From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sender4-pp-f112.zoho.com (sender4-pp-f112.zoho.com [136.143.188.112]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 602B645A285 for ; Wed, 12 Aug 2026 14:08:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.112 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786543699; cv=pass; b=Y4ftUI5J97hxJy83D1iu2RRIp3Yj6pSHZTvSm6iosIJ570a/CMjjQOLRpUbMhIKZvfNtdAdRBiunftqYRo1ygiWIRSoHnvHzrYwHDblx/9+ZpnwjQDkmmz1NyKAFgtfL8TdXLNp+xCDkobBXlHSmKC+1NU8wvmQkRJsstuvpJQw= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786543699; c=relaxed/simple; bh=rdWMIoZhLQBX2qNdm9LG+8j6Mh2YNYotGmPPfapV500=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=i7OOpLo7ADWu658Kv2ItUV8at04AsbYMEhGsWwP/h5a900/V2/wQQ87pLWqcLt2VqIeZELxqg/M4fGQxSHno8nNYH/UVdWGpHGVcm/tUyxZKbhHcRbfaf2vGQZsj/685B+P3BIhSajHLCF1CGhF8EdksCK+7oUx7q+6Sjqkzyiw= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (1024-bit key) header.d=collabora.com header.i=nicolas.frattaroli@collabora.com header.b=WR1pPQD1; arc=pass smtp.client-ip=136.143.188.112 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=collabora.com header.i=nicolas.frattaroli@collabora.com header.b="WR1pPQD1" ARC-Seal: i=1; a=rsa-sha256; t=1786543665; cv=none; d=zohomail.com; s=zohoarc; b=mVuLC0Y1n+VHUgIJe7Ew7Him+6dSZDYpxEIhyulZxQnIUm9IMasPbJyZMdtrVpTaBO7XcVfoHcEuQSzSjQ+iCccAwTzDP5UvniRLLqK1NsYzEHM41bx6K1vYomAHEvUwFFKmSQZX3ub1a4teeWX+p1bNkIq3xsmseKpZRppA7oI= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1786543665; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:Subject:Subject:To:To:Message-Id:Reply-To; bh=I6vWnS1wTCIKEgK1Y1hzrODYhhOal746YWUq+5WuGqI=; b=YlasFehSX8uLWbdL23GZvDW3ypd5d2TANhzghlRGvgGDkCFA4GIzXhevObKV1SahdqLw7G/z91FrhPki7DX3OAs7SLwP5Cd9GSEUWC9T/EBEsxeNvkqZ81ny7154axw+tKZ9wZsd+efPcw1Cmqhk8trwWGynp/tjP2FCv45J+GA= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=collabora.com; spf=pass smtp.mailfrom=nicolas.frattaroli@collabora.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1786543665; s=zohomail; d=collabora.com; i=nicolas.frattaroli@collabora.com; h=From:From:Date:Date:Subject:Subject:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-Id:Message-Id:In-Reply-To:To:To:Cc:Cc:Reply-To; bh=I6vWnS1wTCIKEgK1Y1hzrODYhhOal746YWUq+5WuGqI=; b=WR1pPQD1jUs1gjNa+CgU8+1b9XuEGNoi4eLXFhjoKq4PbLpy2//MQliqBQvOEGU7 GY+qrwXL3OWlJT6tl5kvRwHOVGkrLlbYtPkhs22NVtADmExHOgMygOSelka0XuDmT1Y I1SBXaOjtgNTwzlQeM3dbf22gmqwLPLt8DlR13Ys= Received: by mx.zohomail.com with SMTPS id 1786543662895618.0778032572175; Wed, 12 Aug 2026 07:07:42 -0700 (PDT) From: Nicolas Frattaroli Date: Wed, 12 Aug 2026 16:07:18 +0200 Subject: [PATCH v4 1/3] drm/panthor: Add tracepoint for cache flushing Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260812-panthor-cache-flush-fix-v4-1-751e32901898@collabora.com> References: <20260812-panthor-cache-flush-fix-v4-0-751e32901898@collabora.com> In-Reply-To: <20260812-panthor-cache-flush-fix-v4-0-751e32901898@collabora.com> To: Boris Brezillon , Steven Price , Liviu Dudau , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Grant Likely , Heiko Stuebner Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, kernel@collabora.com, Nicolas Frattaroli X-Mailer: b4 0.15.2 Add a new event tracepoint: gpu_cache_flush to be emitted after a GPU cache flush completes, with duration and return status arguments. This allows debugging the duration a flush takes irrespective of initial function entry lock contention, and communicates information about whether the flush timed out or errored out in other ways, and which caches were flushed. Signed-off-by: Nicolas Frattaroli --- drivers/gpu/drm/panthor/panthor_gpu.c | 26 +++++++++++++++++++++- drivers/gpu/drm/panthor/panthor_trace.h | 38 +++++++++++++++++++++++++++++++++ 