Message-Id: <20220417235517.26865-1-a.fomichev@yadro.com>
Date:   Mon, 18 Apr 2022 02:55:15 +0300
From:   Alexander Fomichev <fomichev.ru@...il.com>
To:     ntb@...ts.linux.dev
Cc:     linux@...ro.com, Alexander Fomichev <fomichev.ru@...il.com>,
        Jon Mason <jdmason@...zu.us>,
        Dave Jiang <dave.jiang@...el.com>,
        Allen Hubbe <allenbh@...il.com>,
        Yang Li <yang.lee@...ux.alibaba.com>,
        Serge Semin <fancer.lancer@...il.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH] ntb_perf: extend with burst/poll/doorbell latency measurement

From: Alexander Fomichev <fomichev.ru@...il.com>

The ntb_perf test provides a tool for NTB hardware performance
evaluation. For software impact elimination the test uses a simple method
(let's call it 'burst' mode), when the local system sends to the remote
system a data set and counts time interval until hardware completion
report, without the remote side confirming, nor data integrity check.
The measured metric is a 'burst' throughput bandwidth of NTB connection.

The proposed change extends ntb_perf with 3 new metrics. The resulting
test is fully backward compatible.

1. Burst latency. It's a delay between start to send 1 byte to the
remote system and hardware readiness to send another byte. The
measurement performed within bandwidth test procedure. The DMA Engine is
off. Data integrity is not checked. This mode can be disabled by
'perf_latency=N' module parameter.

2. Poll latency. It's a delay between start to send 1 byte to the
remote system and receiving the confirmation. The remote system needs to
be run in server mode beforehand. Then the server polls the input buffer
and on receiving data immediately sends confirmation.

3. Doorbell latency. It's a delay between start to ring an NTB doorbell
and receiving the confirmation. The remote system needs to be run in server
mode beforehand. Then the server waits for a doorbell event and immediately
rings self doorbell to confirm.


Signed-off-by: Alexander Fomichev <fomichev.ru@...il.com>
---
 drivers/ntb/test/ntb_perf.c | 820 +++++++++++++++++++++++++++++++++++-
 1 file changed, 804 insertions(+), 16 deletions(-)

diff --git a/drivers/ntb/test/ntb_perf.c b/drivers/ntb/test/ntb_perf.c
index 65e1e5cf1b29..c106c3a5097e 100644
--- a/drivers/ntb/test/ntb_perf.c
+++ b/drivers/ntb/test/ntb_perf.c
@@ -6,6 +6,7 @@
  *
  *   Copyright(c) 2015 Intel Corporation. All rights reserved.
  *   Copyright(c) 2017 T-Platforms. All Rights Reserved.
+ *   Copyright(c) 2022 YADRO. All Rights Reserved.
  *
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of version 2 of the GNU General Public License as
@@ -15,6 +16,7 @@
  *
  *   Copyright(c) 2015 Intel Corporation. All rights reserved.
  *   Copyright(c) 2017 T-Platforms. All Rights Reserved.
+ *   Copyright(c) 2022 YADRO. All Rights Reserved.
  *
  *   Redistribution and use in source and binary forms, with or without
  *   modification, are permitted provided that the following conditions
@@ -65,6 +67,22 @@
  *
  * root@...f# echo 0 > $DBG_DIR/run
  * root@...f# cat $DBG_DIR/run
+ *-----------------------------------------------------------------------------
+ * Eg: start latency test with peer (index 0) poll-waiting and get the metrics
+ *
+ * Server side:
+ * root@...f# echo 0 > $DBG_DIR/poll_latency/run_server
+ * Client side:
+ * root@...f# echo 0 > $DBG_DIR/poll_latency/run_client
+ * root@...f# cat $DBG_DIR/poll_latency/run_client
+ *-----------------------------------------------------------------------------
+ * Eg: start doorbell latency test with peer (index 0) and get the metrics
+ *
+ * Server side:
+ * root@...f# echo 0 > $DBG_DIR/db_latency/run_server
+ * Client side:
+ * root@...f# echo 0 > $DBG_DIR/db_latency/run_client
+ * root@...f# cat $DBG_DIR/db_latency/run_client
  */
 
 #include <linux/init.h>
@@ -76,6 +94,7 @@
 #include <linux/dmaengine.h>
 #include <linux/pci.h>
 #include <linux/ktime.h>
+#include <linux/jiffies.h>
 #include <linux/slab.h>
 #include <linux/delay.h>
 #include <linux/sizes.h>
@@ -85,7 +104,7 @@
 #include <linux/ntb.h>
 
 #define DRIVER_NAME		"ntb_perf"
-#define DRIVER_VERSION		"2.0"
+#define DRIVER_VERSION		"2.2"
 
 MODULE_LICENSE("Dual BSD/GPL");
 MODULE_VERSION(DRIVER_VERSION);
@@ -106,6 +125,9 @@ MODULE_DESCRIPTION("PCIe NTB Performance Measurement Tool");
 
 #define PERF_BUF_LEN 1024
 
+#define LAT_MIN_TRIES	20
+#define RESCHEDULE_RATIO	10000
+
 static unsigned long max_mw_size;
 module_param(max_mw_size, ulong, 0644);
 MODULE_PARM_DESC(max_mw_size, "Upper limit of memory window size");
@@ -122,6 +144,22 @@ static bool use_dma; /* default to 0 */
 module_param(use_dma, bool, 0644);
 MODULE_PARM_DESC(use_dma, "Use DMA engine to measure performance");
 
