpu_exit(unsigned int cpu) -{ - int phys_id = topology_physical_package_id(cpu); - int i; - - /* - * Is @cpu a designated cqm reader? - */ - if (!cpumask_test_and_clear_cpu(cpu, &cqm_cpumask)) - return; - - for_each_online_cpu(i) { - if (i == cpu) - continue; - - if (phys_id == topology_physical_package_id(i)) { - cpumask_set_cpu(i, &cqm_cpumask); - break; - } - } -} - -static int intel_cqm_cpu_notifier(struct notifier_block *nb, - unsigned long action, void *hcpu) -{ - unsigned int cpu = (unsigned long)hcpu; - - switch (action & ~CPU_TASKS_FROZEN) { - case CPU_DOWN_PREPARE: - intel_cqm_cpu_exit(cpu); - break; - case CPU_STARTING: - intel_cqm_cpu_starting(cpu); - cqm_pick_event_reader(cpu); - break; - } - - return NOTIFY_OK; -} - -static const struct x86_cpu_id intel_cqm_match[] = { - { .vendor = X86_VENDOR_INTEL, .feature = X86_FEATURE_CQM_OCCUP_LLC }, - {} -}; - -static int __init intel_cqm_init(void) -{ - char *str, scale[20]; - int i, cpu, ret; - - if (!x86_match_cpu(intel_cqm_match)) - return -ENODEV; - - cqm_l3_scale = boot_cpu_data.x86_cache_occ_scale; - - /* - * It's possible that not all resources support the same number - * of RMIDs. Instead of making scheduling much more complicated - * (where we have to match a task's RMID to a cpu that supports - * that many RMIDs) just find the minimum RMIDs supported across - * all cpus. - * - * Also, check that the scales match on all cpus. - */ - cpu_notifier_register_begin(); - - for_each_online_cpu(cpu) { - struct cpuinfo_x86 *c = &cpu_data(cpu); - - if (c->x86_cache_max_rmid < cqm_max_rmid) - cqm_max_rmid = c->x86_cache_max_rmid; - - if (c->x86_cache_occ_scale != cqm_l3_scale) { - pr_err("Multiple LLC scale values, disabling\n"); - ret = -EINVAL; - goto out; - } - } - - /* - * A reasonable upper limit on the max threshold is the number - * of lines tagged per RMID if all RMIDs have the same number of - * lines tagged in the LLC. - * - * For a 35MB LLC and 56 RMIDs, this is ~1.8% of the LLC. - */ - __intel_cqm_max_threshold = - boot_cpu_data.x86_cache_size * 1024 / (cqm_max_rmid + 1); - - snprintf(scale, sizeof(scale), "%u", cqm_l3_scale); - str = kstrdup(scale, GFP_KERNEL); - if (!str) { - ret = -ENOMEM; - goto out; - } - - event_attr_intel_cqm_llc_scale.event_str = str; - - ret = intel_cqm_setup_rmid_cache(); - if (ret) - goto out; - - for_each_online_cpu(i) { - intel_cqm_cpu_starting(i); - cqm_pick_event_reader(i); - } - - __perf_cpu_notifier(intel_cqm_cpu_notifier); - - ret = perf_pmu_register(&intel_cqm_pmu, "intel_cqm", -1); - if (ret) - pr_err("Intel CQM perf registration failed: %d\n", ret); - else - pr_info("Intel CQM monitoring enabled\n"); - -out: - cpu_notifier_register_done(); - - return ret; -} -device_initcall(intel_cqm_init); |