linux-stable/drivers/gpu/drm/i915/gt/intel_engine_types.h
Chris Wilson 44d89409a1 drm/i915: Make the semaphore saturation mask global
The idea behind keeping the saturation mask local to a context backfired
spectacularly. The premise with the local mask was that we would be more
proactive in attempting to use semaphores after each time the context
idled, and that all new contexts would attempt to use semaphores
ignoring the current state of the system. This turns out to be horribly
optimistic. If the system state is still oversaturated and the existing
workloads have all stopped using semaphores, the new workloads would
attempt to use semaphores and be deprioritised behind real work. The
new contexts would not switch off using semaphores until their initial
batch of low priority work had completed. Given sufficient backload load
of equal user priority, this would completely starve the new work of any
GPU time.

To compensate, remove the local tracking in favour of keeping it as
global state on the engine -- once the system is saturated and
semaphores are disabled, everyone stops attempting to use semaphores
until the system is idle again. One of the reason for preferring local
context tracking was that it worked with virtual engines, so for
switching to global state we could either do a complete check of all the
virtual siblings or simply disable semaphores for those requests. This
takes the simpler approach of disabling semaphores on virtual engines.

The downside is that the decision that the engine is saturated is a
local measure -- we are only checking whether or not this context was
scheduled in a timely fashion, it may be legitimately delayed due to user
priorities. We still have the same dilemma though, that we do not want
to employ the semaphore poll unless it will be used.

v2: Explain why we need to assume the worst wrt virtual engines.

Fixes: ca6e56f654 ("drm/i915: Disable semaphore busywaits on saturated systems")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Dmitry Rogozhkin <dmitry.v.rogozhkin@intel.com>
Cc: Dmitry Ermilov <dmitry.ermilov@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190618074153.16055-8-chris@chris-wilson.co.uk
2019-06-19 12:10:45 +01:00

568 lines
16 KiB
C

/*
* SPDX-License-Identifier: MIT
*
* Copyright © 2019 Intel Corporation
*/
#ifndef __INTEL_ENGINE_TYPES__
#define __INTEL_ENGINE_TYPES__
#include <linux/hashtable.h>
#include <linux/irq_work.h>
#include <linux/kref.h>
#include <linux/list.h>
#include <linux/llist.h>
#include <linux/types.h>
#include "i915_gem.h"
#include "i915_gem_batch_pool.h"
#include "i915_pmu.h"
#include "i915_priolist_types.h"
#include "i915_selftest.h"
#include "i915_timeline_types.h"
#include "intel_sseu.h"
#include "intel_wakeref.h"
#include "intel_workarounds_types.h"
#define I915_MAX_SLICES 3
#define I915_MAX_SUBSLICES 8
#define I915_CMD_HASH_ORDER 9
struct dma_fence;
struct drm_i915_gem_object;
struct drm_i915_reg_table;
struct i915_gem_context;
struct i915_request;
struct i915_sched_attr;
struct intel_uncore;
typedef u8 intel_engine_mask_t;
#define ALL_ENGINES ((intel_engine_mask_t)~0ul)
struct intel_hw_status_page {
struct i915_vma *vma;
u32 *addr;
};
struct intel_instdone {
u32 instdone;
/* The following exist only in the RCS engine */
u32 slice_common;
u32 sampler[I915_MAX_SLICES][I915_MAX_SUBSLICES];
u32 row[I915_MAX_SLICES][I915_MAX_SUBSLICES];
};
struct intel_engine_hangcheck {
u64 acthd;
u32 last_ring;
u32 last_head;
unsigned long action_timestamp;
struct intel_instdone instdone;
};
struct intel_ring {
struct kref ref;
struct i915_vma *vma;
void *vaddr;
struct i915_timeline *timeline;
struct list_head request_list;
struct list_head active_link;
u32 head;
u32 tail;
u32 emit;
u32 space;
u32 size;
u32 effective_size;
};
/*
* we use a single page to load ctx workarounds so all of these
* values are referred in terms of dwords
*
* struct i915_wa_ctx_bb:
* offset: specifies batch starting position, also helpful in case
* if we want to have multiple batches at different offsets based on
* some criteria. It is not a requirement at the moment but provides
* an option for future use.
* size: size of the batch in DWORDS
*/
struct i915_ctx_workarounds {
struct i915_wa_ctx_bb {
u32 offset;
u32 size;
} indirect_ctx, per_ctx;
struct i915_vma *vma;
};
#define I915_MAX_VCS 4
#define I915_MAX_VECS 2
/*
* Engine IDs definitions.
* Keep instances of the same type engine together.