+static bool perf_latency = true;
+module_param(perf_latency, bool, 0644);
+MODULE_PARM_DESC(perf_latency, "Also measure latency");
+
+static unsigned long lat_time_ms = 1000; /* default 1s */
+module_param(lat_time_ms, ulong, 0644);
+MODULE_PARM_DESC(lat_time_ms, "Time (in ms) to test latency");
+
+static unsigned long lat_timeout_us = 500;
+module_param(lat_timeout_us, ulong, 0644);
+MODULE_PARM_DESC(lat_timeout_us, "Timeout (in us) to wait for server reply");
+
+static unsigned long peer_timeout_s = 60;
+module_param(peer_timeout_s, ulong, 0644);
+MODULE_PARM_DESC(peer_timeout_s, "Timeout (in s) to wait for peer link");
+
 /*==============================================================================
  *                         Perf driver data definition
  *==============================================================================
@@ -138,7 +176,21 @@ enum perf_cmd {
 	PERF_STS_LNKUP = 6, /* link up state flag */
 };
 
+enum run_mode {
+	RUN_PL_CLIENT,
+	RUN_PL_SERVER,
+	RUN_DBL_CLIENT,
+	RUN_DBL_SERVER,
+};
+
 struct perf_ctx;
+struct perf_ext_lat_data;
+
+struct perf_ext_lat_ops {
+	int (*init)(struct perf_ext_lat_data *data);
+	int (*run)(struct perf_ext_lat_data *data);
+	void (*clear)(struct perf_ext_lat_data *data);
+};
 
 struct perf_peer {
 	struct perf_ctx	*perf;
@@ -178,12 +230,30 @@ struct perf_thread {
 	void *src;
 	u64 copied;
 	ktime_t duration;
+	ktime_t latency;
+	u64 tries;
 	int status;
 	struct work_struct work;
 };
 #define to_thread_work(__work) \
 	container_of(__work, struct perf_thread, work)
 
+struct perf_ext_lat_data {
+	struct perf_ctx *perf;
+	ktime_t latency;
+	u64 tries;
+	int status;
+	struct perf_ext_lat_ops ops;
+	struct work_struct work;
+
+	union {
+		void *src;
+		int db;
+	};
+};
+#define to_ext_lat_data(__work) \
+	container_of(__work, struct perf_ext_lat_data, work)
+
 struct perf_ctx {
 	struct ntb_dev *ntb;
 
@@ -192,6 +262,12 @@ struct perf_ctx {
 	int pcnt;
 	struct perf_peer *peers;
 
+	/* Ext latency tests interface */
+	enum run_mode mode;
+	struct perf_ext_lat_data pldata;
+	struct perf_ext_lat_data dbldata;
+	atomic_t running;
+
 	/* Performance measuring work-threads interface */
 	unsigned long busy_flag;
 	wait_queue_head_t twait;
@@ -239,6 +315,8 @@ static struct dentry *perf_dbgfs_topdir;
 
 static struct workqueue_struct *perf_wq __read_mostly;
 
+static const u8 stop_word = 0xFF;
+
 /*==============================================================================
  *                  NTB cross-link commands execution service
  *==============================================================================
@@ -501,6 +579,15 @@ static void perf_link_event(void *ctx)
 	}
 }
 
+static inline void perf_dbl_pong(struct perf_ctx *perf)
+{
+	struct perf_ext_lat_data *data = &perf->dbldata;
+
+	ntb_db_clear(perf->ntb, BIT_ULL(data->db));
+	data->tries++;
+	ntb_peer_db_set(perf->ntb, BIT_ULL(data->db));
+}
+
 static void perf_db_event(void *ctx, int vec)
 {
 	struct perf_ctx *perf = ctx;
@@ -509,7 +596,11 @@ static void perf_db_event(void *ctx, int vec)
 		ntb_db_vector_mask(perf->ntb, vec), ntb_db_read(perf->ntb));
 
 	/* Just receive all available commands */
-	(void)perf_cmd_recv(perf);
+	if (perf->dbldata.db >= 0 &&
+				BIT_ULL(perf->dbldata.db) & ntb_db_read(perf->ntb))
+		perf_dbl_pong(perf);
+	else
+		(void)perf_cmd_recv(perf);
 }
 
 static void perf_msg_event(void *ctx)
@@ -664,6 +755,8 @@ static int perf_init_service(struct perf_ctx *perf)
 		return -EINVAL;
 	}
 
+	perf->dbldata.db = -1;
+
 	if (ntb_msg_count(perf->ntb) >= PERF_MSG_CNT) {
 		perf->cmd_send = perf_msg_cmd_send;
 		perf->cmd_recv = perf_msg_cmd_recv;
@@ -783,7 +876,7 @@ static void perf_dma_copy_callback(void *data)
 }
 
 static int perf_copy_chunk(struct perf_thread *pthr,
-			   void __iomem *dst, void *src, size_t len)
+			   void __iomem *dst, void *src, size_t len, bool use_dma_)
 {
 	struct dma_async_tx_descriptor *tx;
 	struct dmaengine_unmap_data *unmap;
@@ -794,7 +887,7 @@ static int perf_copy_chunk(struct perf_thread *pthr,
 	void __iomem *dst_vaddr;
 	dma_addr_t dst_dma_addr;
 
