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Improved read-ahead buffer management

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git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@430 42af7a65-404d-4744-a932-0658087f49c3
This commit is contained in:
patacongo 2007-12-06 23:10:31 +00:00
parent cba8fa9596
commit a932e62067
3 changed files with 78 additions and 24 deletions
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1
ChangeLog
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@ -268,3 +268,4 @@
* Implemented send() timeout logic
* Add a skeleton Ethernet device driver (drivers/net/skeleton.c)
* Added C5471 Ethernet device driver (arch/arm/src/c5471/c5471_ethernet.c)
* Improved utilization of read-ahead buffers

1
Documentation/NuttX.html
View File

@ -964,6 +964,7 @@ Other memory:
* Add TELNETD front end to NSH (examples/nsh)
* Add a skeleton Ethernet device driver (drivers/net/skeleton.c)
* Added C5471 Ethernet device driver (arch/arm/src/c5471/c5471_ethernet.c)
* Improved utilization of read-ahead buffers
</pre></ul>
<table width ="100%">

94
net/uip/uip-tcpcallback.c
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@ -59,6 +59,45 @@
* Private Functions
****************************************************************************/
/****************************************************************************
* Function: uip_readahead
*
* Description:
* Copy as much received data as possible into the readahead buffer
*
* Assumptions:
* This function is called at the interrupt level with interrupts disabled.
*
****************************************************************************/
#if CONFIG_NET_NTCP_READAHEAD_BUFFERS > 0
static int uip_readahead(struct uip_readahead_s *readahead, uint8 *buf, int len)
{
int available = CONFIG_NET_TCP_READAHEAD_BUFSIZE - readahead->rh_nbytes;
int recvlen = 0;
if (len > 0 && available > 0)
{
/* Get the length of the data to buffer. */
if (len > available)
{
recvlen = available;
}
else
{
recvlen = len;
}
/* Copy the new appdata into the read-ahead buffer */
memcpy(&readahead->rh_buffer[readahead->rh_nbytes], buf, recvlen);
readahead->rh_nbytes += recvlen;
}
return recvlen;
}
#endif
/****************************************************************************
* Function: uip_dataevent
*
@ -74,10 +113,6 @@
static inline uint8
uip_dataevent(struct uip_driver_s *dev, struct uip_conn *conn, uint8 flags)
{
#if CONFIG_NET_NTCP_READAHEAD_BUFFERS > 0
struct uip_readahead_s *readahead;
uint16 recvlen;
#endif
uint8 ret = flags;
/* Is there new data? With non-zero length? (Certain connection events
@ -87,39 +122,56 @@ uip_dataevent(struct uip_driver_s *dev, struct uip_conn *conn, uint8 flags)
if ((flags & UIP_NEWDATA) != 0 && dev->d_len > 0)
{
#if CONFIG_NET_NTCP_READAHEAD_BUFFERS > 0
/* Allocate a read-ahead buffer to hold the newly received data */
struct uip_readahead_s *readahead1;
struct uip_readahead_s *readahead2 = NULL;
uint16 recvlen = 0;
uint8 *buf = dev->d_appdata;
int buflen = dev->d_len;
readahead = uip_tcpreadaheadalloc();
if (readahead)
{
/* Get the length of the data to buffer. If the sizes of the
* read-ahead buffers are picked correct, they should always
* hold the full received packet.\
/* First, we need to determine if we have space to buffer the data. This
* needs to be verified before we actually begin buffering the data. We
* will use any remaining space in the last allocated readahead buffer
* plus as much one additional buffer. It is expected that the size of
* readahead buffers are tuned so that one full packet will always fit
* into one readahead buffer (for example if the buffer size is 420, then
* a readahead buffer of 366 will hold a full packet of TCP data).
*/
if (dev->d_len > CONFIG_NET_TCP_READAHEAD_BUFSIZE)
readahead1 = (struct uip_readahead_s*)conn->readahead.tail;
if ((readahead1 &&
(CONFIG_NET_TCP_READAHEAD_BUFSIZE - readahead1->rh_nbytes) > buflen) ||
(readahead2 = uip_tcpreadaheadalloc()) != NULL)
{
recvlen = CONFIG_NET_TCP_READAHEAD_BUFSIZE;
/* We have buffer space. Now try to append add as much data as possible
* to the last readahead buffer attached to this connection.
*/
if (readahead1)
{
recvlen = uip_readahead(readahead1, buf, buflen);
if (recvlen > 0)
{
buf += recvlen;
buflen -= recvlen;
}
else
{
recvlen = dev->d_len;
}
/* Copy the new appdata into the read-ahead buffer */
/* Do we need to buffer into the newly allocated buffer as well? */
memcpy(readahead->rh_buffer, dev->d_appdata, recvlen);
readahead->rh_nbytes = recvlen;
nvdbg("Buffered %d bytes (of %d)\n", recvlen, dev->d_len);
if (readahead2)
{
(void)uip_readahead(readahead2, buf, buflen);
/* Save the readahead buffer in the connection structure where
* it can be found with recv() is called.
*/
sq_addlast(&readahead->rh_node, &conn->readahead);
sq_addlast(&readahead2->rh_node, &conn->readahead);
}
/* Indicate that all of the data in the buffer has been consumed */
nvdbg("Buffered %d bytes\n", dev->d_len);
dev->d_len = 0;
}
else