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[MEDIUM] detect streaming buffers and tag them as such 

Add the ability to detect streaming buffers, and set a
flag indicating it. It will later serve us in order to
dynamically resize them, and to prioritize file descriptors
during polls.
This commit is contained in:
Willy Tarreau 2008-05-03 23:07:14 +02:00
parent f2e8ee2b46
commit 8a7af60312
2 changed files with 49 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
include/types/buffers.h
View File

@ -53,6 +53,8 @@
#define BF_WRITE_STATUS (BF_PARTIAL_WRITE|BF_COMPLETE_WRITE|BF_WRITE_ERROR|BF_WRITE_NULL)
#define BF_CLEAR_WRITE (~BF_WRITE_STATUS)
#define BF_STREAMER 4096
#define BF_STREAMER_FAST 8192
/* describes a chunk of string */
@ -72,6 +74,8 @@ struct buffer {
unsigned int l; /* data length */
char *r, *w, *lr; /* read ptr, write ptr, last read */
char *rlim; /* read limit, used for header rewriting */
unsigned char xfer_large; /* number of consecutive large xfers */
unsigned char xfer_small; /* number of consecutive small xfers */
unsigned long long total; /* total data read */
char data[BUFSIZE];
};

46
src/stream_sock.c
View File

@ -44,7 +44,7 @@
int stream_sock_read(int fd) {
__label__ out_eternity, out_wakeup, out_shutdown_r, out_error;
struct buffer *b = fdtab[fd].cb[DIR_RD].b;
int ret, max, retval;
int ret, max, retval, cur_read;
int read_poll = MAX_READ_POLL_LOOPS;
#ifdef DEBUG_FULL
@ -61,6 +61,7 @@ int stream_sock_read(int fd) {
if ((fdtab[fd].ev & (FD_POLL_IN|FD_POLL_HUP)) == FD_POLL_HUP)
goto out_shutdown_r;
cur_read = 0;
while (1) {
/*
* 1. compute the maximum block size we can read at once.
@ -110,6 +111,7 @@ int stream_sock_read(int fd) {
if (ret > 0) {
b->r += ret;
b->l += ret;
cur_read += ret;
b->flags |= BF_PARTIAL_READ;
if (b->r == b->data + BUFSIZE) {
@ -122,6 +124,35 @@ int stream_sock_read(int fd) {
/* The buffer is now full, there's no point in going through
* the loop again.
*/
if (!(b->flags & BF_STREAMER_FAST) && (cur_read == b->l)) {
b->xfer_small = 0;
b->xfer_large++;
if (b->xfer_large >= 3) {
/* we call this buffer a fast streamer if it manages
* to be filled in one call 3 consecutive times.
*/
b->flags |= (BF_STREAMER | BF_STREAMER_FAST);
//fputc('+', stderr);
}
}
else if ((b->flags & (BF_STREAMER | BF_STREAMER_FAST)) &&
(cur_read <= BUFSIZE / 2)) {
b->xfer_large = 0;
b->xfer_small++;
if (b->xfer_small >= 2) {
/* if the buffer has been at least half full twice,
* we receive faster than we send, so at least it
* is not a "fast streamer".
*/
b->flags &= ~BF_STREAMER_FAST;
//fputc('-', stderr);
}
}
else {
b->xfer_small = 0;
b->xfer_large = 0;
}
EV_FD_CLR(fd, DIR_RD);
goto out_eternity;
}
@ -133,6 +164,19 @@ int stream_sock_read(int fd) {
* is closed.
*/
if (ret < max) {
if ((b->flags & (BF_STREAMER | BF_STREAMER_FAST)) &&
(cur_read <= BUFSIZE / 2)) {
b->xfer_large = 0;
b->xfer_small++;
if (b->xfer_small >= 3) {
/* we have read less than half of the buffer in
* one pass, and this happened at least 3 times.
* This is definitely not a streamer.
*/
b->flags &= ~(BF_STREAMER | BF_STREAMER_FAST);
//fputc('!', stderr);
}
}
if (fdtab[fd].ev & FD_POLL_HUP)
goto out_shutdown_r;
break;