-	if (!use_dma) {
+	if (!use_dma_) {
 		memcpy_toio(dst, src, len);
 		goto ret_check_tsync;
 	}
@@ -940,7 +1033,7 @@ static int perf_run_test(struct perf_thread *pthr)
 
 	/* Copied field is cleared on test launch stage */
 	while (pthr->copied < total_size) {
-		ret = perf_copy_chunk(pthr, flt_dst, flt_src, chunk_size);
+		ret = perf_copy_chunk(pthr, flt_dst, flt_src, chunk_size, use_dma);
 		if (ret) {
 			dev_err(&perf->ntb->dev, "%d: Got error %d on test\n",
 				pthr->tidx, ret);
@@ -1018,6 +1111,65 @@ static void perf_clear_test(struct perf_thread *pthr)
 	kfree(pthr->src);
 }
 
+static int perf_run_latency(struct perf_thread *pthr)
+{
+	struct perf_peer *peer = pthr->perf->test_peer;
+	struct ntb_dev *ntb = pthr->perf->ntb;
+	void *flt_src;
+	void __iomem *flt_dst, *bnd_dst;
+	int ret;
+	u64 stop_at = ktime_get_real_fast_ns() + lat_time_ms * NSEC_PER_MSEC;
+
+	pthr->tries = 0;
+	pthr->latency = ktime_get();
+	flt_src = pthr->src;
+	flt_dst = peer->outbuf;
+	bnd_dst = peer->outbuf + peer->outbuf_size;
+
+	while (ktime_get_real_fast_ns() < stop_at) {
+		ret = perf_copy_chunk(pthr, flt_dst, flt_src, 1, false);
+		if (ret) {
+			dev_err(&ntb->dev, "%d: Latency testing error %d\n",
+				pthr->tidx, ret);
+			pthr->latency = ktime_set(0, 0);
+			return ret;
+		}
+
+		pthr->tries++;
+		flt_dst++;
+		flt_src++;
+
+		if (flt_dst >= bnd_dst || flt_dst < peer->outbuf) {
+			flt_dst = peer->outbuf;
+			flt_src = pthr->src;
+		}
+
+		/* Avoid processor soft lock-ups */
+		if (!(pthr->tries % RESCHEDULE_RATIO))
+			schedule();
+	}
+
+	/* Stop timer */
+	pthr->latency = ktime_sub(ktime_get(), pthr->latency);
+
+	if (pthr->tries < LAT_MIN_TRIES) {
+		dev_err(&ntb->dev, "%d: Too few steps to measure Latency. "
+				"Increase test time\n", pthr->tidx);
+		pthr->latency = ktime_set(0, 0);
+		return -EINVAL;
+	}
+
+	dev_dbg(&ntb->dev, "%d: made %llu tries, lasted %llu usecs\n",
+		pthr->tidx, pthr->tries, ktime_to_us(pthr->latency));
+
+	pthr->latency = ns_to_ktime(ktime_divns(pthr->latency, pthr->tries));
+
+	dev_dbg(&ntb->dev, "%d: latency %llu us (%llu ns)\n", pthr->tidx,
+		ktime_to_us(pthr->latency), ktime_to_ns(pthr->latency));
+
+	return 0;
+}
+
 static void perf_thread_work(struct work_struct *work)
 {
 	struct perf_thread *pthr = to_thread_work(work);
@@ -1043,11 +1195,280 @@ static void perf_thread_work(struct work_struct *work)
 	}
 
 	pthr->status = perf_sync_test(pthr);
+	if (pthr->status)
+		goto err_clear_test;
+
+	if (perf_latency)
+		pthr->status = perf_run_latency(pthr);
 
