From patchwork Wed Sep 20 04:02:11 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Dixit, Ashutosh" X-Patchwork-Id: 13392072 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 51233CE79AC for ; Wed, 20 Sep 2023 04:02:40 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 445A110E43A; Wed, 20 Sep 2023 04:02:36 +0000 (UTC) Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.31]) by gabe.freedesktop.org (Postfix) with ESMTPS id A44F010E424; Wed, 20 Sep 2023 04:02:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1695182553; x=1726718553; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=HGPYiYiQfRFLsrUuXlVIuA304F5GSy2KJSAB0B47n+Q=; b=FIWodon5T3suDH9QQA+JB5jpEB4mnT0jMhgYRrh9MV6dQZJbz/LOpOQN tS/CLeg3Qrac41C4J1wdVH+ObcwbmoBLWm1vM2fgILQcZkhAb9OkLR4jD De7PD//b+fv4T3hVf51X+3JmH8nwyWtojBfrv1E736Sf03Y6h+UgsGk/T X9xe6RHX/0f7ehz0HQrfbANmIsrmHhcy9N5j4vlCNv3OvgFO3ofF2Wrc2 prL4v6FO6AiXHockj8mxuDNBbCqU9k318EUpwSVwKIpLu9CCRJ9vTe7eu /vm4CMeEwA6LvJJiq0guM0SlvuYvjvCkBCVJZ7krjreD7auLuMbJMaZb2 w==; X-IronPort-AV: E=McAfee;i="6600,9927,10838"; a="444209695" X-IronPort-AV: E=Sophos;i="6.02,160,1688454000"; d="scan'208";a="444209695" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Sep 2023 21:02:19 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10838"; a="775822951" X-IronPort-AV: E=Sophos;i="6.02,160,1688454000"; d="scan'208";a="775822951" Received: from orsosgc001.jf.intel.com (HELO unerlige-ril.jf.intel.com) ([10.165.21.138]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Sep 2023 21:02:18 -0700 From: Ashutosh Dixit To: intel-gfx@lists.freedesktop.org Subject: [PATCH] drm/i915/perf: Remove gtt_offset from stream->oa_buffer.head/.tail Date: Tue, 19 Sep 2023 21:02:11 -0700 Message-ID: <20230920040211.2351279-1-ashutosh.dixit@intel.com> X-Mailer: git-send-email 2.41.0 MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: dri-devel@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" There is no reason to add gtt_offset to the cached head/tail pointers stream->oa_buffer.head and stream->oa_buffer.tail. This causes the code to constantly add gtt_offset and subtract gtt_offset and is error prone. It is much simpler to maintain stream->oa_buffer.head and stream->oa_buffer.tail without adding gtt_offset to them and just allow for the gtt_offset when reading/writing from/to HW registers. v2: Minor tweak to commit message due to dropping patch in previous series Signed-off-by: Ashutosh Dixit Reviewed-by: Umesh Nerlige Ramappa --- drivers/gpu/drm/i915/i915_perf.c | 52 ++++++++------------------------ 1 file changed, 13 insertions(+), 39 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c index 018f42fff4cc0..1347e4ec9dd5a 100644 --- a/drivers/gpu/drm/i915/i915_perf.c +++ b/drivers/gpu/drm/i915/i915_perf.c @@ -543,10 +543,9 @@ static bool oa_buffer_check_unlocked(struct i915_perf_stream *stream) { u32 gtt_offset = i915_ggtt_offset(stream->oa_buffer.vma); int report_size = stream->oa_buffer.format->size; - u32 head, tail, read_tail; + u32 tail, hw_tail; unsigned long flags; bool pollin; - u32 hw_tail; u32 partial_report_size; /* We have to consider the (unlikely) possibility that read() errors @@ -556,6 +555,7 @@ static bool oa_buffer_check_unlocked(struct i915_perf_stream *stream) spin_lock_irqsave(&stream->oa_buffer.ptr_lock, flags); hw_tail = stream->perf->ops.oa_hw_tail_read(stream); + hw_tail -= gtt_offset; /* The tail pointer increases in 64 byte increments, not in report_size * steps. Also the report size may not be a power of 2. Compute @@ -567,13 +567,6 @@ static bool oa_buffer_check_unlocked(struct i915_perf_stream *stream) /* Subtract partial amount off the tail */ hw_tail = OA_TAKEN(hw_tail, partial_report_size); - /* NB: The head we observe here might effectively be a little - * out of date. If a read() is in progress, the head could be - * anywhere between this head and stream->oa_buffer.tail. - */ - head = stream->oa_buffer.head - gtt_offset; - read_tail = stream->oa_buffer.tail - gtt_offset; - tail = hw_tail; /* Walk the stream backward until we find a report with report @@ -587,7 +580,7 @@ static bool oa_buffer_check_unlocked(struct i915_perf_stream *stream) * memory in the order they were written to. * If not : (╯°□°）╯︵ ┻━┻ */ - while (OA_TAKEN(tail, read_tail) >= report_size) { + while (OA_TAKEN(tail, stream->oa_buffer.tail) >= report_size) { void *report = stream->oa_buffer.vaddr + tail; if (oa_report_id(stream, report) || @@ -601,9 +594,9 @@ static bool oa_buffer_check_unlocked(struct i915_perf_stream *stream) __ratelimit(&stream->perf->tail_pointer_race)) drm_notice(&stream->uncore->i915->drm, "unlanded report(s) head=0x%x tail=0x%x hw_tail=0x%x\n", - head, tail, hw_tail); + stream->oa_buffer.head, tail, hw_tail); - stream->oa_buffer.tail = gtt_offset + tail; + stream->oa_buffer.tail = tail; pollin = OA_TAKEN(stream->oa_buffer.tail, stream->oa_buffer.head) >= report_size; @@ -753,13 +746,6 @@ static int gen8_append_oa_reports(struct i915_perf_stream *stream, spin_unlock_irqrestore(&stream->oa_buffer.ptr_lock, flags); - /* - * NB: oa_buffer.head/tail include the gtt_offset which we don't want - * while indexing relative to oa_buf_base. - */ - head -= gtt_offset; - tail -= gtt_offset; - /* * An out of bounds or misaligned head or tail pointer implies a driver * bug since we validate + align the tail pointers we read from the @@ -895,9 +881,8 @@ static int gen8_append_oa_reports(struct i915_perf_stream *stream, * We removed the gtt_offset for the copy loop above, indexing * relative to oa_buf_base so put back here... */ - head += gtt_offset; intel_uncore_write(uncore, oaheadptr, - head & GEN12_OAG_OAHEADPTR_MASK); + (head + gtt_offset) & GEN12_OAG_OAHEADPTR_MASK); stream->oa_buffer.head = head; spin_unlock_irqrestore(&stream->oa_buffer.ptr_lock, flags); @@ -1042,12 +1027,6 @@ static int gen7_append_oa_reports(struct i915_perf_stream *stream, spin_unlock_irqrestore(&stream->oa_buffer.ptr_lock, flags); - /* NB: oa_buffer.head/tail include the gtt_offset which we don't want - * while indexing relative to oa_buf_base. - */ - head -= gtt_offset; - tail -= gtt_offset; - /* An out of bounds or misaligned head or tail pointer implies a driver * bug since we validate + align the tail pointers we read from the * hardware and we are in full control of the head pointer which should @@ -1110,13 +1089,8 @@ static int gen7_append_oa_reports(struct i915_perf_stream *stream, if (start_offset != *offset) { spin_lock_irqsave(&stream->oa_buffer.ptr_lock, flags); - /* We removed the gtt_offset for the copy loop above, indexing - * relative to oa_buf_base so put back here... - */ - head += gtt_offset; - intel_uncore_write(uncore, GEN7_OASTATUS2, - (head & GEN7_OASTATUS2_HEAD_MASK) | + ((head + gtt_offset) & GEN7_OASTATUS2_HEAD_MASK) | GEN7_OASTATUS2_MEM_SELECT_GGTT); stream->oa_buffer.head = head; @@ -1704,7 +1678,7 @@ static void gen7_init_oa_buffer(struct i915_perf_stream *stream) */ intel_uncore_write(uncore, GEN7_OASTATUS2, /* head */ gtt_offset | GEN7_OASTATUS2_MEM_SELECT_GGTT); - stream->oa_buffer.head = gtt_offset; + stream->oa_buffer.head = 0; intel_uncore_write(uncore, GEN7_OABUFFER, gtt_offset); @@ -1712,7 +1686,7 @@ static void gen7_init_oa_buffer(struct i915_perf_stream *stream) gtt_offset | OABUFFER_SIZE_16M); /* Mark that we need updated tail pointers to read from... */ - stream->oa_buffer.tail = gtt_offset; + stream->oa_buffer.tail = 0; spin_unlock_irqrestore(&stream->oa_buffer.ptr_lock, flags); @@ -1746,7 +1720,7 @@ static void gen8_init_oa_buffer(struct i915_perf_stream *stream) intel_uncore_write(uncore, GEN8_OASTATUS, 0); intel_uncore_write(uncore, GEN8_OAHEADPTR, gtt_offset); - stream->oa_buffer.head = gtt_offset; + stream->oa_buffer.head = 0; intel_uncore_write(uncore, GEN8_OABUFFER_UDW, 0); @@ -1763,7 +1737,7 @@ static void gen8_init_oa_buffer(struct i915_perf_stream *stream) intel_uncore_write(uncore, GEN8_OATAILPTR, gtt_offset & GEN8_OATAILPTR_MASK); /* Mark that we need updated tail pointers to read from... */ - stream->oa_buffer.tail = gtt_offset; + stream->oa_buffer.tail = 0; /* * Reset state used to recognise context switches, affecting which @@ -1800,7 +1774,7 @@ static void gen12_init_oa_buffer(struct i915_perf_stream *stream) intel_uncore_write(uncore, __oa_regs(stream)->oa_status, 0); intel_uncore_write(uncore, __oa_regs(stream)->oa_head_ptr, gtt_offset & GEN12_OAG_OAHEADPTR_MASK); - stream->oa_buffer.head = gtt_offset; + stream->oa_buffer.head = 0; /* * PRM says: @@ -1816,7 +1790,7 @@ static void gen12_init_oa_buffer(struct i915_perf_stream *stream) gtt_offset & GEN12_OAG_OATAILPTR_MASK); /* Mark that we need updated tail pointers to read from... */ - stream->oa_buffer.tail = gtt_offset; + stream->oa_buffer.tail = 0; /* * Reset state used to recognise context switches, affecting which