On 2018-06-11 18:37, Daniele Ceraolo Spurio wrote:
On 25/05/18 11:26, Tomasz Lis wrote:The patch adds support of preempt-to-idle requesting by setting a properbit within Execlist Control Register, and receiving preemption result fromContext Status Buffer.Preemption in previous gens required a special batch buffer to be executed, so the Command Streamer never preempted to idle directly. In Icelake it ispossible, as there is a hardware mechanism to inform the kernel about status of the preemption request. This patch does not cover using the new preemption mechanism when GuC is active. v2: Added needs_preempt_context() change so that it is not created when preempt-to-idle is supported. (Chris) Updated setting HWACK flag so that it is cleared after preempt-to-dle. (Chris, Daniele) Updated to use I915_ENGINE_HAS_PREEMPTION flag. (Chris) v3: Fixed needs_preempt_context() change. (Chris) Merged preemption trigger functions to one. (Chris) Fixed conyext state tonot assume COMPLETED_MASK after preemption, since idle-to-idle case will not have it set. v4: Simplified needs_preempt_context() change. (Daniele) Removed clearing HWACK flag in idle-to-idle preempt. (Daniele) Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx> Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@xxxxxxxxx> Cc: Michal Winiarski <michal.winiarski@xxxxxxxxx> Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxx> Bspec: 18922 Signed-off-by: Tomasz Lis <tomasz.lis@xxxxxxxxx> --- drivers/gpu/drm/i915/i915_drv.h | 2 + drivers/gpu/drm/i915/i915_gem_context.c | 3 +- drivers/gpu/drm/i915/i915_pci.c | 3 +- drivers/gpu/drm/i915/intel_device_info.h | 1 +drivers/gpu/drm/i915/intel_lrc.c | 113 +++++++++++++++++++++----------drivers/gpu/drm/i915/intel_lrc.h | 1 + 6 files changed, 86 insertions(+), 37 deletions(-)diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.hindex 487922f..35eddf7 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h@@ -2534,6 +2534,8 @@ intel_info(const struct drm_i915_private *dev_priv)((dev_priv)->info.has_logical_ring_elsq) #define HAS_LOGICAL_RING_PREEMPTION(dev_priv) \ ((dev_priv)->info.has_logical_ring_preemption) +#define HAS_HW_PREEMPT_TO_IDLE(dev_priv) \ + ((dev_priv)->info.has_hw_preempt_to_idle) #define HAS_EXECLISTS(dev_priv) HAS_LOGICAL_RING_CONTEXTS(dev_priv)diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.cindex 45393f6..341a5ff 100644 --- a/drivers/gpu/drm/i915/i915_gem_context.c +++ b/drivers/gpu/drm/i915/i915_gem_context.c@@ -455,7 +455,8 @@ destroy_kernel_context(struct i915_gem_context **ctxp)static bool needs_preempt_context(struct drm_i915_private *i915) { - return HAS_LOGICAL_RING_PREEMPTION(i915); + return HAS_LOGICAL_RING_PREEMPTION(i915) && + !HAS_HW_PREEMPT_TO_IDLE(i915); } int i915_gem_contexts_init(struct drm_i915_private *dev_priv)diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.cindex 97a91e6a..ee09926 100644 --- a/drivers/gpu/drm/i915/i915_pci.c +++ b/drivers/gpu/drm/i915/i915_pci.c@@ -593,7 +593,8 @@ static const struct intel_device_info intel_cannonlake_info = {GEN(11), \ .ddb_size = 2048, \ .has_csr = 0, \ - .has_logical_ring_elsq = 1 + .has_logical_ring_elsq = 1, \ + .has_hw_preempt_to_idle = 1 static const struct intel_device_info intel_icelake_11_info = { GEN11_FEATURES,diff --git a/drivers/gpu/drm/i915/intel_device_info.h b/drivers/gpu/drm/i915/intel_device_info.hindex 933e316..4eb97b5 100644 --- a/drivers/gpu/drm/i915/intel_device_info.h +++ b/drivers/gpu/drm/i915/intel_device_info.h @@ -98,6 +98,7 @@ enum intel_platform { func(has_logical_ring_contexts); \ func(has_logical_ring_elsq); \ func(has_logical_ring_preemption); \ + func(has_hw_preempt_to_idle); \ func(has_overlay); \ func(has_pooled_eu); \ func(has_psr); \diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.cindex 8a6058b..f95cb37 100644 --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -154,6 +154,7 @@ #define GEN8_CTX_STATUS_ACTIVE_IDLE (1 << 3) #define GEN8_CTX_STATUS_COMPLETE (1 << 4) #define GEN8_CTX_STATUS_LITE_RESTORE (1 << 15) +#define GEN11_CTX_STATUS_PREEMPT_IDLE (1 << 29) #define GEN8_CTX_STATUS_COMPLETED_MASK \ (GEN8_CTX_STATUS_COMPLETE | GEN8_CTX_STATUS_PREEMPTED)@@ -522,31 +523,46 @@ static void port_assign(struct execlist_port *port, struct i915_request *rq)static void inject_preempt_context(struct intel_engine_cs *engine)continuing the discussion from the previous patch, I still think that we should rename this function now that it doesn't inject a context on some gens. A new function name should be relatively trivial to handle from other patch series hitting the area (compared to having a second function).