 err_clear_test:
 	perf_clear_test(pthr);
 }
 
+static int perf_init_pl(struct perf_ext_lat_data *pldata)
+{
+	struct perf_ctx *perf = pldata->perf;
+	struct perf_peer *peer = perf->test_peer;
+	u8 *bp;
+
+	pldata->src = kmalloc_node(peer->outbuf_size, GFP_KERNEL,
+				dev_to_node(&perf->ntb->dev));
+	if (!pldata->src)
+		return -ENOMEM;
+
+	/*
+	 * Prepare random data to send, guaranteed exclusion of 0x00 (unreceived)
+	 * and 0xFF (stop_word)
+	 */
+	get_random_bytes(pldata->src, peer->outbuf_size);
+	for (bp = pldata->src; bp < (u8 *) pldata->src + peer->outbuf_size; bp++)
+		while (*bp == 0 || *bp == stop_word)
+			*bp = (u8)get_random_int();
+
+	memset(peer->inbuf, 0, peer->inbuf_size);
+
+	return 0;
+}
+
+static int perf_poll_peer_reply(volatile u8 *cur)
+{
+	u64 wait_till = ktime_get_real_fast_ns() + lat_timeout_us * NSEC_PER_USEC;
+
+	while (ktime_get_real_fast_ns() < wait_till) {
+		if (*cur == stop_word) {
+			*cur = 0;
+			return 1;
+		}
+		if (*cur != 0) {
+			*cur = 0;
+			return 0;
+		}
+	}
+	return -EINTR;
+}
+
+static int perf_run_pl_client(struct perf_ext_lat_data *pldata)
+{
+	struct perf_ctx *perf = pldata->perf;
+	struct perf_peer *peer = perf->test_peer;
+	struct ntb_dev *ntb = perf->ntb;
+	void *src = pldata->src;
+	int ret;
+	u64 stop_at = ktime_get_real_fast_ns() + lat_time_ms * NSEC_PER_MSEC;
+
+	dev_dbg(&ntb->dev, "poll_lat: client started.\n");
+
+	pldata->tries = 0;
+	pldata->latency = ktime_get();
+
+	while (ktime_get_real_fast_ns() < stop_at) {
+		memcpy_toio(peer->outbuf, src, 1);
+
+		/* Avoid processor soft lock-ups */
+		schedule();
+
+		ret = perf_poll_peer_reply(peer->inbuf);
+		if (ret < 0) {
+			dev_err(&ntb->dev, "Timeout waiting for peer reply on poll latency\n");
+			pldata->latency = ktime_set(0, 0);
+			return -EINTR;
+		} else if (ret == 1) {
+			dev_warn(&ntb->dev, "Server terminated on poll latency, stopping\n");
+			break;
+		} else if (!atomic_read(&perf->running)) {
+			dev_err(&ntb->dev, "Poll latency client terminated\n");
+			return -EINTR;
+		}
+
+		pldata->tries++;
+		src++;
+
+		if (src >= pldata->src + peer->outbuf_size)
+			src = pldata->src;
+	}
+
+	/* Stop timer */
+	pldata->latency = ktime_sub(ktime_get(), pldata->latency);
+	/* Send stop to peer */
+	memcpy_toio(peer->outbuf, &stop_word, 1);
+
+	if (pldata->tries < LAT_MIN_TRIES) {
+		dev_err(&ntb->dev, "Too few steps to measure poll Latency. "
+				"Increase test time\n");
+		pldata->latency = ktime_set(0, 0);
+		return -EINVAL;
+	}
+
+	dev_dbg(&ntb->dev, "poll_lat: made %llu tries, lasted %llu usecs\n",
+		pldata->tries, ktime_to_us(pldata->latency));
+
+	pldata->latency = ns_to_ktime(ktime_divns(pldata->latency, pldata->tries));
+
+	dev_dbg(&ntb->dev, "poll_lat: latency %llu us (%llu ns)\n",
+		ktime_to_us(pldata->latency), ktime_to_ns(pldata->latency));
+
+	return 0;
+}
+
+static int perf_run_pl_server(struct perf_ext_lat_data *pldata)
+{
+	struct perf_ctx *perf = pldata->perf;
+	struct perf_peer *peer = perf->test_peer;
+	struct ntb_dev *ntb = perf->ntb;
+	void *src = pldata->src;
+	int ret = 0;
+
+	dev_dbg(&ntb->dev, "poll_lat: server started.\n");
+
+	pldata->tries = 0;
+
+	while (ret != 1 && atomic_read(&perf->running)) {
+		ret = perf_poll_peer_reply(peer->inbuf);
+		if (!ret) {
+			/* Pong to client */
+			memcpy_toio(peer->outbuf, src++, 1);
+			if (src >= pldata->src + peer->outbuf_size)
+				src = pldata->src;
+
+			pldata->tries++;
+		}
+
+		/* Avoid processor soft lock-ups */
+		schedule();
+	}
+
+	if (pldata->tries < LAT_MIN_TRIES)
+		dev_warn(&ntb->dev, "Poll latency test terminated too early. "
+				"Increase client's test time\n");
+
+	dev_dbg(&ntb->dev, "poll_lat: server stopped, had responded %llu times\n",
+		pldata->tries);
+
+	return atomic_read(&perf->running) ? -ENODATA : -EINTR;
+}
+
+static void perf_clear_pl(struct perf_ext_lat_data *pldata)
+{
+	struct perf_ctx *perf = pldata->perf;
+	struct perf_peer *peer = perf->test_peer;
+
+	memset(peer->inbuf, stop_word, 1);
+	atomic_set(&perf->running, 0);
+	wake_up(&perf->twait);
+	kfree(pldata->src);
+}
+
+static struct perf_ext_lat_ops perf_pl_client_ops = {
+	.init = perf_init_pl,
+	.run = perf_run_pl_client,
+	.clear = perf_clear_pl
+};
+
+static struct perf_ext_lat_ops perf_pl_server_ops = {
+	.init = perf_init_pl,
+	.run = perf_run_pl_server,
+	.clear = perf_clear_pl
+};
+
+static int perf_init_dbl(struct perf_ext_lat_data *data)
+{
+	struct perf_ctx *perf = data->perf;
+
+	data->db = get_bitmask_order(ntb_db_valid_mask(perf->ntb)) - 1;
+	dev_dbg(&perf->ntb->dev, "DB bit for latency test: %d\n", data->db);
+
+	if (data->db <= perf->gidx) {
+		dev_err(&perf->ntb->dev, "No spare DoorBell found\n");
+		data->db = -1;
+		return -ENOSPC;
+	}
+
+	return ntb_db_clear_mask(perf->ntb, BIT_ULL(data->db));
+}
+
+static int perf_run_dbl_client(struct perf_ext_lat_data *data)
+{
+	struct perf_ctx *perf = data->perf;
+	struct ntb_dev *ntb = perf->ntb;
+	u64 stop_at = ktime_get_real_fast_ns() + lat_time_ms * NSEC_PER_MSEC;
+
+	dev_dbg(&ntb->dev, "db_lat: client started.\n");
+
+	data->tries = 0;
+	data->latency = ktime_get();
+
+	if (ntb_peer_db_set(perf->ntb, BIT_ULL(data->db)))
+		return -EIO;
+
+	while (ktime_get_real_fast_ns() < stop_at) {
+		/* Avoid processor soft lock-ups */
+		schedule();
+
+		if (!atomic_read(&perf->running)) {
+			dev_err(&ntb->dev, "DoorBell latency client terminated\n");
+			return -EINTR;
+		}
+	}
+
+	/* Stop timer */
+	data->latency = ktime_sub(ktime_get(), data->latency);
+
+	if (data->tries < LAT_MIN_TRIES) {
+		dev_err(&ntb->dev, "Too few steps to measure poll Latency. "
+				   "Increase test time\n");
+		data->latency = ktime_set(0, 0);
+		return -EINVAL;
+	}
+
+	dev_dbg(&ntb->dev, "db_lat: made %llu tries, lasted %llu usecs\n",
+		data->tries, ktime_to_us(data->latency));
+
+	data->latency = ns_to_ktime(ktime_divns(data->latency, data->tries));
+
+	dev_dbg(&ntb->dev, "db_lat: latency %llu us (%llu ns)\n",
+		ktime_to_us(data->latency), ktime_to_ns(data->latency));
+
+	return 0;
+}
+
+static void perf_clear_dbl(struct perf_ext_lat_data *data)
+{
+	struct perf_ctx *perf = data->perf;
+
+	data->db = -1;
+	ntb_db_set_mask(perf->ntb, BIT_ULL(data->db));
+	atomic_set(&perf->running, 0);
+	wake_up(&perf->twait);
+}
+
+static struct perf_ext_lat_ops perf_dbl_client_ops = {
+	.init = perf_init_dbl,
+	.run = perf_run_dbl_client,
+	.clear = perf_clear_dbl
+};
+
+static void perf_ext_lat_work(struct work_struct *work)
+{
+	struct perf_ext_lat_data *data = to_ext_lat_data(work);
+
+	if (!data->ops.init || !data->ops.init || !data->ops.init) {
+		struct perf_ctx *perf = data->perf;
+
+		data->status = -EFAULT;
+		atomic_set(&perf->running, 0);
+		wake_up(&perf->twait);
+		return;
+	}
+
+	data->status = data->ops.init(data);
+	if (data->status)
+		return;
+
+	data->status = data->ops.run(data);
+
+	data->ops.clear(data);
+}
+
 static int perf_set_tcnt(struct perf_ctx *perf, u8 tcnt)
 {
 	if (tcnt == 0 || tcnt > MAX_THREADS_CNT)
@@ -1068,7 +1489,10 @@ static void perf_terminate_test(struct perf_ctx *perf)
 	int tidx;
 
