Date: Sun, 31 Oct 2004 21:35:58 +0100 From: Pawel Malachowski <pawmal-posting@freebsd.lublin.pl> To: freebsd-ipfw@freebsd.org Subject: [PATCH] burstable dummynet pipe Message-ID: <20041031203558.GA49557@shellma.zin.lublin.pl>
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--OXfL5xGRrasGEqWY
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Hello,
Attached (poor) patch (against 5.3-RC1) implements pipes that can be
overloaded (exceed their bw) for a (short) period of time.
It adds yet another parameter for pipe: `burst x', x in (K)Bytes.
Should also work with dynamic (clonable via mask) pipes.
Configuring `x bytes burst' means we are allowing to transmit x bytes
with increased (by default: ~2x) speed. After that, traffic passes
through pipe as usual (bw-limited), however, burst credit is slowly
(by default: ~10x lower than bw) accumulated when pipe is idle (low
traffic, empty ticks). When x bytes of burst credit is accumulated,
one can consume it once again. Etc.
No man page provided.
Sorry for poor coding. Still, seems to work. ;)
Example:
% ipfw add ... // pass my test traffic to pipe 1
% ipfw pipe 1 config bw 256kbit queue 5KB burst 110KB
% ipfw pipe show
00001: 256.000 Kbit/s 0 ms 110 KB 5120 B 1 queues (1 buckets) droptail
mask: 0x00 0x00000000/0x0000 -> 0x00000000/0x0000
% sleep 15
% wget --progress=dot some-file
[...]
HTTP request sent, awaiting response... 200 OK
Length: 10,485,760 [text/plain]
0K .......... .......... .......... .......... .......... 0% 61.80 KB/s
50K .......... .......... .......... .......... .......... 0% 58.14 KB/s
100K .......... .......... .......... .......... .......... 1% 32.05 KB/s
150K .......... .......... .......... .......... .......... 1% 30.49 KB/s
200K .......... .......... .......... .......... .......... 2% 29.59 KB/s
250K .......... .......... .......... .......... .......... 2% 30.30 KB/s
300K .......... .......... .......... .......... .......... 3% 29.59 KB/s
350K .......... .......... .......... .......... .......... 3% 29.41 KB/s
400K .......... .......... ......^C
% sleep 10
% wget --progress=dot some-file
[...]
HTTP request sent, awaiting response... 200 OK
Length: 10,485,760 [text/plain]
0K .......... .......... .......... .......... .......... 0% 26.32 KB/s
50K .......... .......... .......... .......... .......... 0% 33.36 KB/s
100K .......... .......... .......... .......... .......... 1% 28.74 KB/s
150K .......... .......... .......... .......... .......... 1% 31.23 KB/s
200K .......^C
% sleep 15
% wget --progress=dot some-file
[...]
HTTP request sent, awaiting response... 200 OK
Length: 10,485,760 [text/plain]
0K .......... .......... .......... .......... .......... 0% 61.73 KB/s
50K .......... .......... .......... .......... .......... 0% 58.14 KB/s
100K .......... .......... .......... .......... .......... 1% 32.05 KB/s
150K .......... ...^C
--
Paweł Małachowski
--OXfL5xGRrasGEqWY
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--- /sys/netinet/ip_dummynet.c-orig Fri Oct 29 21:34:46 2004
+++ /sys/netinet/ip_dummynet.c Sun Oct 31 20:23:33 2004
@@ -580,14 +580,34 @@
* setting len_scaled = 0 does the job.
