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Dummynet has a limit of 100 slots queue size (or 1MB, if you give

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the limit in bytes) hard coded into both the kernel and userland.
Make both these limits a sysctl, so it is easy to change the limit.
If the userland part of ipfw finds that the sysctls don't exist,
it will just fall back to the traditional limits.

(100 packets is quite a small limit these days. If you want to test
TCP at 100Mbps, 100 packets can only accommodate a DBP of 12ms.)

Note these sysctls in the man page and warn against increasing them
without thinking first.

MFC after:      3 weeks
This commit is contained in:
David Malone 2008-02-27 13:52:33 +00:00
parent 64da64c3f7
commit 2b2c3b23d1
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=176626
3 changed files with 41 additions and 7 deletions
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14
sbin/ipfw/ipfw.8
View File

@ -1971,6 +1971,13 @@ or 20s of queue on a 30Kbit/s pipe.
Even worse effects can result if you get packets from an
interface with a much larger MTU, e.g.\& the loopback interface
with its 16KB packets.
The
.Xr sysctl 8
variables
.Em net.inet.ip.dummynet.pipe_byte_limit
and
.Em net.inet.ip.dummynet.pipe_slot_limit
control the maximum lengths that can be specified.
.Pp
.It Cm red | gred Ar w_q Ns / Ns Ar min_th Ns / Ns Ar max_th Ns / Ns Ar max_p
Make use of the RED (Random Early Detection) queue management algorithm.
@ -2190,6 +2197,13 @@ will be expired even when
.It Va net.inet.ip.dummynet.red_max_pkt_size : No 1500
Parameters used in the computations of the drop probability
for the RED algorithm.
.It Va net.inet.ip.dummynet.pipe_byte_limit : No 1048576
.It Va net.inet.ip.dummynet.pipe_slot_limit : No 100
The maximum queue size that can be specified in bytes or packets.
These limits prevent accidental exhaustion of resources such as mbufs.
If you raise these limits,
you should make sure the system is configured so that sufficient resources
are available.
.It Va net.inet.ip.fw.autoinc_step : No 100
Delta between rule numbers when auto-generating them.
The value must be in the range 1..1000.

23
sbin/ipfw/ipfw2.c
View File

@ -4341,11 +4341,25 @@ config_pipe(int ac, char **av)
errx(EX_DATAERR, "weight must be <= 100");
}
if (p.fs.flags_fs & DN_QSIZE_IS_BYTES) {
if (p.fs.qsize > 1024*1024)
errx(EX_DATAERR, "queue size must be < 1MB");
size_t len;
long limit;
len = sizeof(limit);
if (sysctlbyname("net.inet.ip.dummynet.pipe_byte_limit",
&limit, &len, NULL, 0) == -1)
limit = 1024*1024;
if (p.fs.qsize > limit)
errx(EX_DATAERR, "queue size must be < %ldB", limit);
} else {
if (p.fs.qsize > 100)
errx(EX_DATAERR, "2 <= queue size <= 100");
size_t len;
long limit;
len = sizeof(limit);
if (sysctlbyname("net.inet.ip.dummynet.pipe_slot_limit",
&limit, &len, NULL, 0) == -1)
limit = 100;
if (p.fs.qsize > limit)
errx(EX_DATAERR, "2 <= queue size <= %ld", limit);
}
if (p.fs.flags_fs & DN_IS_RED) {
size_t len;
@ -4363,7 +4377,6 @@ config_pipe(int ac, char **av)
len = sizeof(int);
if (sysctlbyname("net.inet.ip.dummynet.red_lookup_depth",
&lookup_depth, &len, NULL, 0) == -1)
errx(1, "sysctlbyname(\"%s\")",
"net.inet.ip.dummynet.red_lookup_depth");
if (lookup_depth == 0)

11
sys/netinet/ip_dummynet.c
View File

@ -98,6 +98,9 @@ static long searches, search_steps ;
static int pipe_expire = 1 ; /* expire queue if empty */
static int dn_max_ratio = 16 ; /* max queues/buckets ratio */
static long pipe_slot_limit = 100; /* Foot shooting limit for pipe queues. */
static long pipe_byte_limit = 1024 * 1024;
static int red_lookup_depth = 256; /* RED - default lookup table depth */
static int red_avg_pkt_size = 512; /* RED - default medium packet size */
static int red_max_pkt_size = 1500; /* RED - default max packet size */
@ -198,6 +201,10 @@ SYSCTL_ULONG(_net_inet_ip_dummynet, OID_AUTO, io_pkt_fast,
SYSCTL_ULONG(_net_inet_ip_dummynet, OID_AUTO, io_pkt_drop,
CTLFLAG_RD, &io_pkt_drop, 0,
"Number of packets dropped by dummynet.");
SYSCTL_LONG(_net_inet_ip_dummynet, OID_AUTO, pipe_slot_limit,
CTLFLAG_RW, &pipe_slot_limit, 0, "Upper limit in slots for pipe queue.");
SYSCTL_LONG(_net_inet_ip_dummynet, OID_AUTO, pipe_byte_limit,
CTLFLAG_RW, &pipe_byte_limit, 0, "Upper limit in bytes for pipe queue.");
#endif
#ifdef DUMMYNET_DEBUG
@ -1692,12 +1699,12 @@ set_fs_parms(struct dn_flow_set *x, struct dn_flow_set *src)
x->plr = src->plr;
x->flow_mask = src->flow_mask;
if (x->flags_fs & DN_QSIZE_IS_BYTES) {
if (x->qsize > 1024 * 1024)
if (x->qsize > pipe_byte_limit)
x->qsize = 1024 * 1024;
} else {
if (x->qsize == 0)
x->qsize = 50;
if (x->qsize > 100)
if (x->qsize > pipe_slot_limit)
x->qsize = 50;
}
/* Configuring RED. */