 	atomic_set(&perf->tsync, -1);
+	atomic_set(&perf->running, 0);
 	wake_up(&perf->twait);
+	cancel_work_sync(&perf->pldata.work);
+	cancel_work_sync(&perf->dbldata.work);
 
 	for (tidx = 0; tidx < MAX_THREADS_CNT; tidx++) {
 		wake_up(&perf->threads[tidx].dma_wait);
@@ -1082,9 +1506,10 @@ static int perf_submit_test(struct perf_peer *peer)
 	struct perf_thread *pthr;
 	int tidx, ret;
 
-	ret = wait_for_completion_interruptible(&peer->init_comp);
-	if (ret < 0)
-		return ret;
+	ret = wait_for_completion_interruptible_timeout(&peer->init_comp,
+			msecs_to_jiffies(peer_timeout_s * 1000));
+	if (ret <= 0)
+		return ret ? ret : -ETIMEDOUT;
 
 	if (test_and_set_bit_lock(0, &perf->busy_flag))
 		return -EBUSY;
@@ -1114,6 +1539,63 @@ static int perf_submit_test(struct perf_peer *peer)
 	return ret;
 }
 
+static int perf_submit_ext_lat(struct perf_peer *peer)
+{
+	struct perf_ctx *perf = peer->perf;
+	int ret;
+
+	ret = wait_for_completion_interruptible_timeout(&peer->init_comp,
+			msecs_to_jiffies(peer_timeout_s * 1000));
+	if (ret <= 0)
+		return ret ? ret : -ETIMEDOUT;
+
+	if (test_and_set_bit_lock(0, &perf->busy_flag))
+		return -EBUSY;
+
+	perf->test_peer = peer;
+	atomic_set(&perf->running, 1);
+	perf->pldata.status = -ENODATA;
+	perf->pldata.tries = 0;
+	perf->pldata.latency = ktime_set(0, 0);
+	perf->dbldata.status = -ENODATA;
+	perf->dbldata.tries = 0;
+	perf->dbldata.latency = ktime_set(0, 0);
+
+	switch (perf->mode) {
+	case RUN_PL_SERVER:
+		perf->pldata.ops = perf_pl_server_ops;
+		(void)queue_work(perf_wq, &perf->pldata.work);
+		break;
+	case RUN_PL_CLIENT:
+		perf->pldata.ops = perf_pl_client_ops;
+		(void)queue_work(perf_wq, &perf->pldata.work);
+		break;
+	case RUN_DBL_SERVER:
+		ret = perf_init_dbl(&perf->dbldata);
+		dev_dbg(&perf->ntb->dev, "db_lat: server started.\n");
+		goto submit_exit;
+	case RUN_DBL_CLIENT:
+		perf->dbldata.ops = perf_dbl_client_ops;
+		(void)queue_work(perf_wq, &perf->dbldata.work);
+		break;
+	default:
+		ret = -EINVAL;
+		goto submit_exit;
+	}
+
+	ret = wait_event_interruptible(perf->twait,
+				       !atomic_read(&perf->running));
+	if (ret == -ERESTARTSYS) {
+		perf_terminate_test(perf);
+		ret = -EINTR;
+	}
+
+submit_exit:
+	clear_bit_unlock(0, &perf->busy_flag);
+
+	return ret;
+}
+
 static int perf_read_stats(struct perf_ctx *perf, char *buf,
 			   size_t size, ssize_t *pos)
 {
@@ -1142,6 +1624,18 @@ static int perf_read_stats(struct perf_ctx *perf, char *buf,
 			"%d: copied %llu bytes in %llu usecs, %llu MBytes/s\n",
 			tidx, pthr->copied, ktime_to_us(pthr->duration),
 			div64_u64(pthr->copied, ktime_to_us(pthr->duration)));
+
+		if (perf_latency && ktime_compare(pthr->latency, ktime_set(0, 0))) {
+			if (ktime_to_us(pthr->latency) < 10) {
+				(*pos) += scnprintf(buf + *pos, size - *pos,
+						"%d: latency %llu ns\n",
+						tidx, ktime_to_ns(pthr->latency));
+			} else {
+				(*pos) += scnprintf(buf + *pos, size - *pos,
+						"%d: latency %llu us\n",
+						tidx, ktime_to_us(pthr->latency));
+			}
+		}
 	}
 