*/
q->numbytes += ( curr_time - q->sched_time ) * p->bandwidth;
+#if 0
+ if ( q->burstmode==DN_BURST_FLUSH && (q->currburst < q->numbytes/8/hz) ) {
+ printf("Full burst power. ;)\n");
+ }
+ else if ( q->burstmode==DN_BURST_FLUSH ) { /* currbust >= numbytes/8/hz */
+ printf("Burst getting empty, slow down a bit\n");
+ }
+#endif
while ( (pkt = q->head) != NULL ) {
int len = pkt->m_pkthdr.len;
int len_scaled = p->bandwidth ? len*8*hz : 0 ;
+ if (q->burstmode==DN_BURST_FLUSH)
+ len_scaled /= 2; /* increase burst speed 2x. this will be <2x because we left SET_TICKS untouched but hey, it still works good enough... */
if (len_scaled > q->numbytes )
break ;
q->numbytes -= len_scaled ;
+ if ( q->burstmode==DN_BURST_FLUSH )
+ q->currburst -= len ; /* can go <0, we will fix this later */
move_pkt(pkt, q, p, len);
}
+
+ /* If burst credit is empty, announce that we are accumulatig it now. */
+ if (q->burstmode==DN_BURST_FLUSH && q->currburst<=0) {
+ q->currburst = 0 ;
+ q->burstmode = DN_BURST_ACCUMULATE ; /* will get leftovers if found */
+ //printf("Stop flushing burst (empty), start accumulating!\n");
+ }
+
/*
* If we have more packets queued, schedule next ready event
* (can only occur when bandwidth != 0, otherwise we would have
@@ -603,6 +623,21 @@
* queue on error hoping next time we are luckier.
*/
} else { /* RED needs to know when the queue becomes empty */
+#if 0
+ if ( q->burstmode==DN_BURST_ACCUMULATE ) {
+ /* There are some leftovers, saturation<=bw (can be <).
+ * After some tests I decided not to accumulate them because
+ * burst credit grows even when saturation~=bw and burst
+ * explode from time to time during heavy-downloading
+ * sessions (it looks weird). */
+ q->currburst += ( q->numbytes/(8*hz) );
+ if (q->currburst >= p->burst) {
+ q->currburst = p->burst ;
+ q->burstmode = DN_BURST_FLUSH ;
+ //printf("Accumulate leftovers, we can start flushing burst now.\n");
+ }
+ }
+#endif
q->q_time = curr_time;
q->numbytes = 0;
}
@@ -880,11 +915,14 @@
return NULL ;
}
q->fs = fs ;
+ q->currburst = 0 ; /* we will accumulate burst while waiting */
+ q->burstmode = DN_BURST_ACCUMULATE ;
q->hash_slot = i ;
q->next = fs->rq[i] ;
q->S = q->F + 1; /* hack - mark timestamp as invalid */
fs->rq[i] = q ;
fs->rq_elements++ ;
+
return q ;
}
@@ -1224,9 +1262,35 @@
* Fixed-rate queue: just insert into the ready_heap.
*/
dn_key t = 0 ;
+ dn_key pst = 0 ; /* preserved schedule time */
+ dn_key ct = 0 ; /* computed time, with bw, gives burst credit for idle ticks */
if (pipe->bandwidth)
t = SET_TICKS(m, q, pipe);
+ pst = q->sched_time ;
q->sched_time = curr_time ;
+
+ if (pipe->burst && q->burstmode==DN_BURST_ACCUMULATE) {
+ /* We should use `previous' t, but hey, when passing constant
+ current traffic, t is usually the same or very close.
+ So it is acceptable to use current t value for simplicity. */
+ ct = curr_time - pst - t;
+ /* Make sure, we avoid negative. This happens all the time
+ when bw is full of passing traffic. */
+ if (DN_KEY_LT(curr_time-pst,t)) ct=0;
+
+ /* Pipe was idle for some time, increase burst credit
+ to reflect this.
