From 155e941f49289fe73157f1c9b3c93450a2e40175 Mon Sep 17 00:00:00 2001 From: Robert Bragg Date: Tue, 13 Jun 2017 12:23:05 +0100 Subject: [PATCH] drm/i915/perf: per-gen timebase for checking sample freq An oa_exponent_to_ns() utility and per-gen timebase constants where recently removed when updating the tail pointer race condition WA, and this restores those so we can update the _PROP_OA_EXPONENT validation done in read_properties_unlocked() to not assume we have a 12.5MHz timebase as we did for Haswell. Accordingly the oa_sample_rate_hard_limit value that's referenced by proc_dointvec_minmax defining the absolute limit for the OA sampling frequency is now initialized to (timestamp_frequency / 2) instead of the 6.25MHz constant for Haswell. v2: Specify frequency of 19.2MHz for BXT (Ville) Initialize oa_sample_rate_hard_limit per-gen too (Lionel) Signed-off-by: Robert Bragg Signed-off-by: Lionel Landwerlin Reviewed-by: Matthew Auld Signed-off-by: Ben Widawsky --- drivers/gpu/drm/i915/i915_drv.h | 1 + drivers/gpu/drm/i915/i915_perf.c | 39 +++++++++++++++++++++++--------- 2 files changed, 29 insertions(+), 11 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 101b66b3f86a..975e216f3469 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -2415,6 +2415,7 @@ struct drm_i915_private { bool periodic; int period_exponent; + int timestamp_frequency; int metrics_set; diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c index a6af4d7dc4d6..4d79698685ea 100644 --- a/drivers/gpu/drm/i915/i915_perf.c +++ b/drivers/gpu/drm/i915/i915_perf.c @@ -288,10 +288,12 @@ static u32 i915_perf_stream_paranoid = true; /* For sysctl proc_dointvec_minmax of i915_oa_max_sample_rate * - * 160ns is the smallest sampling period we can theoretically program the OA - * unit with on Haswell, corresponding to 6.25MHz. + * The highest sampling frequency we can theoretically program the OA unit + * with is always half the timestamp frequency: E.g. 6.25Mhz for Haswell. + * + * Initialized just before we register the sysctl parameter. */ -static int oa_sample_rate_hard_limit = 6250000; +static int oa_sample_rate_hard_limit; /* Theoretically we can program the OA unit to sample every 160ns but don't * allow that by default unless root... @@ -2642,6 +2644,12 @@ err: return ret; } +static u64 oa_exponent_to_ns(struct drm_i915_private *dev_priv, int exponent) +{ + return div_u64(1000000000ULL * (2ULL << exponent), + dev_priv->perf.oa.timestamp_frequency); +} + /** * read_properties_unlocked - validate + copy userspace stream open properties * @dev_priv: i915 device instance @@ -2738,16 +2746,13 @@ static int read_properties_unlocked(struct drm_i915_private *dev_priv, } /* Theoretically we can program the OA unit to sample - * every 160ns but don't allow that by default unless - * root. - * - * On Haswell the period is derived from the exponent - * as: - * - * period = 80ns * 2^(exponent + 1) + * e.g. every 160ns for HSW, 167ns for BDW/SKL or 104ns + * for BXT. We don't allow such high sampling + * frequencies by default unless root. */ + BUILD_BUG_ON(sizeof(oa_period) != 8); - oa_period = 80ull * (2ull << value); + oa_period = oa_exponent_to_ns(dev_priv, value); /* This check is primarily to ensure that oa_period <= * UINT32_MAX (before passing to do_div which only @@ -3003,6 +3008,8 @@ void i915_perf_init(struct drm_i915_private *dev_priv) dev_priv->perf.oa.ops.oa_hw_tail_read = gen7_oa_hw_tail_read; + dev_priv->perf.oa.timestamp_frequency = 12500000; + dev_priv->perf.oa.oa_formats = hsw_oa_formats; dev_priv->perf.oa.n_builtin_sets = @@ -3018,6 +3025,9 @@ void i915_perf_init(struct drm_i915_private *dev_priv) if (IS_GEN8(dev_priv)) { dev_priv->perf.oa.ctx_oactxctrl_offset = 0x120; dev_priv->perf.oa.ctx_flexeu0_offset = 0x2ce; + + dev_priv->perf.oa.timestamp_frequency = 12500000; + dev_priv->perf.oa.gen8_valid_ctx_bit = (1<<25); if (IS_BROADWELL(dev_priv)) { @@ -3034,6 +3044,9 @@ void i915_perf_init(struct drm_i915_private *dev_priv) } else if (IS_GEN9(dev_priv)) { dev_priv->perf.oa.ctx_oactxctrl_offset = 0x128; dev_priv->perf.oa.ctx_flexeu0_offset = 0x3de; + + dev_priv->perf.oa.timestamp_frequency = 12000000; + dev_priv->perf.oa.gen8_valid_ctx_bit = (1<<16); if (IS_SKL_GT2(dev_priv)) { @@ -3052,6 +3065,8 @@ void i915_perf_init(struct drm_i915_private *dev_priv) dev_priv->perf.oa.ops.select_metric_set = i915_oa_select_metric_set_sklgt4; } else if (IS_BROXTON(dev_priv)) { + dev_priv->perf.oa.timestamp_frequency = 19200000; + dev_priv->perf.oa.n_builtin_sets = i915_oa_n_builtin_metric_sets_bxt; dev_priv->perf.oa.ops.select_metric_set = @@ -3086,6 +3101,8 @@ void i915_perf_init(struct drm_i915_private *dev_priv) spin_lock_init(&dev_priv->perf.hook_lock); spin_lock_init(&dev_priv->perf.oa.oa_buffer.ptr_lock); + oa_sample_rate_hard_limit = + dev_priv->perf.oa.timestamp_frequency / 2; dev_priv->perf.sysctl_header = register_sysctl_table(dev_root); dev_priv->perf.initialized = true; -- 2.39.5