From 58223d5b7a5a168eeff5ae7ca2bf85cb185746ca Mon Sep 17 00:00:00 2001
From: Andrew Rybchenko <arybchik@FreeBSD.org>
Date: Thu, 12 Jan 2017 13:00:17 +0000
Subject: [PATCH] sfxge(4): add tunable to configure MAC stats update period

Reviewed by:    philip
Sponsored by:   Solarflare Communications, Inc.
MFC after:      2 days
Differential Revision:  https://reviews.freebsd.org/D9151
---
 share/man/man4/sfxge.4     |  8 ++++++++
 sys/dev/sfxge/sfxge.h      |  1 +
 sys/dev/sfxge/sfxge_port.c | 34 ++++++++++++++++++++++++++++++++--
 3 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/share/man/man4/sfxge.4 b/share/man/man4/sfxge.4
index 9be27e01804..0e33f4b03d8 100644
--- a/share/man/man4/sfxge.4
+++ b/share/man/man4/sfxge.4
@@ -158,6 +158,14 @@ The default for each port will be the value of
 .Va hw.sfxge.mcdi_logging.
 The logging may also be enabled or disabled after the driver is loaded using the sysctl
 .Va dev.sfxge.%d.mcdi_logging.
+.It Va hw.sfxge.stats_update_period_ms
+Period in milliseconds to refresh interface statistics from hardware.
+The accepted range is 0 to 65535, the default is 1000 (1 second).
+Use zero value to disable periodic statistics update.
+Supported on SFN8xxx series adapters with firmware v6.2.1.1033 and later and
+SFN5xxx and SFN6xxx series adapters.
+SFN7xxx series adapters and SFN8xxx series with earlier firmware use a
+fixed 1000 milliseconds statistics update period.
 .El
 .Sh SUPPORT
 For general information and support,
diff --git a/sys/dev/sfxge/sfxge.h b/sys/dev/sfxge/sfxge.h
index 90914dac68f..ed8b49d6fb2 100644
--- a/sys/dev/sfxge/sfxge.h
+++ b/sys/dev/sfxge/sfxge.h
@@ -248,6 +248,7 @@ struct sfxge_port {
 #endif
 	struct sfxge_hw_stats	phy_stats;
 	struct sfxge_hw_stats	mac_stats;
+	uint16_t		stats_update_period_ms;
 	efx_link_mode_t		link_mode;
 	uint8_t			mcast_addrs[EFX_MAC_MULTICAST_LIST_MAX *
 					    EFX_MAC_ADDR_LEN];
diff --git a/sys/dev/sfxge/sfxge_port.c b/sys/dev/sfxge/sfxge_port.c
index cb574f0c910..3585f0d7192 100644
--- a/sys/dev/sfxge/sfxge_port.c
+++ b/sys/dev/sfxge/sfxge_port.c
@@ -43,6 +43,15 @@ __FBSDID("$FreeBSD$");
 
 #include "sfxge.h"
 
+#define	SFXGE_PARAM_STATS_UPDATE_PERIOD_MS \
+	SFXGE_PARAM(stats_update_period_ms)
+static int sfxge_stats_update_period_ms = SFXGE_STATS_UPDATE_PERIOD_MS;
+TUNABLE_INT(SFXGE_PARAM_STATS_UPDATE_PERIOD_MS,
+	    &sfxge_stats_update_period_ms);
+SYSCTL_INT(_hw_sfxge, OID_AUTO, stats_update_period_ms, CTLFLAG_RDTUN,
+	   &sfxge_stats_update_period_ms, 0,
+	   "netstat interface statistics update period in milliseconds");
+
 static int sfxge_phy_cap_mask(struct sfxge_softc *, int, uint32_t *);
 
 static int
@@ -62,7 +71,7 @@ sfxge_mac_stat_update(struct sfxge_softc *sc)
 		goto out;
 	}
 
-	min_ticks = (unsigned int)hz * SFXGE_STATS_UPDATE_PERIOD_MS / 1000;
+	min_ticks = (unsigned int)hz * port->stats_update_period_ms / 1000;
 
 	now = ticks;
 	if ((unsigned int)(now - port->mac_stats.update_time) < min_ticks) {
@@ -515,7 +524,7 @@ sfxge_port_start(struct sfxge_softc *sc)
 
 	/* Update MAC stats by DMA every period */
 	if ((rc = efx_mac_stats_periodic(enp, &port->mac_stats.dma_buf,
-					 SFXGE_STATS_UPDATE_PERIOD_MS,
+					 port->stats_update_period_ms,
 					 B_FALSE)) != 0)
 		goto fail6;
 
@@ -673,6 +682,26 @@ sfxge_port_fini(struct sfxge_softc *sc)
 	port->sc = NULL;
 }
 
+static uint16_t
+sfxge_port_stats_update_period_ms(struct sfxge_softc *sc)
+{
+	int period_ms = sfxge_stats_update_period_ms;
+
+	if (period_ms < 0) {
+		device_printf(sc->dev,
+			"treat negative stats update period %d as 0 (disable)\n",
+			 period_ms);
+		period_ms = 0;
+	} else if (period_ms > UINT16_MAX) {
+		device_printf(sc->dev,
+			"treat too big stats update period %d as %u\n",
+			period_ms, UINT16_MAX);
+		period_ms = UINT16_MAX;
+	}
+
+	return period_ms;
+}
+
 int
 sfxge_port_init(struct sfxge_softc *sc)
 {
@@ -721,6 +750,7 @@ sfxge_port_init(struct sfxge_softc *sc)
 					    M_SFXGE, M_WAITOK | M_ZERO);
 	if ((rc = sfxge_dma_alloc(sc, EFX_MAC_STATS_SIZE, mac_stats_buf)) != 0)
 		goto fail2;
+	port->stats_update_period_ms = sfxge_port_stats_update_period_ms(sc);
 	sfxge_mac_stat_init(sc);
 
 	port->init_state = SFXGE_PORT_INITIALIZED;