wil6210: Tx performance monitoring

For performance monitoring, trace time intervals when Tx vring
is idle/not idle. Use CPU cycle counter for this, because jiffies is
too rough, and other precise time measurement methods involve
overhead while get_cycles() should be fast.
This used to provide some estimation for percentage when Tx vring
was idle, i.e. when hardware is under-utilized.
Estimation is not precise because of many reasons - CPU frequency scaling,
grt_cycles() may be per core etc. But still, it is good estimation

Signed-off-by: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/ath/wil6210/debugfs.c b/drivers/net/wireless/ath/wil6210/debugfs.c
index d90aa28ec7bd17bbea6aa9d8328ce3e6c6ca97c4..9c1102304b938fe1b3b2d4369a5bd8c6adce1842 100644 (file)
--- a/drivers/net/wireless/ath/wil6210/debugfs.c
+++ b/drivers/net/wireless/ath/wil6210/debugfs.c
@@ -69,6 +69,8 @@ static int wil_vring_debugfs_show(struct seq_file *s, void *data)
 
        for (i = 0; i < ARRAY_SIZE(wil->vring_tx); i++) {
                struct vring *vring = &(wil->vring_tx[i]);
+               struct vring_tx_data *txdata = &wil->vring_tx_data[i];
+
                if (vring->va) {
                        int cid = wil->vring2cid_tid[i][0];
                        int tid = wil->vring2cid_tid[i][1];
@@ -78,10 +80,20 @@ static int wil_vring_debugfs_show(struct seq_file *s, void *data)
                                   % vring->size;
                        int avail = vring->size - used - 1;
                        char name[10];
+                       /* performance monitoring */
+                       cycles_t now = get_cycles();
+                       cycles_t idle = txdata->idle;
+                       cycles_t total = now - txdata->begin;
+
+                       txdata->begin = now;
+                       txdata->idle = 0ULL;
+
                        snprintf(name, sizeof(name), "tx_%2d", i);
 
-                       seq_printf(s, "\n%pM CID %d TID %d [%3d|%3d]\n",
-                                  wil->sta[cid].addr, cid, tid, used, avail);
+                       seq_printf(s, "\n%pM CID %d TID %d [%3d|%3d] idle %3d%%\n",
+                                  wil->sta[cid].addr, cid, tid, used, avail,
+                                  (int)((idle*100)/total));
+
                        wil_print_vring(s, wil, name, vring, '_', 'H');
                }
        }

diff --git a/drivers/net/wireless/ath/wil6210/txrx.c b/drivers/net/wireless/ath/wil6210/txrx.c
index c08d041fbe7416132be456295585496365cdc632..0318cd2650ce53eb49c6bf09588b3e8f7e374c92 100644 (file)
--- a/drivers/net/wireless/ath/wil6210/txrx.c
+++ b/drivers/net/wireless/ath/wil6210/txrx.c
@@ -881,6 +881,7 @@ static int wil_tx_vring(struct wil6210_priv *wil, struct vring *vring,
        int nr_frags = skb_shinfo(skb)->nr_frags;
        uint f = 0;
        int vring_index = vring - wil->vring_tx;
+       struct vring_tx_data *txdata = &wil->vring_tx_data[vring_index];
        uint i = swhead;
        dma_addr_t pa;
 
@@ -953,6 +954,9 @@ static int wil_tx_vring(struct wil6210_priv *wil, struct vring *vring,
        wil_hex_dump_txrx("Tx ", DUMP_PREFIX_NONE, 32, 4,
                          (const void *)d, sizeof(*d), false);
 
+       if (wil_vring_is_empty(vring)) /* performance monitoring */
+               txdata->idle += get_cycles() - txdata->last_idle;
+
        /* advance swhead */
        wil_vring_advance_head(vring, nr_frags + 1);
        wil_dbg_txrx(wil, "Tx swhead %d -> %d\n", swhead, vring->swhead);
@@ -1133,8 +1137,10 @@ int wil_tx_complete(struct wil6210_priv *wil, int ringid)
                }
        }
 
-       if (wil_vring_is_empty(vring))
+       if (wil_vring_is_empty(vring)) { /* performance monitoring */
                wil_dbg_txrx(wil, "Ring[%2d] empty\n", ringid);
+               txdata->last_idle = get_cycles();
+       }
 
        if (wil_vring_avail_tx(vring) > wil_vring_wmark_high(vring))
                netif_tx_wake_all_queues(wil_to_ndev(wil));

diff --git a/drivers/net/wireless/ath/wil6210/wil6210.h b/drivers/net/wireless/ath/wil6210/wil6210.h
index 793675ee69a90a3fad008c671ad424f63a117e44..ede4c9f5f5c2cce065ba12b11c80047dfb128717 100644 (file)
--- a/drivers/net/wireless/ath/wil6210/wil6210.h
+++ b/drivers/net/wireless/ath/wil6210/wil6210.h
@@ -20,6 +20,7 @@
 #include <linux/netdevice.h>
 #include <linux/wireless.h>
 #include <net/cfg80211.h>
+#include <linux/timex.h>
 
 #define WIL_NAME "wil6210"
 
@@ -251,7 +252,7 @@ struct vring {
  */
 struct vring_tx_data {
        int enabled;
-
+       cycles_t idle, last_idle, begin;
 };
 
 enum { /* for wil6210_priv.status */