From: Michal Kazior Date: Thu, 27 Nov 2014 10:12:43 +0000 (+0100) Subject: ath10k: simplify rx ring size/fill calculation X-Git-Tag: v3.19-rc1~118^2~28^2~42^2 X-Git-Url: http://git.cascardo.info/?p=cascardo%2Flinux.git;a=commitdiff_plain;h=fe2407a889f7b6530b7e231e7c866f5c5d223657 ath10k: simplify rx ring size/fill calculation Don't bother with fancy arithmetic and just hardcode the final values. Signed-off-by: Michal Kazior Signed-off-by: Kalle Valo --- diff --git a/drivers/net/wireless/ath/ath10k/htt.h b/drivers/net/wireless/ath/ath10k/htt.h index 17ca6acbe1c1..1bd5545af903 100644 --- a/drivers/net/wireless/ath/ath10k/htt.h +++ b/drivers/net/wireless/ath/ath10k/htt.h @@ -158,6 +158,9 @@ enum htt_rx_ring_flags { HTT_RX_RING_FLAGS_PHY_DATA_RX = 1 << 15 }; +#define HTT_RX_RING_SIZE_MIN 128 +#define HTT_RX_RING_SIZE_MAX 2048 + struct htt_rx_ring_setup_ring { __le32 fw_idx_shadow_reg_paddr; __le32 rx_ring_base_paddr; diff --git a/drivers/net/wireless/ath/ath10k/htt_rx.c b/drivers/net/wireless/ath/ath10k/htt_rx.c index 85910b2a2373..9c782a42665e 100644 --- a/drivers/net/wireless/ath/ath10k/htt_rx.c +++ b/drivers/net/wireless/ath/ath10k/htt_rx.c @@ -25,19 +25,8 @@ #include -/* slightly larger than one large A-MPDU */ -#define HTT_RX_RING_SIZE_MIN 128 - -/* roughly 20 ms @ 1 Gbps of 1500B MSDUs */ -#define HTT_RX_RING_SIZE_MAX 2048 - -#define HTT_RX_AVG_FRM_BYTES 1000 - -/* ms, very conservative */ -#define HTT_RX_HOST_LATENCY_MAX_MS 20 - -/* ms, conservative */ -#define HTT_RX_HOST_LATENCY_WORST_LIKELY_MS 10 +#define HTT_RX_RING_SIZE 1024 +#define HTT_RX_RING_FILL_LEVEL 1000 /* when under memory pressure rx ring refill may fail and needs a retry */ #define HTT_RX_RING_REFILL_RETRY_MS 50 @@ -45,68 +34,6 @@ static int ath10k_htt_rx_get_csum_state(struct sk_buff *skb); static void ath10k_htt_txrx_compl_task(unsigned long ptr); -static int ath10k_htt_rx_ring_size(struct ath10k_htt *htt) -{ - int size; - - /* - * It is expected that the host CPU will typically be able to - * service the rx indication from one A-MPDU before the rx - * indication from the subsequent A-MPDU happens, roughly 1-2 ms - * later. However, the rx ring should be sized very conservatively, - * to accomodate the worst reasonable delay before the host CPU - * services a rx indication interrupt. - * - * The rx ring need not be kept full of empty buffers. In theory, - * the htt host SW can dynamically track the low-water mark in the - * rx ring, and dynamically adjust the level to which the rx ring - * is filled with empty buffers, to dynamically meet the desired - * low-water mark. - * - * In contrast, it's difficult to resize the rx ring itself, once - * it's in use. Thus, the ring itself should be sized very - * conservatively, while the degree to which the ring is filled - * with empty buffers should be sized moderately conservatively. - */ - - /* 1e6 bps/mbps / 1e3 ms per sec = 1000 */ - size = - htt->max_throughput_mbps + - 1000 / - (8 * HTT_RX_AVG_FRM_BYTES) * HTT_RX_HOST_LATENCY_MAX_MS; - - if (size < HTT_RX_RING_SIZE_MIN) - size = HTT_RX_RING_SIZE_MIN; - - if (size > HTT_RX_RING_SIZE_MAX) - size = HTT_RX_RING_SIZE_MAX; - - size = roundup_pow_of_two(size); - - return size; -} - -static int ath10k_htt_rx_ring_fill_level(struct ath10k_htt *htt) -{ - int size; - - /* 1e6 bps/mbps / 1e3 ms per sec = 1000 */ - size = - htt->max_throughput_mbps * - 1000 / - (8 * HTT_RX_AVG_FRM_BYTES) * HTT_RX_HOST_LATENCY_WORST_LIKELY_MS; - - /* - * Make sure the fill level is at least 1 less than the ring size. - * Leaving 1 element empty allows the SW to easily distinguish - * between a full ring vs. an empty ring. - */ - if (size >= htt->rx_ring.size) - size = htt->rx_ring.size - 1; - - return size; -} - static void ath10k_htt_rx_ring_free(struct ath10k_htt *htt) { struct sk_buff *skb; @@ -462,25 +389,18 @@ int ath10k_htt_rx_alloc(struct ath10k_htt *htt) htt->rx_confused = false; - htt->rx_ring.size = ath10k_htt_rx_ring_size(htt); + /* XXX: The fill level could be changed during runtime in response to + * the host processing latency. Is this really worth it? + */ + htt->rx_ring.size = HTT_RX_RING_SIZE; + htt->rx_ring.size_mask = htt->rx_ring.size - 1; + htt->rx_ring.fill_level = HTT_RX_RING_FILL_LEVEL; + if (!is_power_of_2(htt->rx_ring.size)) { ath10k_warn(ar, "htt rx ring size is not power of 2\n"); return -EINVAL; } - htt->rx_ring.size_mask = htt->rx_ring.size - 1; - - /* - * Set the initial value for the level to which the rx ring - * should be filled, based on the max throughput and the - * worst likely latency for the host to fill the rx ring - * with new buffers. In theory, this fill level can be - * dynamically adjusted from the initial value set here, to - * reflect the actual host latency rather than a - * conservative assumption about the host latency. - */ - htt->rx_ring.fill_level = ath10k_htt_rx_ring_fill_level(htt); - htt->rx_ring.netbufs_ring = kzalloc(htt->rx_ring.size * sizeof(struct sk_buff *), GFP_KERNEL);