Re: [PATCH 1/5] remove TxStartThresh and RxEarlyThresh
On Mon, 16 Oct 2006 07:26:37 +1000, Benjamin Herrenschmidt said: > Somebody patented FIFO thresholds ? Gack ? The US PTO is fundamentally busticated. http://www.engadget.com/2006/10/14/cisco-patents-the-triple-play/ Cisco got a patent on the concept of delivering voice, internet, and cable TV over one cable. Now admittedly, when they applied for it in 2000, it wasn't a buzzword yet - but I'm pretty sure that there was prior art. Back to the case at hand... In the case of the TxStartThresh and RxEarlyThresh, I don't think it's FIFO thresholds per se that are a problem - the note specifically mentioned cut-through, which is a specific technique of starting to deal with the alread-arrived head end of the packet *before* the tail end has arrived yet. e.g. if you read a packet that has 16 bytes of control info followed by 64 bytes of data, you have finished parsing the first 16 and have set stuff up by the time the 64 bytes starts arriving - even though you only started *one* read of 80 bytes). Of course, even *that* is an old technique - I remember discussion (and possibly implementation) of being able to read the front of an Ethernet packet, and do the routing table lookup fast enough so that you could start transmitting the packet on the outbound interface before it had finished arriving on the inbound. Of course, this was back when Proteon and Bay were start-ups, nobody did IP option fields or router ACLs or stuff like that, and level-3 routers were not much smarter (and perhaps stupider) than today's level-2 switches that filter/route based on MAC address... Maybe the patent is on the fact that you can't do cut-through routing well without enforcing certain relationships on the Rx and Tx FIFO thresholds... pgpvFHZbnBVd4.pgp Description: PGP signature
Re: [PATCH 1/5] remove TxStartThresh and RxEarlyThresh
Ar Llu, 2006-10-16 am 07:26 +1000, ysgrifennodd Benjamin Herrenschmidt: > On Sat, 2006-10-14 at 15:55 -0400, Jesse Huang wrote: > > From: Jesse Huang <[EMAIL PROTECTED]> > > > > Change Logs: > > For patent issue need to remove TxStartThresh and RxEarlyThresh. This > > patent > > is cut-through patent. If use this function, Tx will start to transmit > > after > > few data be move in to Tx FIFO. We are not allow to use those function in > > DFE530/DFE550/DFE580/DL10050/IP100/IP100A. It will decrease a little > > performance. > > Somebody patented FIFO thresholds ? Gack ? 3COM hold several patents on certain kinds of early interrupt/early start for network FIFOs. At least historically they also had a GPL Linux driver that didn't use that feature on their own cards which I'm told was fear of patent "leakage" Alan - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH 1/5] remove TxStartThresh and RxEarlyThresh
On Sat, 2006-10-14 at 15:55 -0400, Jesse Huang wrote: > From: Jesse Huang <[EMAIL PROTECTED]> > > Change Logs: > For patent issue need to remove TxStartThresh and RxEarlyThresh. This patent > is cut-through patent. If use this function, Tx will start to transmit after > few data be move in to Tx FIFO. We are not allow to use those function in > DFE530/DFE550/DFE580/DL10050/IP100/IP100A. It will decrease a little > performance. Somebody patented FIFO thresholds ? Gack ? Ben. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH 1/5] remove TxStartThresh and RxEarlyThresh
From: Jesse Huang <[EMAIL PROTECTED]>
Change Logs:
For patent issue need to remove TxStartThresh and RxEarlyThresh. This patent
is cut-through patent. If use this function, Tx will start to transmit after
few data be move in to Tx FIFO. We are not allow to use those function in
DFE530/DFE550/DFE580/DL10050/IP100/IP100A. It will decrease a little
performance.