Ok, will rename it then. What would be the most adequate name? execlist_send_preempt_to_idle()?
{ struct intel_engine_execlists *execlists = &engine->execlists; - struct intel_context *ce = - to_intel_context(engine->i915->preempt_context, engine); - unsigned int n; - - GEM_BUG_ON(execlists->preempt_complete_status != - upper_32_bits(ce->lrc_desc)); - GEM_BUG_ON((ce->lrc_reg_state[CTX_CONTEXT_CONTROL + 1] & - _MASKED_BIT_ENABLE(CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT | - CTX_CTRL_ENGINE_CTX_SAVE_INHIBIT)) != - _MASKED_BIT_ENABLE(CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT | - CTX_CTRL_ENGINE_CTX_SAVE_INHIBIT)); - /* - * Switch to our empty preempt context so - * the state of the GPU is known (idle). - */ GEM_TRACE("%s\n", engine->name); - for (n = execlists_num_ports(execlists); --n; ) - write_desc(execlists, 0, n); + if (HAS_HW_PREEMPT_TO_IDLE(engine->i915)) { + /* + * hardware which HAS_HW_PREEMPT_TO_IDLE(), always also + * HAS_LOGICAL_RING_ELSQ(), so we can assume ctrl_reg is set + */ + GEM_BUG_ON(execlists->ctrl_reg == NULL); - write_desc(execlists, ce->lrc_desc, n); + /* + * If we have hardware preempt-to-idle, we do not need to + * inject any job to the hardware. We only set a flag. + */ + writel(EL_CTRL_PREEMPT_TO_IDLE, execlists->ctrl_reg); + } else { + struct intel_context *ce = + to_intel_context(engine->i915->preempt_context, engine); + unsigned int n; - /* we need to manually load the submit queue */ - if (execlists->ctrl_reg) - writel(EL_CTRL_LOAD, execlists->ctrl_reg); + GEM_BUG_ON(execlists->preempt_complete_status != + upper_32_bits(ce->lrc_desc)); + GEM_BUG_ON((ce->lrc_reg_state[CTX_CONTEXT_CONTROL + 1] & + _MASKED_BIT_ENABLE(CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT | + CTX_CTRL_ENGINE_CTX_SAVE_INHIBIT)) != + _MASKED_BIT_ENABLE(CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT | + CTX_CTRL_ENGINE_CTX_SAVE_INHIBIT)); + + /* + * Switch to our empty preempt context so + * the state of the GPU is known (idle). + */ + for (n = execlists_num_ports(execlists); --n; ) + write_desc(execlists, 0, n); + + write_desc(execlists, ce->lrc_desc, n); + + /* we need to manually load the submit queue */ + if (execlists->ctrl_reg) + writel(EL_CTRL_LOAD, execlists->ctrl_reg); + } execlists_clear_active(execlists, EXECLISTS_ACTIVE_HWACK); execlists_set_active(execlists, EXECLISTS_ACTIVE_PREEMPT);@@ -1031,22 +1047,48 @@ static void process_csb(struct intel_engine_cs *engine)status, buf[2*head + 1], execlists->active); - if (status & (GEN8_CTX_STATUS_IDLE_ACTIVE | - GEN8_CTX_STATUS_PREEMPTED)) - execlists_set_active(execlists, - EXECLISTS_ACTIVE_HWACK); - if (status & GEN8_CTX_STATUS_ACTIVE_IDLE) - execlists_clear_active(execlists, - EXECLISTS_ACTIVE_HWACK); + /* + * Check if preempted from idle to idle directly. + * The STATUS_IDLE_ACTIVE flag is used to mark + * such transition. + */ + if ((status & GEN8_CTX_STATUS_IDLE_ACTIVE) && + (status & GEN11_CTX_STATUS_PREEMPT_IDLE)) { + + /* Cannot be waiting for HWACK while HW is idle */This comment does not match the check, since if the EXECLISTS_ACTIVE_HWACK is set it means we've received the hw ack, not that we're waiting for it. Personally I would just remove the BUG_ON since we don't really care about the value of HWACK as long as EXECLISTS_ACTIVE_PREEMPT is set, as the latter ensures us we're not going to submit work until the whole preempt process is complete. A BUG_ON for EXECLISTS_ACTIVE_PREEMPT is already in complete_preempt_context so we're covered on that side.