 	clear_bit_unlock(0, &perf->busy_flag);
@@ -1149,7 +1643,7 @@ static int perf_read_stats(struct perf_ctx *perf, char *buf,
 	return 0;
 }
 
-static void perf_init_threads(struct perf_ctx *perf)
+static void perf_init_workers(struct perf_ctx *perf)
 {
 	struct perf_thread *pthr;
 	int tidx;
@@ -1158,6 +1652,14 @@ static void perf_init_threads(struct perf_ctx *perf)
 	perf->test_peer = &perf->peers[0];
 	init_waitqueue_head(&perf->twait);
 
+	perf->pldata.perf = perf;
+	INIT_WORK(&perf->pldata.work, perf_ext_lat_work);
+	perf->pldata.status = -ENODATA;
+
+	perf->dbldata.perf = perf;
+	INIT_WORK(&perf->dbldata.work, perf_ext_lat_work);
+	perf->dbldata.status = -ENODATA;
+
 	for (tidx = 0; tidx < MAX_THREADS_CNT; tidx++) {
 		pthr = &perf->threads[tidx];
 
@@ -1169,7 +1671,7 @@ static void perf_init_threads(struct perf_ctx *perf)
 	}
 }
 
-static void perf_clear_threads(struct perf_ctx *perf)
+static void perf_clear_workers(struct perf_ctx *perf)
 {
 	perf_terminate_test(perf);
 }
@@ -1313,6 +1815,193 @@ static const struct file_operations perf_dbgfs_run = {
 	.write = perf_dbgfs_write_run
 };
 
