Author: np
Date: Fri Sep 12 05:25:56 2014
New Revision: 271450
URL: http://svnweb.freebsd.org/changeset/base/271450
Log:
cxgbe(4): knobs to enable/disable PAUSE frame based flow control.
MFC after: 1 week
Modified:
head/share/man/man4/cxgbe.4
head/sys/dev/cxgbe/t4_main.c
Modified: head/share/man/man4/cxgbe.4
==============================================================================
--- head/share/man/man4/cxgbe.4 Fri Sep 12 04:15:35 2014 (r271449)
+++ head/share/man/man4/cxgbe.4 Fri Sep 12 05:25:56 2014 (r271450)
@@ -240,8 +240,19 @@ The default is -1 which lets the driver
Controls the hardware response to congestion.
-1 disables congestion feedback and is not recommended.
0 instructs the hardware to backpressure its pipeline on congestion.
-This usually results in the port emitting pause frames.
+This usually results in the port emitting PAUSE frames.
1 instructs the hardware to drop frames destined for congested queues.
+.It Va hw.cxgbe.pause_settings
+PAUSE frame settings.
+Bit 0 is rx_pause, bit 1 is tx_pause.
+rx_pause = 1 instructs the hardware to heed incoming PAUSE frames, 0 instructs
+it to ignore them.
+tx_pause = 1 allows the hardware to emit PAUSE frames when its receive FIFO
+reaches a high threshold, 0 prohibits the hardware from emitting PAUSE frames.
+The default is 3 (both rx_pause and tx_pause = 1).
+This tunable establishes the default PAUSE settings for all ports.
+Settings can be displayed and controlled on a per-port basis via the
+dev.cxgbe.X.pause_settings (dev.cxl.X.pause_settings for T5 cards) sysctl.
.It Va hw.cxgbe.buffer_packing
Allow the hardware to deliver multiple frames in the same receive buffer
opportunistically.
Modified: head/sys/dev/cxgbe/t4_main.c
==============================================================================
--- head/sys/dev/cxgbe/t4_main.c Fri Sep 12 04:15:35 2014
(r271449)
+++ head/sys/dev/cxgbe/t4_main.c Fri Sep 12 05:25:56 2014
(r271450)
@@ -281,6 +281,15 @@ static char t4_cfg_file[32] = DEFAULT_CF
TUNABLE_STR("hw.cxgbe.config_file", t4_cfg_file, sizeof(t4_cfg_file));
/*
+ * PAUSE settings (bit 0, 1 = rx_pause, tx_pause respectively).
+ * rx_pause = 1 to heed incoming PAUSE frames, 0 to ignore them.
+ * tx_pause = 1 to emit PAUSE frames when the rx FIFO reaches its high water
+ * mark or when signalled to do so, 0 to never emit PAUSE.
+ */
+static int t4_pause_settings = PAUSE_TX | PAUSE_RX;
+TUNABLE_INT("hw.cxgbe.pause_settings", &t4_pause_settings);
+
+/*
* Firmware auto-install by driver during attach (0, 1, 2 = prohibited,
allowed,
* encouraged respectively).
*/
@@ -393,6 +402,7 @@ static int sysctl_holdoff_tmr_idx(SYSCTL
static int sysctl_holdoff_pktc_idx(SYSCTL_HANDLER_ARGS);
static int sysctl_qsize_rxq(SYSCTL_HANDLER_ARGS);
static int sysctl_qsize_txq(SYSCTL_HANDLER_ARGS);
+static int sysctl_pause_settings(SYSCTL_HANDLER_ARGS);
static int sysctl_handle_t4_reg64(SYSCTL_HANDLER_ARGS);
static int sysctl_temperature(SYSCTL_HANDLER_ARGS);
#ifdef SBUF_DRAIN
@@ -697,6 +707,12 @@ t4_attach(device_t dev)
sc->port[i] = NULL;
goto done;
}
+
+ pi->link_cfg.requested_fc &= ~(PAUSE_TX | PAUSE_RX);
+ pi->link_cfg.requested_fc |= t4_pause_settings;
+ pi->link_cfg.fc &= ~(PAUSE_TX | PAUSE_RX);
+ pi->link_cfg.fc |= t4_pause_settings;
+
rc = -t4_link_start(sc, sc->mbox, pi->tx_chan, &pi->link_cfg);
if (rc != 0) {
device_printf(dev, "port %d l1cfg failed: %d\n", i, rc);
@@ -4771,6 +4787,10 @@ cxgbe_sysctls(struct port_info *pi)
CTLTYPE_INT | CTLFLAG_RW, pi, 0, sysctl_qsize_txq, "I",
"tx queue size");
+ SYSCTL_ADD_PROC(ctx, children, OID_AUTO, "pause_settings",
+ CTLTYPE_STRING | CTLFLAG_RW, pi, PAUSE_TX, sysctl_pause_settings,
+ "A", "PAUSE settings (bit 0 = rx_pause, bit 1 = tx_pause)");
+
/*
* dev.cxgbe.X.stats.
*/
@@ -5152,6 +5172,65 @@ sysctl_qsize_txq(SYSCTL_HANDLER_ARGS)
}
static int
+sysctl_pause_settings(SYSCTL_HANDLER_ARGS)
+{
+ struct port_info *pi = arg1;
+ struct adapter *sc = pi->adapter;
+ struct link_config *lc = &pi->link_cfg;
+ int rc;
+
+ if (req->newptr == NULL) {
+ struct sbuf *sb;
+ static char *bits = "\20\1PAUSE_RX\2PAUSE_TX";
+
+ rc = sysctl_wire_old_buffer(req, 0);
+ if (rc != 0)
+ return(rc);
+
+ sb = sbuf_new_for_sysctl(NULL, NULL, 128, req);
+ if (sb == NULL)
+ return (ENOMEM);
+
+ sbuf_printf(sb, "%b", lc->fc & (PAUSE_TX | PAUSE_RX), bits);
+ rc = sbuf_finish(sb);
+ sbuf_delete(sb);
+ } else {
+ char s[2];
+ int n;
+
+ s[0] = '0' + (lc->requested_fc & (PAUSE_TX | PAUSE_RX));
+ s[1] = 0;
+
+ rc = sysctl_handle_string(oidp, s, sizeof(s), req);
+ if (rc != 0)
+ return(rc);
+
+ if (s[1] != 0)
+ return (EINVAL);
+ if (s[0] < '0' || s[0] > '9')
+ return (EINVAL); /* not a number */
+ n = s[0] - '0';
+ if (n & ~(PAUSE_TX | PAUSE_RX))
+ return (EINVAL); /* some other bit is set too */
+
+ rc = begin_synchronized_op(sc, pi, SLEEP_OK | INTR_OK,
"t4PAUSE");
+ if (rc)
+ return (rc);
+ if ((lc->requested_fc & (PAUSE_TX | PAUSE_RX)) != n) {
+ int link_ok = lc->link_ok;
+
+ lc->requested_fc &= ~(PAUSE_TX | PAUSE_RX);
+ lc->requested_fc |= n;
+ rc = -t4_link_start(sc, sc->mbox, pi->tx_chan, lc);
+ lc->link_ok = link_ok; /* restore */
+ }
+ end_synchronized_op(sc, 0);
+ }
+
+ return (rc);
+}
+
+static int
sysctl_handle_t4_reg64(SYSCTL_HANDLER_ARGS)
{
struct adapter *sc = arg1;
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