Will remove.
With the 2 minor comments addressed: Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@xxxxxxxxx> Daniele+ GEM_BUG_ON(execlists_is_active(execlists, + EXECLISTS_ACTIVE_HWACK)); - if (!(status & GEN8_CTX_STATUS_COMPLETED_MASK)) - continue; + /* + * We could not have COMPLETED anything + * if we were idle before preemption. + */ + GEM_BUG_ON(status & GEN8_CTX_STATUS_COMPLETED_MASK); + } else { + if (status & (GEN8_CTX_STATUS_IDLE_ACTIVE | + GEN8_CTX_STATUS_PREEMPTED)) + execlists_set_active(execlists, + EXECLISTS_ACTIVE_HWACK); + + if (status & GEN8_CTX_STATUS_ACTIVE_IDLE) + execlists_clear_active(execlists, + EXECLISTS_ACTIVE_HWACK); + + if (!(status & GEN8_CTX_STATUS_COMPLETED_MASK)) + continue; + + /* We should never get a COMPLETED | IDLE_ACTIVE! */ + GEM_BUG_ON(status & GEN8_CTX_STATUS_IDLE_ACTIVE); + } - /* We should never get a COMPLETED | IDLE_ACTIVE! */ - GEM_BUG_ON(status & GEN8_CTX_STATUS_IDLE_ACTIVE); - if (status & GEN8_CTX_STATUS_COMPLETE &&- buf[2*head + 1] == execlists->preempt_complete_status) {+ /* + * Check if preempted to real idle, either directly or + * the preemptive context already finished executing + */ + if ((status & GEN11_CTX_STATUS_PREEMPT_IDLE) || + (status & GEN8_CTX_STATUS_COMPLETE &&+ buf[2*head + 1] == execlists->preempt_complete_status)) {GEM_TRACE("%s preempt-idle\n", engine->name); complete_preempt_context(execlists); continue;@@ -2337,7 +2379,8 @@ static void execlists_set_default_submission(struct intel_engine_cs *engine)engine->unpark = NULL; engine->flags |= I915_ENGINE_SUPPORTS_STATS; - if (engine->i915->preempt_context) + if (engine->i915->preempt_context || + HAS_HW_PREEMPT_TO_IDLE(engine->i915)) engine->flags |= I915_ENGINE_HAS_PREEMPTION; engine->i915->caps.scheduler =diff --git a/drivers/gpu/drm/i915/intel_lrc.h b/drivers/gpu/drm/i915/intel_lrc.hindex 1593194..3249e9b 100644 --- a/drivers/gpu/drm/i915/intel_lrc.h +++ b/drivers/gpu/drm/i915/intel_lrc.h @@ -45,6 +45,7 @@#define RING_EXECLIST_SQ_CONTENTS(engine) _MMIO((engine)->mmio_base + 0x510) #define RING_EXECLIST_CONTROL(engine) _MMIO((engine)->mmio_base + 0x550)#define EL_CTRL_LOAD (1 << 0) +#define EL_CTRL_PREEMPT_TO_IDLE (1 << 1)/* The docs specify that the write pointer wraps around after 5h, "After status * is written out to the last available status QW at offset 5h, this pointer
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