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Date: Thu, 18 Aug 2011 10:49:48 +0300
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Subject: Re: [RFC v2 2/5] Bluetooth: Minor optimization for multiple tx connections
From: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
To: Peter Hurley <peter@hurleysoftware.com>
Cc: linux-bluetooth <linux-bluetooth@vger.kernel.org>
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Hi Peter,

On Thu, Aug 18, 2011 at 3:37 AM, Peter Hurley <peter@hurleysoftware.com> wrote:
> When assigning tx quotas for multiple connections, bump fractional
> amounts to the next higher integer. This can reduce the number of
> iterations through the tx scheduler. For example, if 5 avail acl
> buffers are to be used by 3 transmitting connections, the current
> scheduler will produce quotas of 1, 1, 1, 1, 1. This
> optimization will instead produce quotas of 2, 2, 1 (ie., 2 less
> iterations of the tx scheduler).
>
> Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
> ---
> ?net/bluetooth/hci_core.c | ? ?5 ++---
> ?1 files changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
> index 47a31fa..0defa83 100644
> --- a/net/bluetooth/hci_core.c
> +++ b/net/bluetooth/hci_core.c
> @@ -1826,7 +1826,7 @@ static inline struct hci_conn *hci_low_sent(struct hci_dev *hdev, __u8 type, int
> ? ? ? ?}
>
> ? ? ? ?if (conn) {
> - ? ? ? ? ? ? ? int cnt, q;
> + ? ? ? ? ? ? ? int cnt;
>
> ? ? ? ? ? ? ? ?switch (conn->type) {
> ? ? ? ? ? ? ? ?case ACL_LINK:
> @@ -1844,8 +1844,7 @@ static inline struct hci_conn *hci_low_sent(struct hci_dev *hdev, __u8 type, int
> ? ? ? ? ? ? ? ? ? ? ? ?BT_ERR("Unknown link type");
> ? ? ? ? ? ? ? ?}
>
> - ? ? ? ? ? ? ? q = cnt / num;
> - ? ? ? ? ? ? ? *quote = q ? q : 1;
> + ? ? ? ? ? ? ? *quote = (cnt + (num - 1)) / num;
> ? ? ? ?} else
> ? ? ? ? ? ? ? ?*quote = 0;
>
> --
> 1.7.4.1
>

Nice catch, actually after seeing your patch I realize one of my
patches is wrong in assuming an HCI Channel can only be scheduled once
per tx_task, but I guess with your changes we can probably assume so,
right?


-- 
Luiz Augusto von Dentz