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ath10k: simplify rx ring size/fill calculation 

Don't bother with fancy arithmetic and just
hardcode the final values.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
This commit is contained in:
Michal Kazior 2014-11-27 11:12:43 +01:00 committed by Kalle Valo
parent 1cb86d47d4
commit fe2407a889
2 changed files with 12 additions and 89 deletions
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3
drivers/net/wireless/ath/ath10k/htt.h
View File

@ -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;

98
drivers/net/wireless/ath/ath10k/htt_rx.c
View File

@ -25,19 +25,8 @@
#include <linux/log2.h>
/* 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);