+ Burst credit can grow slower or faster (but it is always
+ connected with pipe bw), just increase or descrease `a'
+ in this expression: (8*hz*a), a=10 is the default. */
+ q->currburst += ct*pipe->bandwidth/(8*hz*10);
+ if ( q->currburst >= pipe->burst ) {
+ q->currburst = pipe->burst ;
+ q->burstmode = DN_BURST_FLUSH ;
+ }
+ //printf("dummynet_io(): (t=%lld,curr-sched=%lld) added %lld, now currburst=%d(burst=%d)\n", t,ct,(ct) * pipe->bandwidth /(8*hz*10),q->currburst,pipe->burst );
+ }
+
if (t == 0) /* must process it now */
ready_event( q );
else
@@ -1614,6 +1678,7 @@
bcopy(p->if_name, x->if_name, sizeof(p->if_name) );
x->ifp = NULL ; /* reset interface ptr */
x->delay = p->delay ;
+ x->burst = p->bandwidth ? p->burst : 0 ; /* burst is for fixed-bw pipes */
set_fs_parms(&(x->fs), pfs);
--OXfL5xGRrasGEqWY
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Content-Disposition: attachment; filename="burst--ip_dummynet.h.diff"
--- /sys/netinet/ip_dummynet.h-orig Fri Oct 29 21:34:56 2004
+++ /sys/netinet/ip_dummynet.h Sun Oct 31 19:31:36 2004
@@ -208,6 +208,11 @@
u_int len_bytes ;
u_long numbytes ; /* credit for transmission (dynamic queues) */
+ int currburst ; /* current burst buffer credit, in bytes */
+ u_short burstmode ;
+#define DN_BURST_ACCUMULATE 0 /* accumulating burst credit */
+#define DN_BURST_FLUSH 1 /* we can use accumulated burst credit */
+
u_int64_t tot_pkts ; /* statistics counters */
u_int64_t tot_bytes ;
u_int32_t drops ;
@@ -315,6 +320,7 @@
int pipe_nr ; /* number */
int bandwidth; /* really, bytes/tick. */
int delay ; /* really, ticks */
+ int burst ; /* burst buffer credit, in bytes */
struct mbuf *head, *tail ; /* packets in delay line */
--OXfL5xGRrasGEqWY
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Content-Disposition: attachment; filename="burst--ipfw.c.diff"
--- /usr/src/sbin/ipfw/ipfw2.c-orig Fri Oct 29 21:16:23 2004
+++ /usr/src/sbin/ipfw/ipfw2.c Sun Oct 31 20:14:17 2004
@@ -253,6 +253,7 @@
TOK_DROPTAIL,
TOK_PROTO,
TOK_WEIGHT,
+ TOK_BURST,
};
struct _s_x dummynet_params[] = {
@@ -275,6 +276,7 @@
{ "delay", TOK_DELAY },
{ "pipe", TOK_PIPE },
{ "queue", TOK_QUEUE },
+ { "burst", TOK_BURST },
{ "dummynet-params", TOK_NULL },
{ NULL, 0 } /* terminator */
};
@@ -1518,6 +1520,7 @@
for (; nbytes >= sizeof *p; p = (struct dn_pipe *)next) {
double b = p->bandwidth;
char buf[30];
+ char buf2[30];
char prefix[80];
if (p->next != (struct dn_pipe *)DN_IS_PIPE)
@@ -1547,8 +1550,14 @@
else
sprintf(buf, "%7.3f bit/s ", b);
- sprintf(prefix, "%05d: %s %4d ms ",
- p->pipe_nr, buf, p->delay);
+ if (p->burst >= 8192)
+ sprintf(buf2, "%d KB", p->burst / 1024);
+ else
+ sprintf(buf2, "%d B", p->burst);
+
+ sprintf(prefix, "%05d: %s %4d ms %s",
+ p->pipe_nr, buf, p->delay, buf2);
+
print_flowset_parms(&(p->fs), prefix);
if (verbose)
printf(" V %20qd\n", p->V >> MY_M);
@@ -2280,6 +2289,18 @@
p.fs.qsize *= 1024;
} else if (*end == 'B' || !strncmp(end, "by", 2)) {
p.fs.flags_fs |= DN_QSIZE_IS_BYTES;
+ }
+ ac--; av++;
+ break;
+
+ case TOK_BURST:
+ if (do_pipe != 1)
+ errx(EX_DATAERR, "burst only valid for pipes");
+ NEED1("burst needs credit size\n");
+ end = NULL;
+ p.burst = strtoul(av[0], &end, 0);
+ if (*end == 'K' || *end == 'k') {
+ p.burst *= 1024;
}
ac--; av++;
break;
--OXfL5xGRrasGEqWY--
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