+static ssize_t perf_dbgfs_read_run_pl(struct file *filep, char __user *ubuf,
+				   size_t fsize, loff_t *offp)
+{
+	struct perf_ctx *perf = filep->private_data;
+	ssize_t ret;
+	ssize_t pos = 0;
+	ssize_t size = PERF_BUF_LEN;
+	char *buf;
+
+	if (test_and_set_bit_lock(0, &perf->busy_flag))
+		return -EBUSY;
+
+	buf = kmalloc(size, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	pos += scnprintf(buf + pos, size - pos,
+		"    Peer %d test statistics:\n", perf->test_peer->pidx);
+
+	if (perf->pldata.status != -ENODATA) {
+		if (perf->pldata.status) {
+			pos += scnprintf(buf + pos, size - pos,
+				"poll latency: error status %d\n", perf->pldata.status);
+		} else {
+			if (ktime_to_us(perf->pldata.latency) < 10) {
+				pos += scnprintf(buf + pos, size - pos,
+						"poll latency %llu ns\n",
+						ktime_to_ns(perf->pldata.latency));
+			} else {
+				pos += scnprintf(buf + pos, size - pos,
+						"poll latency %llu us\n",
+						ktime_to_us(perf->pldata.latency));
+			}
+		}
+	} else {
+		pos += scnprintf(buf + pos, size - pos, "Test did not run\n");
+	}
+
+	ret = simple_read_from_buffer(ubuf, fsize, offp, buf, pos);
+
+	kfree(buf);
+
+	clear_bit_unlock(0, &perf->busy_flag);
+
+	return ret;
+}
+
+static ssize_t perf_dbgfs_write_run_ext(struct file *filep, const char __user *ubuf,
+					size_t size, loff_t *offp, enum run_mode mode)
+{
+	struct perf_ctx *perf = filep->private_data;
+	struct ntb_dev *ntb = perf->ntb;
+	struct perf_peer *peer;
+	int pidx, ret;
+
+	ret = kstrtoint_from_user(ubuf, size, 0, &pidx);
+	if (ret)
+		return ret;
+
+	if (pidx < 0) {
+		switch (mode) {
+		case RUN_PL_SERVER:
+			dev_dbg(&ntb->dev, "poll_lat: kill server\n");
+			if (test_bit(0, &perf->busy_flag)) {
+				peer = perf->test_peer;
+				/* Send stop to client */
+				memcpy_toio(peer->outbuf, &stop_word, 1);
+			}
+			perf_terminate_test(perf);
+			clear_bit_unlock(0, &perf->busy_flag);
+			return size;
+		case RUN_DBL_SERVER:
+			dev_dbg(&ntb->dev, "db_lat: kill server\n");
+			perf_clear_dbl(&perf->dbldata);
+			clear_bit_unlock(0, &perf->busy_flag);
+			return size;
+		default:
+			return -EINVAL;
+		}
+	}
+
+	if (pidx >= perf->pcnt)
+		return -EINVAL;
+
+	peer = &perf->peers[pidx];
+	perf->mode = mode;
+
+	ret = perf_submit_ext_lat(peer);
+
+	return ret ? ret : size;
+}
+
+static ssize_t perf_dbgfs_write_run_pl_client(struct file *filep,
+					const char __user *ubuf, size_t size, loff_t *offp)
+{
+	return perf_dbgfs_write_run_ext(filep, ubuf, size, offp, RUN_PL_CLIENT);
+}
+
+static const struct file_operations perf_dbgfs_run_pl_client = {
+	.open = simple_open,
+	.read = perf_dbgfs_read_run_pl,
+	.write = perf_dbgfs_write_run_pl_client
+};
+
+static ssize_t perf_dbgfs_write_run_pl_server(struct file *filep,
+					const char __user *ubuf, size_t size, loff_t *offp)
+{
+	return perf_dbgfs_write_run_ext(filep, ubuf, size, offp, RUN_PL_SERVER);
+}
+
+static const struct file_operations perf_dbgfs_run_pl_server = {
+	.open = simple_open,
+	.read = perf_dbgfs_read_run_pl,
+	.write = perf_dbgfs_write_run_pl_server
+};
+
+static ssize_t perf_dbgfs_read_run_dbl(struct file *filep, char __user *ubuf,
+				   size_t fsize, loff_t *offp)
+{
+	struct perf_ctx *perf = filep->private_data;
+	ssize_t ret;
+	ssize_t pos = 0;
+	ssize_t size = PERF_BUF_LEN;
+	char *buf;
+
+	if (test_and_set_bit_lock(0, &perf->busy_flag))
+		return -EBUSY;
+
+	buf = kmalloc(size, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	pos += scnprintf(buf + pos, size - pos,
+		"    Peer %d test statistics:\n", perf->test_peer->pidx);
+
+	if (perf->dbldata.status != -ENODATA) {
+		if (perf->dbldata.status) {
+			pos += scnprintf(buf + pos, size - pos,
+				"doorbell latency: error status %d\n", perf->dbldata.status);
+		} else {
+			if (ktime_to_us(perf->dbldata.latency) < 10) {
+				pos += scnprintf(buf + pos, size - pos,
+						"doorbell latency %llu ns\n",
+						ktime_to_ns(perf->dbldata.latency));
+			} else {
+				pos += scnprintf(buf + pos, size - pos,
+						"doorbell latency %llu us\n",
+						ktime_to_us(perf->dbldata.latency));
+			}
+		}
+	} else {
+		pos += scnprintf(buf + pos, size - pos, "Test did not run\n");
+	}
+
+	ret = simple_read_from_buffer(ubuf, fsize, offp, buf, pos);
+
+	kfree(buf);
+
+	clear_bit_unlock(0, &perf->busy_flag);
+
+	return ret;
+}
+
+static ssize_t perf_dbgfs_write_run_dbl_client(struct file *filep,
+					const char __user *ubuf, size_t size, loff_t *offp)
+{
+	return perf_dbgfs_write_run_ext(filep, ubuf, size, offp, RUN_DBL_CLIENT);
+}
+
+static const struct file_operations perf_dbgfs_run_dbl_client = {
+	.open = simple_open,
+	.read = perf_dbgfs_read_run_dbl,
+	.write = perf_dbgfs_write_run_dbl_client
+};
+
+static ssize_t perf_dbgfs_write_run_dbl_server(struct file *filep,
+					const char __user *ubuf, size_t size, loff_t *offp)
+{
+	return perf_dbgfs_write_run_ext(filep, ubuf, size, offp, RUN_DBL_SERVER);
+}
+
+static const struct file_operations perf_dbgfs_run_dbl_server = {
+	.open = simple_open,
+	.read = perf_dbgfs_read_run_dbl,
+	.write = perf_dbgfs_write_run_dbl_server
+};
+
 static ssize_t perf_dbgfs_read_tcnt(struct file *filep, char __user *ubuf,
 				    size_t size, loff_t *offp)
 {
@@ -1344,15 +2033,76 @@ static ssize_t perf_dbgfs_write_tcnt(struct file *filep,
 	return size;
 }
 
