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From:   Scott Branden <scott.branden@broadcom.com>
To:     Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Scott Branden <scott.branden@broadcom.com>,
        Desmond Yan <desmond.yan@broadcom.com>
Cc:     Kees Cook <keescook@chromium.org>, linux-kernel@vger.kernel.org,
        bcm-kernel-feedback-list@broadcom.com,
        Olof Johansson <olof@lixom.net>
Subject: [PATCH v6 11/14] misc: bcm-vk: add BCM_VK_QSTATS
Date:   Fri,  2 Oct 2020 14:23:24 -0700
Message-Id: <20201002212327.18393-12-scott.branden@broadcom.com>
In-Reply-To: <20201002212327.18393-1-scott.branden@broadcom.com>
References: <20201002212327.18393-1-scott.branden@broadcom.com>
Precedence: bulk

Add BCM_VK_QSTATS Kconfig option to allow for enabling debug VK
queue statistics.

These statistics keep track of max, abs_max, and average for the
messages queues.

Co-developed-by: Desmond Yan <desmond.yan@broadcom.com>
Signed-off-by: Desmond Yan <desmond.yan@broadcom.com>
Signed-off-by: Scott Branden <scott.branden@broadcom.com>
---
 drivers/misc/bcm-vk/Kconfig      | 14 +++++++++
 drivers/misc/bcm-vk/bcm_vk_dev.c |  9 ++++++
 drivers/misc/bcm-vk/bcm_vk_msg.c | 52 +++++++++++++++++++++++++++++++-
 drivers/misc/bcm-vk/bcm_vk_msg.h | 12 ++++++++
 4 files changed, 86 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/bcm-vk/Kconfig b/drivers/misc/bcm-vk/Kconfig
index 2272e47655ed..a3a020b19e3b 100644
--- a/drivers/misc/bcm-vk/Kconfig
+++ b/drivers/misc/bcm-vk/Kconfig
@@ -13,3 +13,17 @@ config BCM_VK
 	  accelerators via /dev/bcm-vk.N devices.
 
 	  If unsure, say N.
+
+if BCM_VK
+
+config BCM_VK_QSTATS
+	bool "VK Queue Statistics"
+	help
+	  Turn on to enable Queue Statistics.
+	  These are useful for debugging purposes.
+	  Some performance loss by enabling this debug config.
+	  For properly operating PCIe hardware no need to enable this.
+
+	  If unsure, say N.
+
+endif
diff --git a/drivers/misc/bcm-vk/bcm_vk_dev.c b/drivers/misc/bcm-vk/bcm_vk_dev.c
index 718badb53100..6c2370723e0a 100644
--- a/drivers/misc/bcm-vk/bcm_vk_dev.c
+++ b/drivers/misc/bcm-vk/bcm_vk_dev.c
@@ -1097,6 +1097,15 @@ static int bcm_vk_trigger_reset(struct bcm_vk *vk)
 	vkwrite32(vk, 0, BAR_0, BAR_INTF_VER);
 	memset(&vk->host_alert, 0, sizeof(vk->host_alert));
 	memset(&vk->peer_alert, 0, sizeof(vk->peer_alert));
+#if defined(CONFIG_BCM_VK_QSTATS)
+	/* clear qstats */
+	for (i = 0; i < VK_MSGQ_MAX_NR; i++) {
+		memset(&vk->to_v_msg_chan.qstats[i].qcnts, 0,
+		       sizeof(vk->to_v_msg_chan.qstats[i].qcnts));
+		memset(&vk->to_h_msg_chan.qstats[i].qcnts, 0,
+		       sizeof(vk->to_h_msg_chan.qstats[i].qcnts));
+	}
+#endif
 	/* clear 4096 bits of bitmap */
 	bitmap_clear(vk->bmap, 0, VK_MSG_ID_BITMAP_SIZE);
 
diff --git a/drivers/misc/bcm-vk/bcm_vk_msg.c b/drivers/misc/bcm-vk/bcm_vk_msg.c
index e31d41400199..6ba0a7a94dcc 100644
--- a/drivers/misc/bcm-vk/bcm_vk_msg.c
+++ b/drivers/misc/bcm-vk/bcm_vk_msg.c
@@ -91,6 +91,44 @@ u32 msgq_avail_space(const struct bcm_vk_msgq __iomem *msgq,
 	return (qinfo->q_size - msgq_occupied(msgq, qinfo) - 1);
 }
 
