[Xen-devel] [PATCH] netback: add ethtool stat to track copied skbs

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

# HG changeset patch
# User Ian Campbell <ian.campbell@xxxxxxxxxx>
# Date 1233846695 0
# Node ID 7a24febd95d5abfc03e05de7fa991b11cef14eef
# Parent  4f998fd102e24daa471482730d1a3ff68faa1ad6
netback: add ethtool stat to track copied skbs.

copied skbs should be rare but we have no way of verifying that.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>

diff -r 4f998fd102e2 -r 7a24febd95d5 drivers/xen/netback/common.h
--- a/drivers/xen/netback/common.h      Wed Feb 04 12:26:00 2009 +0000
+++ b/drivers/xen/netback/common.h      Thu Feb 05 15:11:35 2009 +0000
@@ -94,6 +94,9 @@ typedef struct netif_st {
        /* Enforce draining of the transmit queue. */
        struct timer_list tx_queue_timeout;
 
+       /* Statistics */
+       int nr_copied_skbs;
+
        /* Miscellaneous private stuff. */
        struct list_head list;  /* scheduling list */
        atomic_t         refcnt;
diff -r 4f998fd102e2 -r 7a24febd95d5 drivers/xen/netback/interface.c
--- a/drivers/xen/netback/interface.c   Wed Feb 04 12:26:00 2009 +0000
+++ b/drivers/xen/netback/interface.c   Thu Feb 05 15:11:35 2009 +0000
@@ -116,8 +116,51 @@ static int netbk_set_tso(struct net_devi
        return ethtool_op_set_tso(dev, data);
 }
 
+static void netbk_get_drvinfo(struct net_device *dev,
+                             struct ethtool_drvinfo *info)
+{
+       strcpy(info->driver, "netbk");
+}
+
+static const struct netif_stat {
+       char name[ETH_GSTRING_LEN];
+       u16 offset;
+} netbk_stats[] = {
+       { "copied_skbs", offsetof(netif_t, nr_copied_skbs) },
+};
+
+static int netbk_get_stats_count(struct net_device *dev)
+{
+       return ARRAY_SIZE(netbk_stats);
+}
+
+static void netbk_get_ethtool_stats(struct net_device *dev,
+                                  struct ethtool_stats *stats, u64 * data)
+{
+       void *netif = netdev_priv(dev);
+       int i;
+
+       for (i = 0; i < ARRAY_SIZE(netbk_stats); i++)
+               data[i] = *(int *)(netif + netbk_stats[i].offset);
+}
+
+static void netbk_get_strings(struct net_device *dev, u32 stringset, u8 * data)
+{
+       int i;
+
+       switch (stringset) {
+       case ETH_SS_STATS:
+               for (i = 0; i < ARRAY_SIZE(netbk_stats); i++)
+                       memcpy(data + i * ETH_GSTRING_LEN,
+                              netbk_stats[i].name, ETH_GSTRING_LEN);
+               break;
+       }
+}
+
 static struct ethtool_ops network_ethtool_ops =
 {
+       .get_drvinfo = netbk_get_drvinfo,
+
        .get_tx_csum = ethtool_op_get_tx_csum,
        .set_tx_csum = ethtool_op_set_tx_csum,
        .get_sg = ethtool_op_get_sg,
@@ -125,6 +168,10 @@ static struct ethtool_ops network_ethtoo
        .get_tso = ethtool_op_get_tso,
        .set_tso = netbk_set_tso,
        .get_link = ethtool_op_get_link,
+
+       .get_stats_count = netbk_get_stats_count,
+       .get_ethtool_stats = netbk_get_ethtool_stats,
+       .get_strings = netbk_get_strings,
 };
 
 netif_t *netif_alloc(domid_t domid, unsigned int handle)
diff -r 4f998fd102e2 -r 7a24febd95d5 drivers/xen/netback/netback.c
--- a/drivers/xen/netback/netback.c     Wed Feb 04 12:26:00 2009 +0000
+++ b/drivers/xen/netback/netback.c     Thu Feb 05 15:11:35 2009 +0000
@@ -914,7 +914,11 @@ inline static void net_tx_action_dealloc
                        if (time_after(inuse->alloc_time + HZ / 2, jiffies))
                                break;
 
-                       switch (copy_pending_req(inuse - pending_inuse)) {
+                       pending_idx = inuse - pending_inuse;
+
+                       pending_tx_info[pending_idx].netif->nr_copied_skbs++;
+
+                       switch (copy_pending_req(pending_idx)) {
                        case 0:
                                list_move_tail(&inuse->list, &list);
                                continue;

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