*/
enum intel_engine_id {
RCS0 = 0,
BCS0,
VCS0,
VCS1,
VCS2,
VCS3,
#define _VCS(n) (VCS0 + (n))
VECS0,
VECS1,
#define _VECS(n) (VECS0 + (n))
I915_NUM_ENGINES
};
struct st_preempt_hang {
struct completion completion;
unsigned int count;
bool inject_hang;
};
/**
* struct intel_engine_execlists - execlist submission queue and port state
*
* The struct intel_engine_execlists represents the combined logical state of
* driver and the hardware state for execlist mode of submission.
*/
struct intel_engine_execlists {
/**
* @tasklet: softirq tasklet for bottom handler
*/
struct tasklet_struct tasklet;
/**
* @default_priolist: priority list for I915_PRIORITY_NORMAL
*/
struct i915_priolist default_priolist;
/**
* @no_priolist: priority lists disabled
*/
bool no_priolist;
/**
* @submit_reg: gen-specific execlist submission register
* set to the ExecList Submission Port (elsp) register pre-Gen11 and to
* the ExecList Submission Queue Contents register array for Gen11+
*/
u32 __iomem *submit_reg;
/**
* @ctrl_reg: the enhanced execlists control register, used to load the
* submit queue on the HW and to request preemptions to idle
*/
u32 __iomem *ctrl_reg;
/**
* @port: execlist port states
*
* For each hardware ELSP (ExecList Submission Port) we keep
* track of the last request and the number of times we submitted
* that port to hw. We then count the number of times the hw reports
* a context completion or preemption. As only one context can
* be active on hw, we limit resubmission of context to port[0]. This
* is called Lite Restore, of the context.
*/
struct execlist_port {
/**
* @request_count: combined request and submission count
*/
struct i915_request *request_count;
#define EXECLIST_COUNT_BITS 2
#define port_request(p) ptr_mask_bits((p)->request_count, EXECLIST_COUNT_BITS)
#define port_count(p) ptr_unmask_bits((p)->request_count, EXECLIST_COUNT_BITS)
#define port_pack(rq, count) ptr_pack_bits(rq, count, EXECLIST_COUNT_BITS)
#define port_unpack(p, count) ptr_unpack_bits((p)->request_count, count, EXECLIST_COUNT_BITS)
#define port_set(p, packed) ((p)->request_count = (packed))
#define port_isset(p) ((p)->request_count)
#define port_index(p, execlists) ((p) - (execlists)->port)
/**
* @context_id: context ID for port
*/
GEM_DEBUG_DECL(u32 context_id);
#define EXECLIST_MAX_PORTS 2
} port[EXECLIST_MAX_PORTS];
/**
* @active: is the HW active? We consider the HW as active after
* submitting any context for execution and until we have seen the
* last context completion event. After that, we do not expect any
* more events until we submit, and so can park the HW.
*
* As we have a small number of different sources from which we feed
* the HW, we track the state of each inside a single bitfield.
*/
unsigned int active;
#define EXECLISTS_ACTIVE_USER 0
#define EXECLISTS_ACTIVE_PREEMPT 1
#define EXECLISTS_ACTIVE_HWACK 2
/**
* @port_mask: number of execlist ports - 1
*/
unsigned int port_mask;
/**
* @queue_priority_hint: Highest pending priority.
*
* When we add requests into the queue, or adjust the priority of
* executing requests, we compute the maximum priority of those
* pending requests. We can then use this value to determine if
* we need to preempt the executing requests to service the queue.
* However, since the we may have recorded the priority of an inflight
* request we wanted to preempt but since completed, at the time of
* dequeuing the priority hint may no longer may match the highest
* available request priority.
*/
int queue_priority_hint;
/**
* @queue: queue of requests, in priority lists
*/
struct rb_root_cached queue;
struct rb_root_cached virtual;
/**
* @csb_write: control register for Context Switch buffer
*
* Note this register may be either mmio or HWSP shadow.
*/
u32 *csb_write;
/**
* @csb_status: status array for Context Switch buffer
*
* Note these register may be either mmio or HWSP shadow.