Signed-off-by: Jesse Huang <[EMAIL PROTECTED]>
---
drivers/net/sundance.c |8 ++--
1 files changed, 2 insertions(+), 6 deletions(-)
3751714e0fc36905c87a230172d9561c29321833
diff --git a/drivers/net/sundance.c b/drivers/net/sundance.c
index 6b8f4ba..a5dd1c3 100755
--- a/drivers/net/sundance.c
+++ b/drivers/net/sundance.c
@@ -264,8 +264,6 @@ enum alta_offsets {
ASICCtrl = 0x30,
EEData = 0x34,
EECtrl = 0x36,
- TxStartThresh = 0x3c,
- RxEarlyThresh = 0x3e,
FlashAddr = 0x40,
FlashData = 0x44,
TxStatus = 0x46,
@@ -,6 +1109,7 @@ static irqreturn_t intr_handler(int irq,
int tx_cnt;
int tx_status;
int handled = 0;
+ int i;
do {
@@ -1153,17 +1152,14 @@ static irqreturn_t intr_handler(int irq,
np->stats.tx_fifo_errors++;
if (tx_status & 0x02)
np->stats.tx_window_errors++;
+
/*
** This reset has been verified on
** DFE-580TX boards ! [EMAIL PROTECTED]
*/
if (tx_status & 0x10) { /* TxUnderrun */
- unsigned short txthreshold;
-
- txthreshold = ioread16 (ioaddr
+ TxStartThresh);
/* Restart Tx FIFO and
transmitter */
sundance_reset(dev,
(NetworkReset|FIFOReset|TxReset) << 16);
- iowrite16 (txthreshold, ioaddr
+ TxStartThresh);
/* No need to reset the Tx
pointer here */
}
/* Restart the Tx. */
--
1.3.GIT
-
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Re: [PATCH 1/5] remove TxStartThresh and RxEarlyThresh
Sorry, I had typed wrong word. It is because patent issue. Thnaks. - Original Message - From: "Roland Dreier" <[EMAIL PROTECTED]> To: "Andrew Morton" <[EMAIL PROTECTED]> Cc: "Jesse Huang" <[EMAIL PROTECTED]>; ; ; <[EMAIL PROTECTED]> Sent: Monday, October 02, 2006 3:00 PM Subject: Re: [PATCH 1/5] remove TxStartThresh and RxEarlyThresh > > For pattern issue need to remove TxStartThresh and RxEarlyThresh. > Please describe this issue more completely. > > What are the implications of simply removing this feature? Presumably that > code was there for a reason.. Actually I think this patch needs to be handled delicately -- because based on earlier emails from Jesse (http://www.mail-archive.com/netdev@vger.kernel.org/msg22254.html), I am pretty sure that "pattern" is a typo for "patent". So I guess the question is what exactly the patent covers and what the implications of having the current kernel code are. - R. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH 1/5] remove TxStartThresh and RxEarlyThresh
> > For pattern issue need to remove TxStartThresh and RxEarlyThresh. > Please describe this issue more completely. > > What are the implications of simply removing this feature? Presumably that > code was there for a reason.. Actually I think this patch needs to be handled delicately -- because based on earlier emails from Jesse (http://www.mail-archive.com/netdev@vger.kernel.org/msg22254.html), I am pretty sure that "pattern" is a typo for "patent". So I guess the question is what exactly the patent covers and what the implications of having the current kernel code are. - R. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH 1/5] remove TxStartThresh and RxEarlyThresh
On Mon, 02 Oct 2006 14:23:51 -0400 Jesse Huang <[EMAIL PROTECTED]> wrote: > For pattern issue need to remove TxStartThresh and RxEarlyThresh. Please describe this issue more completely. What are the implications of simply removing this feature? Presumably that code was there for a reason.. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH 1/5] remove TxStartThresh and RxEarlyThresh
From: Jesse Huang <[EMAIL PROTECTED]>
Change Logs:
For pattern issue need to remove TxStartThresh and RxEarlyThresh.
Signed-off-by: Jesse Huang <[EMAIL PROTECTED]>
---
drivers/net/sundance.c |8 ++--
1 files changed, 2 insertions(+), 6 deletions(-)
3751714e0fc36905c87a230172d9561c29321833
diff --git a/drivers/net/sundance.c b/drivers/net/sundance.c
index 6b8f4ba..a5dd1c3 100755
--- a/drivers/net/sundance.c
+++ b/drivers/net/sundance.c
@@ -264,8 +264,6 @@ enum alta_offsets {
ASICCtrl = 0x30,
EEData = 0x34,
EECtrl = 0x36,
- TxStartThresh = 0x3c,
- RxEarlyThresh = 0x3e,
FlashAddr = 0x40,
FlashData = 0x44,
TxStatus = 0x46,
@@ -,6 +1109,7 @@ static irqreturn_t intr_handler(int irq,
int tx_cnt;
int tx_status;
int handled = 0;
+ int i;
do {
@@ -1153,17 +1152,14 @@ static irqreturn_t intr_handler(int irq,
np->stats.tx_fifo_errors++;
if (tx_status & 0x02)
np->stats.tx_window_errors++;
+
/*
** This reset has been verified on
** DFE-580TX boards ! [EMAIL PROTECTED]
*/
if (tx_status & 0x10) { /* TxUnderrun */
- unsigned short txthreshold;
-
- txthreshold = ioread16 (ioaddr
+ TxStartThresh);
/* Restart Tx FIFO and
transmitter */
sundance_reset(dev,
(NetworkReset|FIFOReset|TxReset) << 16);
- iowrite16 (txthreshold, ioaddr
+ TxStartThresh);
/* No need to reset the Tx
pointer here */
}
/* Restart the Tx. */
--
1.3.GIT
-
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