* [PATCH 3/3] Minor improvement for smsc95xx netusb driver performance.
@ 2015-11-25 19:15 Ameen
2015-11-25 21:26 ` Sergei Shtylyov
0 siblings, 1 reply; 3+ messages in thread
From: Ameen @ 2015-11-25 19:15 UTC (permalink / raw)
To: teve.glendinning; +Cc: linux-kernel, linux-usb, Ameen
Reduce number of memcpy's by 1-2 improve transmit performance by 2-4%.
or reduce cpu usage on a comparable value.
Signed-off-by: Ameen Ali <AmeenAli023@gmail.com>
---
drivers/net/usb/smsc95xx.c | 30 ++++++++++++++++--------------
1 file changed, 16 insertions(+), 14 deletions(-)
diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c
index 66b3ab9..022d2f63 100644
--- a/drivers/net/usb/smsc95xx.c
+++ b/drivers/net/usb/smsc95xx.c
@@ -1830,7 +1830,9 @@ static struct sk_buff *smsc95xx_tx_fixup(struct usbnet *dev,
{
bool csum = skb->ip_summed == CHECKSUM_PARTIAL;
int overhead = csum ? SMSC95XX_TX_OVERHEAD_CSUM : SMSC95XX_TX_OVERHEAD;
- u32 tx_cmd_a, tx_cmd_b;
+ struct tx_commands_t {
+ u32 cmd_a, cmd_b, csum_preamble;
+ }tx_cmds;
/* We do not advertise SG, so skbs should be already linearized */
BUG_ON(skb_shinfo(skb)->nr_frags);
@@ -1855,26 +1857,26 @@ static struct sk_buff *smsc95xx_tx_fixup(struct usbnet *dev,
+ skb->csum_offset)) = csum_fold(calc);
csum = false;
+ overhead = SMSC95XX_TX_OVERHEAD;
} else {
- u32 csum_preamble = smsc95xx_calc_csum_preamble(skb);
+ tx_cmds.csum_preamble = smsc95xx_calc_csum_preamble(skb);
skb_push(skb, 4);
- cpu_to_le32s(&csum_preamble);
- memcpy(skb->data, &csum_preamble, 4);
+ cpu_to_le32s(&tx_cmds.csum_preamble);
}
}
- skb_push(skb, 4);
- tx_cmd_b = (u32)(skb->len - 4);
+ tx_cmds.cmd_a = (u32)(skb->len) | TX_CMD_A_FIRST_SEG_ |
+ TX_CMD_A_LAST_SEG_;
+
+ cpu_to_le32s(&tx_cmds.cmd_a);
+
+ tx_cmds.cmd_b = (u32)(skb->len);
if (csum)
- tx_cmd_b |= TX_CMD_B_CSUM_ENABLE;
- cpu_to_le32s(&tx_cmd_b);
- memcpy(skb->data, &tx_cmd_b, 4);
+ tx_cmds.cmd_b |= TX_CMD_B_CSUM_ENABLE;
+ cpu_to_le32s(&tx_cmds.cmd_b);
- skb_push(skb, 4);
- tx_cmd_a = (u32)(skb->len - 8) | TX_CMD_A_FIRST_SEG_ |
- TX_CMD_A_LAST_SEG_;
- cpu_to_le32s(&tx_cmd_a);
- memcpy(skb->data, &tx_cmd_a, 4);
+ skb_push(skb, 8);
+ memcpy(skb->data, &tx_cmds, overhead);
return skb;
}
--
2.5.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH 3/3] Minor improvement for smsc95xx netusb driver performance.
@ 2015-11-25 19:19 Ameen
0 siblings, 0 replies; 3+ messages in thread
From: Ameen @ 2015-11-25 19:19 UTC (permalink / raw)
To: steve.glendinning; +Cc: linux-kernel, linux-usb, Ameen
Reduce number of memcpy's by 1-2 improve transmit performance by 2-4%.
or reduce cpu usage on a comparable value.