*/
u32 *csb_status;
/**
* @preempt_complete_status: expected CSB upon completing preemption
*/
u32 preempt_complete_status;
/**
* @csb_size: context status buffer FIFO size
*/
u8 csb_size;
/**
* @csb_head: context status buffer head
*/
u8 csb_head;
I915_SELFTEST_DECLARE(struct st_preempt_hang preempt_hang;)
};
#define INTEL_ENGINE_CS_MAX_NAME 8
struct intel_engine_cs {
struct drm_i915_private *i915;
struct intel_uncore *uncore;
char name[INTEL_ENGINE_CS_MAX_NAME];
enum intel_engine_id id;
unsigned int hw_id;
unsigned int guc_id;
intel_engine_mask_t mask;
u8 uabi_class;
u8 class;
u8 instance;
u32 context_size;
u32 mmio_base;
u32 uabi_capabilities;
struct intel_sseu sseu;
struct intel_ring *buffer;
struct {
spinlock_t lock;
struct list_head requests;
} active;
struct llist_head barrier_tasks;
struct intel_context *kernel_context; /* pinned */
struct intel_context *preempt_context; /* pinned; optional */
intel_engine_mask_t saturated; /* submitting semaphores too late? */
unsigned long serial;
unsigned long wakeref_serial;
struct intel_wakeref wakeref;
struct drm_i915_gem_object *default_state;
void *pinned_default_state;
/* Rather than have every client wait upon all user interrupts,
* with the herd waking after every interrupt and each doing the
* heavyweight seqno dance, we delegate the task (of being the
* bottom-half of the user interrupt) to the first client. After
* every interrupt, we wake up one client, who does the heavyweight
* coherent seqno read and either goes back to sleep (if incomplete),
* or wakes up all the completed clients in parallel, before then
* transferring the bottom-half status to the next client in the queue.
*
* Compared to walking the entire list of waiters in a single dedicated
* bottom-half, we reduce the latency of the first waiter by avoiding
* a context switch, but incur additional coherent seqno reads when
* following the chain of request breadcrumbs. Since it is most likely
* that we have a single client waiting on each seqno, then reducing
* the overhead of waking that client is much preferred.
*/
struct intel_breadcrumbs {
spinlock_t irq_lock;
struct list_head signalers;
struct irq_work irq_work; /* for use from inside irq_lock */
unsigned int irq_enabled;
bool irq_armed;
} breadcrumbs;
struct intel_engine_pmu {
/**
* @enable: Bitmask of enable sample events on this engine.
*
* Bits correspond to sample event types, for instance
* I915_SAMPLE_QUEUED is bit 0 etc.
*/
u32 enable;
/**
* @enable_count: Reference count for the enabled samplers.
*
* Index number corresponds to @enum drm_i915_pmu_engine_sample.
*/
unsigned int enable_count[I915_ENGINE_SAMPLE_COUNT];
/**
* @sample: Counter values for sampling events.
*
* Our internal timer stores the current counters in this field.
*
* Index number corresponds to @enum drm_i915_pmu_engine_sample.
*/
struct i915_pmu_sample sample[I915_ENGINE_SAMPLE_COUNT];
} pmu;
/*
* A pool of objects to use as shadow copies of client batch buffers
* when the command parser is enabled. Prevents the client from
* modifying the batch contents after software parsing.
*/
struct i915_gem_batch_pool batch_pool;
struct intel_hw_status_page status_page;
struct i915_ctx_workarounds wa_ctx;
struct i915_wa_list ctx_wa_list;
struct i915_wa_list wa_list;
struct i915_wa_list whitelist;
u32 irq_keep_mask; /* always keep these interrupts */
u32 irq_enable_mask; /* bitmask to enable ring interrupt */
void (*irq_enable)(struct intel_engine_cs *engine);
void (*irq_disable)(struct intel_engine_cs *engine);
int (*resume)(struct intel_engine_cs *engine);
struct {
void (*prepare)(struct intel_engine_cs *engine);
void (*reset)(struct intel_engine_cs *engine, bool stalled);
void (*finish)(struct intel_engine_cs *engine);
} reset;
void (*park)(struct intel_engine_cs *engine);
void (*unpark)(struct intel_engine_cs *engine);
void (*set_default_submission)(struct intel_engine_cs *engine);
const struct intel_context_ops *cops;
int (*request_alloc)(struct i915_request *rq);
int (*init_context)(struct i915_request *rq);
int (*emit_flush)(struct i915_request *request, u32 mode);
#define EMIT_INVALIDATE BIT(0)
#define EMIT_FLUSH BIT(1)
#define EMIT_BARRIER (EMIT_INVALIDATE | EMIT_FLUSH)
int (*emit_bb_start)(struct i915_request *rq,
u64 offset, u32 length,
unsigned int dispatch_flags);
#define I915_DISPATCH_SECURE BIT(0)
#define I915_DISPATCH_PINNED BIT(1)
int (*emit_init_breadcrumb)(struct i915_request *rq);
u32 *(*emit_fini_breadcrumb)(struct i915_request *rq,
u32 *cs);
unsigned int emit_fini_breadcrumb_dw;
/* Pass the request to the hardware queue (e.g. directly into
* the legacy ringbuffer or to the end of an execlist).
*
* This is called from an atomic context with irqs disabled; must
* be irq safe.
*/
void (*submit_request)(struct i915_request *rq);
/*
* Called on signaling of a SUBMIT_FENCE, passing along the signaling
* request down to the bonded pairs.