2 files changed, 63 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/panthor/panthor_gpu.c b/drivers/gpu/drm/panthor/panthor_gpu.c index c013d6bf9a59..7088371c6d64 100644 --- a/drivers/gpu/drm/panthor/panthor_gpu.c +++ b/drivers/gpu/drm/panthor/panthor_gpu.c @@ -317,6 +317,21 @@ int panthor_gpu_l2_power_on(struct panthor_device *ptdev) return panthor_gpu_power_on(ptdev, L2, 1, 20000); } +static inline void panthor_gpu_emit_flush_caches_tp(struct panthor_device *ptdev, + u64 start, u32 l2, u32 lsc, + u32 other, int ret) +{ + u32 duration; + + if (!tracepoint_enabled(gpu_cache_flush) || !start) + return; + + if (check_sub_overflow(ktime_get_ns(), start, &duration)) + duration = U32_MAX; + + trace_gpu_cache_flush(ptdev->base.dev, l2, lsc, other, duration, ret); +} + /** * panthor_gpu_flush_caches() - Flush caches * @ptdev: Device. @@ -331,12 +346,17 @@ int panthor_gpu_flush_caches(struct panthor_device *ptdev, { struct panthor_gpu *gpu = ptdev->gpu; unsigned long flags; + u64 start = 0; int ret = 0; /* Serialize cache flush operations. */ guard(mutex)(&ptdev->gpu->cache_flush_lock); spin_lock_irqsave(&ptdev->gpu->reqs_lock, flags); + + if (tracepoint_enabled(gpu_cache_flush)) + start = ktime_get_ns(); + if (!(ptdev->gpu->pending_reqs & GPU_IRQ_CLEAN_CACHES_COMPLETED)) { ptdev->gpu->pending_reqs |= GPU_IRQ_CLEAN_CACHES_COMPLETED; gpu_write(gpu->iomem, GPU_CMD, GPU_FLUSH_CACHES(l2, lsc, other)); @@ -345,8 +365,10 @@ int panthor_gpu_flush_caches(struct panthor_device *ptdev, } spin_unlock_irqrestore(&ptdev->gpu->reqs_lock, flags); - if (ret) + if (ret) { + panthor_gpu_emit_flush_caches_tp(ptdev, start, l2, lsc, other, ret); return ret; + } if (!wait_event_timeout(ptdev->gpu->reqs_acked, !(ptdev->gpu->pending_reqs & GPU_IRQ_CLEAN_CACHES_COMPLETED), @@ -360,6 +382,8 @@ int panthor_gpu_flush_caches(struct panthor_device *ptdev, spin_unlock_irqrestore(&ptdev->gpu->reqs_lock, flags); } + panthor_gpu_emit_flush_caches_tp(ptdev, start, l2, lsc, other, ret); + if (ret) { panthor_device_schedule_reset(ptdev); drm_err(&ptdev->base, "Flush caches timeout"); diff --git a/drivers/gpu/drm/panthor/panthor_trace.h b/drivers/gpu/drm/panthor/panthor_trace.h index 6ffeb4fe6599..bd8652549ab4 100644 --- a/drivers/gpu/drm/panthor/panthor_trace.h +++ b/drivers/gpu/drm/panthor/panthor_trace.h @@ -76,6 +76,44 @@ TRACE_EVENT(gpu_job_irq, __entry->events, __entry->duration_ns) ); +/** + * gpu_cache_flush - emitted after cache flush completes + * @dev: pointer to the &struct device, for printing the device name + * @l2: "l2" flush flags + * @lsc: "lsc" flush flags + * @other: "other" flush flags + * @duration_ns: how long the cache flush operation took, in nanoseconds + * @ret: return status, 0 == success, negative errno on error + * + * Begins measuring after any initial lock contention around the locks needed + * for flushing caches, but before the actual cache flush is requested. Stops + * measuring and is emitted after flush operation is over. + */ +TRACE_EVENT(gpu_cache_flush, + TP_PROTO(const struct device *dev, u32 l2, u32 lsc, u32 other, + u32 duration_ns, int ret), + TP_ARGS(dev, l2, lsc, other, duration_ns, ret), + TP_STRUCT__entry( + __string(dev_name, dev_name(dev)) + __field(u32, l2) + __field(u32, lsc) + __field(u32, other) + __field(u32, duration_ns) + __field(int, ret) + ), + TP_fast_assign( + __assign_str(dev_name); + __entry->l2 = l2; + __entry->lsc = lsc; + __entry->other = other; + __entry->duration_ns = duration_ns; + __entry->ret = ret; + ), + TP_printk("%s: l2=0x%x lsc=0x%x other=0x%x duration_ns=%u ret=%d", + __get_str(dev_name), __entry->l2, __entry->lsc, + __entry->other, __entry->duration_ns, __entry->ret) +); + #endif /* __PANTHOR_TRACE_H__ */ #undef TRACE_INCLUDE_PATH -- 2.55.0