78 lines
3.4 KiB
Diff
78 lines
3.4 KiB
Diff
From 0c7cb8b132f28cd150eb578a73c959de736364a2 Mon Sep 17 00:00:00 2001
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From: Ioana Radulescu <ruxandra.radulescu@nxp.com>
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Date: Mon, 16 Sep 2019 13:15:02 +0300
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Subject: [PATCH] dpaa2-eth: Update FQ taildrop threshold and buffer pool count
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Now that we have congestion group taildrop configured at all
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times, we can afford to increase the frame queue taildrop
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threshold; this will ensure a better response when receiving
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bursts of large-sized frames.
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Also decouple the buffer pool count from the Rx FQ taildrop
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threshold, as above change would increase it too much. Instead,
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keep the old count as a hardcoded value.
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With the new limits, we try to ensure that:
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* we allow enough leeway for large frame bursts (by buffering
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enough of them in queues to avoid heavy dropping in case of
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bursty traffic, but when overall ingress bandwidth is manageable)
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* allow pending frames to be evenly spread between ingress FQs,
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regardless of frame size
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* avoid dropping frames due to the buffer pool being empty; this
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is not a bad behaviour per se, but system overall response is
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more linear and predictable when frames are dropped at frame
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queue/group level.
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Signed-off-by: Ioana Radulescu <ruxandra.radulescu@nxp.com>
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---
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drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h | 23 +++++++++++------------
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1 file changed, 11 insertions(+), 12 deletions(-)
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--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
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+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
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@@ -35,24 +35,24 @@
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/* Convert L3 MTU to L2 MFL */
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#define DPAA2_ETH_L2_MAX_FRM(mtu) ((mtu) + VLAN_ETH_HLEN)
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-/* Set the taildrop threshold (in bytes) to allow the enqueue of several jumbo
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- * frames in the Rx queues (length of the current frame is not
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- * taken into account when making the taildrop decision)
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+/* Set the taildrop threshold (in bytes) to allow the enqueue of a large
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+ * enuough number of jumbo frames in the Rx queues (length of the current
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+ * frame is not taken into account when making the taildrop decision)
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*/
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-#define DPAA2_ETH_FQ_TAILDROP_THRESH (64 * 1024)
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+#define DPAA2_ETH_FQ_TAILDROP_THRESH (1024 * 1024)
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/* Maximum number of Tx confirmation frames to be processed
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* in a single NAPI call
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*/
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#define DPAA2_ETH_TXCONF_PER_NAPI 256
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-/* Buffer quota per queue. Must be large enough such that for minimum sized
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- * frames taildrop kicks in before the bpool gets depleted, so we compute
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- * how many 64B frames fit inside the taildrop threshold and add a margin
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- * to accommodate the buffer refill delay.
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+/* Buffer qouta per channel. We want to keep in check number of ingress frames
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+ * in flight: for small sized frames, congestion group taildrop may kick in
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+ * first; for large sizes, Rx FQ taildrop threshold will ensure only a
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+ * reasonable number of frames will be pending at any given time.
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+ * Ingress frame drop due to buffer pool depletion should be a corner case only
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*/
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-#define DPAA2_ETH_MAX_FRAMES_PER_QUEUE (DPAA2_ETH_FQ_TAILDROP_THRESH / 64)
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-#define DPAA2_ETH_NUM_BUFS (DPAA2_ETH_MAX_FRAMES_PER_QUEUE + 256)
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+#define DPAA2_ETH_NUM_BUFS 1280
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#define DPAA2_ETH_REFILL_THRESH \
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(DPAA2_ETH_NUM_BUFS - DPAA2_ETH_BUFS_PER_CMD)
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@@ -62,8 +62,7 @@
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* taildrop kicks in
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*/
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#define DPAA2_ETH_CG_TAILDROP_THRESH(priv) \
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- (DPAA2_ETH_MAX_FRAMES_PER_QUEUE * dpaa2_eth_queue_count(priv) / \
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- dpaa2_eth_tc_count(priv))
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+ (1024 * dpaa2_eth_queue_count(priv) / dpaa2_eth_tc_count(priv))
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/* Maximum number of buffers that can be acquired/released through a single
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* QBMan command
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