*/
void (*bond_execute)(struct i915_request *rq,
struct dma_fence *signal);
/*
* Call when the priority on a request has changed and it and its
* dependencies may need rescheduling. Note the request itself may
* not be ready to run!
*/
void (*schedule)(struct i915_request *request,
const struct i915_sched_attr *attr);
/*
* Cancel all requests on the hardware, or queued for execution.
* This should only cancel the ready requests that have been
* submitted to the engine (via the engine->submit_request callback).
* This is called when marking the device as wedged.
*/
void (*cancel_requests)(struct intel_engine_cs *engine);
void (*destroy)(struct intel_engine_cs *engine);
struct intel_engine_execlists execlists;
/* status_notifier: list of callbacks for context-switch changes */
struct atomic_notifier_head context_status_notifier;
struct intel_engine_hangcheck hangcheck;
#define I915_ENGINE_NEEDS_CMD_PARSER BIT(0)
#define I915_ENGINE_SUPPORTS_STATS BIT(1)
#define I915_ENGINE_HAS_PREEMPTION BIT(2)
#define I915_ENGINE_HAS_SEMAPHORES BIT(3)
#define I915_ENGINE_NEEDS_BREADCRUMB_TASKLET BIT(4)
#define I915_ENGINE_IS_VIRTUAL BIT(5)
unsigned int flags;
/*
* Table of commands the command parser needs to know about
* for this engine.
*/
DECLARE_HASHTABLE(cmd_hash, I915_CMD_HASH_ORDER);
/*
* Table of registers allowed in commands that read/write registers.
*/
const struct drm_i915_reg_table *reg_tables;
int reg_table_count;
/*
* Returns the bitmask for the length field of the specified command.
* Return 0 for an unrecognized/invalid command.
*
* If the command parser finds an entry for a command in the engine's
* cmd_tables, it gets the command's length based on the table entry.
* If not, it calls this function to determine the per-engine length
* field encoding for the command (i.e. different opcode ranges use
* certain bits to encode the command length in the header).
*/
u32 (*get_cmd_length_mask)(u32 cmd_header);
struct {
/**
* @lock: Lock protecting the below fields.
*/
seqlock_t lock;
/**
* @enabled: Reference count indicating number of listeners.
*/
unsigned int enabled;
/**
* @active: Number of contexts currently scheduled in.
*/
unsigned int active;
/**
* @enabled_at: Timestamp when busy stats were enabled.
*/
ktime_t enabled_at;
/**
* @start: Timestamp of the last idle to active transition.
*
* Idle is defined as active == 0, active is active > 0.
*/
ktime_t start;
/**
* @total: Total time this engine was busy.
*
* Accumulated time not counting the most recent block in cases
* where engine is currently busy (active > 0).
*/
ktime_t total;
} stats;
};
static inline bool
intel_engine_needs_cmd_parser(const struct intel_engine_cs *engine)
{
return engine->flags & I915_ENGINE_NEEDS_CMD_PARSER;
}
static inline bool
intel_engine_supports_stats(const struct intel_engine_cs *engine)
{
return engine->flags & I915_ENGINE_SUPPORTS_STATS;
}
static inline bool
intel_engine_has_preemption(const struct intel_engine_cs *engine)
{
return engine->flags & I915_ENGINE_HAS_PREEMPTION;
}
static inline bool
intel_engine_has_semaphores(const struct intel_engine_cs *engine)
{
return engine->flags & I915_ENGINE_HAS_SEMAPHORES;
}
static inline bool
intel_engine_needs_breadcrumb_tasklet(const struct intel_engine_cs *engine)
{
return engine->flags & I915_ENGINE_NEEDS_BREADCRUMB_TASKLET;
}
static inline bool
intel_engine_is_virtual(const struct intel_engine_cs *engine)
{
return engine->flags & I915_ENGINE_IS_VIRTUAL;
}
#define instdone_slice_mask(dev_priv__) \
(IS_GEN(dev_priv__, 7) ? \
1 : RUNTIME_INFO(dev_priv__)->sseu.slice_mask)
#define instdone_subslice_mask(dev_priv__) \
(IS_GEN(dev_priv__, 7) ? \
1 : RUNTIME_INFO(dev_priv__)->sseu.subslice_mask[0])
#define for_each_instdone_slice_subslice(dev_priv__, slice__, subslice__) \
for ((slice__) = 0, (subslice__) = 0; \
(slice__) < I915_MAX_SLICES; \
(subslice__) = ((subslice__) + 1) < I915_MAX_SUBSLICES ? (subslice__) + 1 : 0, \
(slice__) += ((subslice__) == 0)) \
for_each_if((BIT(slice__) & instdone_slice_mask(dev_priv__)) && \
(BIT(subslice__) & instdone_subslice_mask(dev_priv__)))
#endif /* __INTEL_ENGINE_TYPES_H__ */