Signed-off-by: Ameen Ali <AmeenAli023@gmail.com>
---
drivers/net/usb/smsc95xx.c | 30 ++++++++++++++++--------------
1 file changed, 16 insertions(+), 14 deletions(-)
diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c
index 66b3ab9..022d2f63 100644
--- a/drivers/net/usb/smsc95xx.c
+++ b/drivers/net/usb/smsc95xx.c
@@ -1830,7 +1830,9 @@ static struct sk_buff *smsc95xx_tx_fixup(struct usbnet *dev,
{
bool csum = skb->ip_summed == CHECKSUM_PARTIAL;
int overhead = csum ? SMSC95XX_TX_OVERHEAD_CSUM : SMSC95XX_TX_OVERHEAD;
- u32 tx_cmd_a, tx_cmd_b;
+ struct tx_commands_t {
+ u32 cmd_a, cmd_b, csum_preamble;
+ }tx_cmds;
/* We do not advertise SG, so skbs should be already linearized */
BUG_ON(skb_shinfo(skb)->nr_frags);
@@ -1855,26 +1857,26 @@ static struct sk_buff *smsc95xx_tx_fixup(struct usbnet *dev,
+ skb->csum_offset)) = csum_fold(calc);
csum = false;
+ overhead = SMSC95XX_TX_OVERHEAD;
} else {
- u32 csum_preamble = smsc95xx_calc_csum_preamble(skb);
+ tx_cmds.csum_preamble = smsc95xx_calc_csum_preamble(skb);
skb_push(skb, 4);
- cpu_to_le32s(&csum_preamble);
- memcpy(skb->data, &csum_preamble, 4);
+ cpu_to_le32s(&tx_cmds.csum_preamble);
}
}
- skb_push(skb, 4);
- tx_cmd_b = (u32)(skb->len - 4);
+ tx_cmds.cmd_a = (u32)(skb->len) | TX_CMD_A_FIRST_SEG_ |
+ TX_CMD_A_LAST_SEG_;
+
+ cpu_to_le32s(&tx_cmds.cmd_a);
+
+ tx_cmds.cmd_b = (u32)(skb->len);
if (csum)
- tx_cmd_b |= TX_CMD_B_CSUM_ENABLE;
- cpu_to_le32s(&tx_cmd_b);
- memcpy(skb->data, &tx_cmd_b, 4);
+ tx_cmds.cmd_b |= TX_CMD_B_CSUM_ENABLE;
+ cpu_to_le32s(&tx_cmds.cmd_b);
- skb_push(skb, 4);
- tx_cmd_a = (u32)(skb->len - 8) | TX_CMD_A_FIRST_SEG_ |
- TX_CMD_A_LAST_SEG_;
- cpu_to_le32s(&tx_cmd_a);
- memcpy(skb->data, &tx_cmd_a, 4);
+ skb_push(skb, 8);
+ memcpy(skb->data, &tx_cmds, overhead);
return skb;
}
--
2.5.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH 3/3] Minor improvement for smsc95xx netusb driver performance.
2015-11-25 19:15 [PATCH 3/3] Minor improvement for smsc95xx netusb driver performance Ameen
@ 2015-11-25 21:26 ` Sergei Shtylyov
0 siblings, 0 replies; 3+ messages in thread
From: Sergei Shtylyov @ 2015-11-25 21:26 UTC (permalink / raw)
To: Ameen, teve.glendinning; +Cc: linux-kernel, linux-usb
Hello.
On 11/25/2015 10:15 PM, Ameen wrote:
> Reduce number of memcpy's by 1-2 improve transmit performance by 2-4%.
> or reduce cpu usage on a comparable value.
CPU.
> Signed-off-by: Ameen Ali <AmeenAli023@gmail.com>
> ---
> drivers/net/usb/smsc95xx.c | 30 ++++++++++++++++--------------
> 1 file changed, 16 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c
> index 66b3ab9..022d2f63 100644
> --- a/drivers/net/usb/smsc95xx.c
> +++ b/drivers/net/usb/smsc95xx.c
> @@ -1830,7 +1830,9 @@ static struct sk_buff *smsc95xx_tx_fixup(struct usbnet *dev,
> {
> bool csum = skb->ip_summed == CHECKSUM_PARTIAL;
> int overhead = csum ? SMSC95XX_TX_OVERHEAD_CSUM : SMSC95XX_TX_OVERHEAD;
> - u32 tx_cmd_a, tx_cmd_b;
> + struct tx_commands_t {
> + u32 cmd_a, cmd_b, csum_preamble;
> + }tx_cmds;
Need space after }.
>
> /* We do not advertise SG, so skbs should be already linearized */
> BUG_ON(skb_shinfo(skb)->nr_frags);
> @@ -1855,26 +1857,26 @@ static struct sk_buff *smsc95xx_tx_fixup(struct usbnet *dev,
[...]
>
> - skb_push(skb, 4);
> - tx_cmd_b = (u32)(skb->len - 4);
> + tx_cmds.cmd_a = (u32)(skb->len) | TX_CMD_A_FIRST_SEG_ |
Parens around 'skb->len' not needed.
[...]
MBR, Sergei
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