+static ssize_t perf_dbgfs_read_lattrs(struct file *filep, char __user *ubuf,
+				    size_t size, loff_t *offp)
+{
+	struct perf_ctx *perf = filep->private_data;
+	char *buf;
+	ssize_t pos, ret;
+	size_t buf_size = min_t(size_t, size, PERF_BUF_LEN);
+	int tidx;
+
+	buf = kmalloc(buf_size, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	pos = scnprintf(buf, buf_size, "    Peer %d latency try count:\n",
+			perf->test_peer->pidx);
+
+	for (tidx = 0; tidx < perf->tcnt; tidx++) {
+		struct perf_thread *pthr = &perf->threads[tidx];
+
+		pos += scnprintf(buf + pos, buf_size - pos,
+				"%d: made %llu tries\n", tidx, pthr->tries);
+	}
+
+	ret = simple_read_from_buffer(ubuf, size, offp, buf, pos);
+
+	kfree(buf);
+
+	return ret;
+}
+
+static ssize_t perf_dbgfs_read_inbuf(struct file *filep, char __user *ubuf,
+					size_t size, loff_t *offp)
+{
+	struct perf_ctx *perf = filep->private_data;
+	char buf[32];
+	ssize_t pos;
+	u64 *value;
+
+	if (!perf->test_peer || !perf->test_peer->inbuf) {
+		pos = scnprintf(buf, sizeof(buf), "NULL\n");
+	} else {
+		value = perf->test_peer->inbuf;
+		pos = scnprintf(buf, sizeof(buf), "0x%llx\n", *value);
+	}
+
+	return simple_read_from_buffer(ubuf, size, offp, buf, pos);
+}
+
 static const struct file_operations perf_dbgfs_tcnt = {
 	.open = simple_open,
 	.read = perf_dbgfs_read_tcnt,
 	.write = perf_dbgfs_write_tcnt
 };
 
+static const struct file_operations perf_dbgfs_lattrs = {
+	.open = simple_open,
+	.read = perf_dbgfs_read_lattrs
+};
+
+static const struct file_operations perf_dbgfs_inbuf = {
+	.open = simple_open,
+	.read = perf_dbgfs_read_inbuf,
+};
+
 static void perf_setup_dbgfs(struct perf_ctx *perf)
 {
 	struct pci_dev *pdev = perf->ntb->pdev;
+	struct dentry *burst_lat_dir;
+	struct dentry *poll_lat_dir;
+	struct dentry *db_lat_dir;
 
 	perf->dbgfs_dir = debugfs_create_dir(pci_name(pdev), perf_dbgfs_topdir);
 	if (!perf->dbgfs_dir) {
@@ -1363,11 +2113,10 @@ static void perf_setup_dbgfs(struct perf_ctx *perf)
 	debugfs_create_file("info", 0600, perf->dbgfs_dir, perf,
 			    &perf_dbgfs_info);
 
-	debugfs_create_file("run", 0600, perf->dbgfs_dir, perf,
-			    &perf_dbgfs_run);
+	debugfs_create_symlink("run", perf->dbgfs_dir, "burst_latency/run");
 
-	debugfs_create_file("threads_count", 0600, perf->dbgfs_dir, perf,
-			    &perf_dbgfs_tcnt);
+	debugfs_create_symlink("threads_count", perf->dbgfs_dir,
+				"burst_latency/threads_count");
 
 	/* They are made read-only for test exec safety and integrity */
 	debugfs_create_u8("chunk_order", 0500, perf->dbgfs_dir, &chunk_order);
@@ -1375,6 +2124,45 @@ static void perf_setup_dbgfs(struct perf_ctx *perf)
 	debugfs_create_u8("total_order", 0500, perf->dbgfs_dir, &total_order);
 
 	debugfs_create_bool("use_dma", 0500, perf->dbgfs_dir, &use_dma);
+
+	debugfs_create_file("inbuf", 0400, perf->dbgfs_dir, perf,
+			    &perf_dbgfs_inbuf);
+
+	/* burst_latency subdir */
+
+	burst_lat_dir = debugfs_create_dir("burst_latency", perf->dbgfs_dir);
+
+	debugfs_create_file("run", 0600, burst_lat_dir, perf, &perf_dbgfs_run);
+
+	debugfs_create_file("threads_count", 0600, burst_lat_dir, perf,
+			    &perf_dbgfs_tcnt);
+
+	debugfs_create_file("tries", 0400, burst_lat_dir, perf,
+			    &perf_dbgfs_lattrs);
+
+	/* poll_latency subdir */
+
+	poll_lat_dir = debugfs_create_dir("poll_latency", perf->dbgfs_dir);
+
+	debugfs_create_file("run_client", 0600, poll_lat_dir, perf,
+			    &perf_dbgfs_run_pl_client);
+
+	debugfs_create_file("run_server", 0600, poll_lat_dir, perf,
+			    &perf_dbgfs_run_pl_server);
+
+	debugfs_create_u64("tries", 0400, poll_lat_dir, &perf->pldata.tries);
+
+	/* db_latency subdir */
+
+	db_lat_dir = debugfs_create_dir("db_latency", perf->dbgfs_dir);
+
+	debugfs_create_file("run_client", 0600, db_lat_dir, perf,
+			    &perf_dbgfs_run_dbl_client);
+
+	debugfs_create_file("run_server", 0600, db_lat_dir, perf,
+			    &perf_dbgfs_run_dbl_server);
+
+	debugfs_create_u64("tries", 0400, db_lat_dir, &perf->dbldata.tries);
 }
 
 static void perf_clear_dbgfs(struct perf_ctx *perf)
@@ -1494,7 +2282,7 @@ static int perf_probe(struct ntb_client *client, struct ntb_dev *ntb)
 	if (ret)
 		return ret;
 
-	perf_init_threads(perf);
+	perf_init_workers(perf);
 
 	ret = perf_init_service(perf);
 	if (ret)
@@ -1517,7 +2305,7 @@ static void perf_remove(struct ntb_client *client, struct ntb_dev *ntb)
 
 	perf_disable_service(perf);
 
-	perf_clear_threads(perf);
+	perf_clear_workers(perf);
 }
 
 static struct ntb_client perf_client = {
-- 
2.17.1

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