+#if defined(CONFIG_BCM_VK_QSTATS)
+
+/* Use default value of 20000 rd/wr per update */
+#if !defined(BCM_VK_QSTATS_ACC_CNT)
+#define BCM_VK_QSTATS_ACC_CNT 20000
+#endif
+
+static void bcm_vk_update_qstats(struct bcm_vk *vk,
+				 const char *tag,
+				 struct bcm_vk_qstats *qstats,
+				 u32 occupancy)
+{
+	struct bcm_vk_qs_cnts *qcnts = &qstats->qcnts;
+
+	if (occupancy > qcnts->max_occ) {
+		qcnts->max_occ = occupancy;
+		if (occupancy > qcnts->max_abs)
+			qcnts->max_abs = occupancy;
+	}
+
+	qcnts->acc_sum += occupancy;
+	if (++qcnts->cnt >= BCM_VK_QSTATS_ACC_CNT) {
+		/* log average and clear counters */
+		dev_dbg(&vk->pdev->dev,
+			"%s[%d]: Max: [%3d/%3d] Acc %d num %d, Aver %d\n",
+			tag, qstats->q_num,
+			qcnts->max_occ, qcnts->max_abs,
+			qcnts->acc_sum,
+			qcnts->cnt,
+			qcnts->acc_sum / qcnts->cnt);
+
+		qcnts->cnt = 0;
+		qcnts->max_occ = 0;
+		qcnts->acc_sum = 0;
+	}
+}
+#endif
+
 /* number of retries when enqueue message fails before returning EAGAIN */
 #define BCM_VK_H2VK_ENQ_RETRY 10
 #define BCM_VK_H2VK_ENQ_RETRY_DELAY_MS 50
@@ -495,8 +533,12 @@ static int bcm_vk_msg_chan_init(struct bcm_vk_msg_chan *chan)
 
 	mutex_init(&chan->msgq_mutex);
 	spin_lock_init(&chan->pendq_lock);
-	for (i = 0; i < VK_MSGQ_MAX_NR; i++)
+	for (i = 0; i < VK_MSGQ_MAX_NR; i++) {
 		INIT_LIST_HEAD(&chan->pendq[i]);
+#if defined(CONFIG_BCM_VK_QSTATS)
+		chan->qstats[i].q_num = i;
+#endif
+	}
 
 	return 0;
 }
@@ -605,6 +647,10 @@ static int bcm_to_v_msg_enqueue(struct bcm_vk *vk, struct bcm_vk_wkent *entry)
 
 	avail = msgq_avail_space(msgq, qinfo);
 
+#if defined(CONFIG_BCM_VK_QSTATS)
+	bcm_vk_update_qstats(vk, "to_v", &chan->qstats[q_num],
+			     qinfo->q_size - avail);
+#endif
 	/* if not enough space, return EAGAIN and let app handles it */
 	retry = 0;
 	while ((avail < entry->to_v_blks) &&
@@ -818,6 +864,10 @@ s32 bcm_to_h_msg_dequeue(struct bcm_vk *vk)
 				goto idx_err;
 			}
 
+#if defined(CONFIG_BCM_VK_QSTATS)
+			bcm_vk_update_qstats(vk, "to_h", &chan->qstats[q_num],
+					     msgq_occupied(msgq, qinfo));
+#endif
 			num_blks = src_size + 1;
 			data = kzalloc(num_blks * VK_MSGQ_BLK_SIZE, GFP_KERNEL);
 			if (data) {
diff --git a/drivers/misc/bcm-vk/bcm_vk_msg.h b/drivers/misc/bcm-vk/bcm_vk_msg.h
index 637c5d662eb7..d00d9707bd01 100644
--- a/drivers/misc/bcm-vk/bcm_vk_msg.h
+++ b/drivers/misc/bcm-vk/bcm_vk_msg.h
@@ -125,6 +125,14 @@ struct bcm_vk_qs_cnts {
 	u32 max_abs; /* the abs max since reset */
 };
 
+#if defined(CONFIG_BCM_VK_QSTATS)
+/* stats structure */
+struct bcm_vk_qstats {
+	u32 q_num;
+	struct bcm_vk_qs_cnts qcnts;
+};
+#endif
+
 /* control channel structure for either to_v or to_h communication */
 struct bcm_vk_msg_chan {
 	u32 q_nr;
@@ -138,6 +146,10 @@ struct bcm_vk_msg_chan {
 	struct list_head pendq[VK_MSGQ_MAX_NR];
 	/* static queue info from the sync */
 	struct bcm_vk_sync_qinfo sync_qinfo[VK_MSGQ_MAX_NR];
+#if defined(CONFIG_BCM_VK_QSTATS)
+	/* qstats */
+	struct bcm_vk_qstats qstats[VK_MSGQ_MAX_NR];
+#endif
 };
 
 /* total number of supported ctx, 32 ctx each for 5 components */
-- 
2.17.1