From a6111f7b6604e6cf98856839b56a2ae436fc0bab Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Tue, 7 Apr 2015 16:21:02 +0100 Subject: [PATCH] drm/i915: Reduce locking in execlist command submission This eliminates six needless spin lock/unlock pairs when writing out ELSP. v2: Respin with my preferred colour. v3: Mostly back to the original colour Signed-off-by: Tvrtko Ursulin [v1] Signed-off-by: Chris Wilson Cc: Daniel Vetter Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_drv.h | 18 ++++++ drivers/gpu/drm/i915/intel_lrc.c | 16 ++--- drivers/gpu/drm/i915/intel_uncore.c | 98 ++++++++++++++++++++++------- 3 files changed, 103 insertions(+), 29 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index b6750751bb93..0ddf6831a321 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -2537,6 +2537,13 @@ void intel_uncore_forcewake_get(struct drm_i915_private *dev_priv, enum forcewake_domains domains); void intel_uncore_forcewake_put(struct drm_i915_private *dev_priv, enum forcewake_domains domains); +/* Like above but the caller must manage the uncore.lock itself. + * Must be used with I915_READ_FW and friends. + */ +void intel_uncore_forcewake_get__locked(struct drm_i915_private *dev_priv, + enum forcewake_domains domains); +void intel_uncore_forcewake_put__locked(struct drm_i915_private *dev_priv, + enum forcewake_domains domains); void assert_forcewakes_inactive(struct drm_i915_private *dev_priv); static inline bool intel_vgpu_active(struct drm_device *dev) { @@ -3229,6 +3236,17 @@ int intel_freq_opcode(struct drm_i915_private *dev_priv, int val); #define POSTING_READ(reg) (void)I915_READ_NOTRACE(reg) #define POSTING_READ16(reg) (void)I915_READ16_NOTRACE(reg) +/* These are untraced mmio-accessors that are only valid to be used inside + * criticial sections inside IRQ handlers where forcewake is explicitly + * controlled. + * Think twice, and think again, before using these. + * Note: Should only be used between intel_uncore_forcewake_irqlock() and + * intel_uncore_forcewake_irqunlock(). + */ +#define I915_READ_FW(reg__) readl(dev_priv->regs + (reg__)) +#define I915_WRITE_FW(reg__, val__) writel(val__, dev_priv->regs + (reg__)) +#define POSTING_READ_FW(reg__) (void)I915_READ_FW(reg__) + /* "Broadcast RGB" property */ #define INTEL_BROADCAST_RGB_AUTO 0 #define INTEL_BROADCAST_RGB_FULL 1 diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c index 037e94c5ab42..ed28e7d8adea 100644 --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -315,17 +315,19 @@ static void execlists_elsp_write(struct intel_engine_cs *ring, desc[3] = (u32)(temp >> 32); desc[2] = (u32)temp; - intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL); - I915_WRITE(RING_ELSP(ring), desc[1]); - I915_WRITE(RING_ELSP(ring), desc[0]); - I915_WRITE(RING_ELSP(ring), desc[3]); + spin_lock(&dev_priv->uncore.lock); + intel_uncore_forcewake_get__locked(dev_priv, FORCEWAKE_ALL); + I915_WRITE_FW(RING_ELSP(ring), desc[1]); + I915_WRITE_FW(RING_ELSP(ring), desc[0]); + I915_WRITE_FW(RING_ELSP(ring), desc[3]); /* The context is automatically loaded after the following */ - I915_WRITE(RING_ELSP(ring), desc[2]); + I915_WRITE_FW(RING_ELSP(ring), desc[2]); /* ELSP is a wo register, so use another nearby reg for posting instead */ - POSTING_READ(RING_EXECLIST_STATUS(ring)); - intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL); + POSTING_READ_FW(RING_EXECLIST_STATUS(ring)); + intel_uncore_forcewake_put__locked(dev_priv, FORCEWAKE_ALL); + spin_unlock(&dev_priv->uncore.lock); } static int execlists_update_context(struct drm_i915_gem_object *ctx_obj, diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c index ab5cc94588e1..d96d15faf268 100644 --- a/drivers/gpu/drm/i915/intel_uncore.c +++ b/drivers/gpu/drm/i915/intel_uncore.c @@ -375,6 +375,26 @@ void intel_uncore_sanitize(struct drm_device *dev) intel_disable_gt_powersave(dev); } +static void __intel_uncore_forcewake_get(struct drm_i915_private *dev_priv, + enum forcewake_domains fw_domains) +{ + struct intel_uncore_forcewake_domain *domain; + enum forcewake_domain_id id; + + if (!dev_priv->uncore.funcs.force_wake_get) + return; + + fw_domains &= dev_priv->uncore.fw_domains; + + for_each_fw_domain_mask(domain, fw_domains, dev_priv, id) { + if (domain->wake_count++) + fw_domains &= ~(1 << id); + } + + if (fw_domains) + dev_priv->uncore.funcs.force_wake_get(dev_priv, fw_domains); +} + /** * intel_uncore_forcewake_get - grab forcewake domain references * @dev_priv: i915 device instance @@ -392,41 +412,39 @@ void intel_uncore_forcewake_get(struct drm_i915_private *dev_priv, enum forcewake_domains fw_domains) { unsigned long irqflags; - struct intel_uncore_forcewake_domain *domain; - enum forcewake_domain_id id; if (!dev_priv->uncore.funcs.force_wake_get) return; WARN_ON(dev_priv->pm.suspended); - fw_domains &= dev_priv->uncore.fw_domains; - spin_lock_irqsave(&dev_priv->uncore.lock, irqflags); - - for_each_fw_domain_mask(domain, fw_domains, dev_priv, id) { - if (domain->wake_count++) - fw_domains &= ~(1 << id); - } - - if (fw_domains) - dev_priv->uncore.funcs.force_wake_get(dev_priv, fw_domains); - + __intel_uncore_forcewake_get(dev_priv, fw_domains); spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags); } /** - * intel_uncore_forcewake_put - release a forcewake domain reference + * intel_uncore_forcewake_get__locked - grab forcewake domain references * @dev_priv: i915 device instance - * @fw_domains: forcewake domains to put references + * @fw_domains: forcewake domains to get reference on * - * This function drops the device-level forcewakes for specified - * domains obtained by intel_uncore_forcewake_get(). + * See intel_uncore_forcewake_get(). This variant places the onus + * on the caller to explicitly handle the dev_priv->uncore.lock spinlock. */ -void intel_uncore_forcewake_put(struct drm_i915_private *dev_priv, - enum forcewake_domains fw_domains) +void intel_uncore_forcewake_get__locked(struct drm_i915_private *dev_priv, + enum forcewake_domains fw_domains) +{ + assert_spin_locked(&dev_priv->uncore.lock); + + if (!dev_priv->uncore.funcs.force_wake_get) + return; + + __intel_uncore_forcewake_get(dev_priv, fw_domains); +} + +static void __intel_uncore_forcewake_put(struct drm_i915_private *dev_priv, + enum forcewake_domains fw_domains) { - unsigned long irqflags; struct intel_uncore_forcewake_domain *domain; enum forcewake_domain_id id; @@ -435,8 +453,6 @@ void intel_uncore_forcewake_put(struct drm_i915_private *dev_priv, fw_domains &= dev_priv->uncore.fw_domains; - spin_lock_irqsave(&dev_priv->uncore.lock, irqflags); - for_each_fw_domain_mask(domain, fw_domains, dev_priv, id) { if (WARN_ON(domain->wake_count == 0)) continue; @@ -447,10 +463,48 @@ void intel_uncore_forcewake_put(struct drm_i915_private *dev_priv, domain->wake_count++; fw_domain_arm_timer(domain); } +} +/** + * intel_uncore_forcewake_put - release a forcewake domain reference + * @dev_priv: i915 device instance + * @fw_domains: forcewake domains to put references + * + * This function drops the device-level forcewakes for specified + * domains obtained by intel_uncore_forcewake_get(). + */ +void intel_uncore_forcewake_put(struct drm_i915_private *dev_priv, + enum forcewake_domains fw_domains) +{ + unsigned long irqflags; + + if (!dev_priv->uncore.funcs.force_wake_put) + return; + + spin_lock_irqsave(&dev_priv->uncore.lock, irqflags); + __intel_uncore_forcewake_put(dev_priv, fw_domains); spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags); } +/** + * intel_uncore_forcewake_put__locked - grab forcewake domain references + * @dev_priv: i915 device instance + * @fw_domains: forcewake domains to get reference on + * + * See intel_uncore_forcewake_put(). This variant places the onus + * on the caller to explicitly handle the dev_priv->uncore.lock spinlock. + */ +void intel_uncore_forcewake_put__locked(struct drm_i915_private *dev_priv, + enum forcewake_domains fw_domains) +{ + assert_spin_locked(&dev_priv->uncore.lock); + + if (!dev_priv->uncore.funcs.force_wake_put) + return; + + __intel_uncore_forcewake_put(dev_priv, fw_domains); +} + void assert_forcewakes_inactive(struct drm_i915_private *dev_priv) { struct intel_uncore_forcewake_domain *domain; -- 2.20.1