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more mbuf counter
Hi,
I want to figure out when expensive operations on mbufs happen. If
the memory layout is not optimal, m_defrag(), m_prepend(), m_pullup(),
and m_pulldown() will allocate mbufs or copy memory. I want to
count these operations to find possible optimizations.
netstat -m now shows:
667 mbufs in use:
432 mbufs allocated to data
225 mbufs allocated to packet headers
10 mbufs allocated to socket names and addresses
207/296 mbuf 2048 byte clusters in use (current/peak)
0/60 mbuf 2112 byte clusters in use (current/peak)
0/24 mbuf 4096 byte clusters in use (current/peak)
0/16 mbuf 8192 byte clusters in use (current/peak)
0/14 mbuf 9216 byte clusters in use (current/peak)
0/10 mbuf 12288 byte clusters in use (current/peak)
0/16 mbuf 16384 byte clusters in use (current/peak)
0/248 mbuf 65536 byte clusters in use (current/peak)
10400/17600/8000000 Kbytes allocated to network (current/peak/max)
0 requests for memory denied
0 requests for memory delayed
0 calls to protocol drain routines
125 defrag mbuf allocation
141 prepend mbuf allocation
0 pullup mbuf allocation
0 pullup memory copy
0 pulldown mbuf allocation
0 pulldown memory copy
ok?
bluhm
Index: sys/kern/kern_sysctl.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/kern/kern_sysctl.c,v
diff -u -p -r1.445 kern_sysctl.c
--- sys/kern/kern_sysctl.c 26 Aug 2024 08:24:25 -0000 1.445
+++ sys/kern/kern_sysctl.c 28 Aug 2024 12:09:45 -0000
@@ -530,7 +530,6 @@ kern_sysctl(int *name, u_int namelen, vo
return (sysctl_rdstruct(oldp, oldlenp, newp, &bt, sizeof bt));
}
case KERN_MBSTAT: {
- extern struct cpumem *mbstat;
uint64_t counters[MBSTAT_COUNT];
struct mbstat mbs;
unsigned int i;
@@ -543,6 +542,12 @@ kern_sysctl(int *name, u_int namelen, vo
mbs.m_drops = counters[MBSTAT_DROPS];
mbs.m_wait = counters[MBSTAT_WAIT];
mbs.m_drain = counters[MBSTAT_DRAIN];
+ mbs.m_defrag_alloc = counters[MBSTAT_DEFRAG_ALLOC];
+ mbs.m_prepend_alloc = counters[MBSTAT_PREPEND_ALLOC];
+ mbs.m_pullup_alloc = counters[MBSTAT_PULLUP_ALLOC];
+ mbs.m_pullup_copy = counters[MBSTAT_PULLUP_COPY];
+ mbs.m_pulldown_alloc = counters[MBSTAT_PULLDOWN_ALLOC];
+ mbs.m_pulldown_copy = counters[MBSTAT_PULLDOWN_COPY];
return (sysctl_rdstruct(oldp, oldlenp, newp,
&mbs, sizeof(mbs)));
Index: sys/kern/uipc_mbuf.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/kern/uipc_mbuf.c,v
diff -u -p -r1.290 uipc_mbuf.c
--- sys/kern/uipc_mbuf.c 5 Mar 2024 18:52:41 -0000 1.290
+++ sys/kern/uipc_mbuf.c 28 Aug 2024 11:42:15 -0000
@@ -234,8 +234,6 @@ struct mbuf *
m_get(int nowait, int type)
{
struct mbuf *m;
- struct counters_ref cr;
- uint64_t *counters;
int s;
KASSERT(type >= 0 && type < MT_NTYPES);
@@ -245,9 +243,7 @@ m_get(int nowait, int type)
return (NULL);
s = splnet();
- counters = counters_enter(&cr, mbstat);
- counters[type]++;
- counters_leave(&cr, mbstat);
+ counters_inc(mbstat, type);
splx(s);
m->m_type = type;
@@ -267,8 +263,6 @@ struct mbuf *
m_gethdr(int nowait, int type)
{
struct mbuf *m;
- struct counters_ref cr;
- uint64_t *counters;
int s;
KASSERT(type >= 0 && type < MT_NTYPES);
@@ -278,9 +272,7 @@ m_gethdr(int nowait, int type)
return (NULL);
s = splnet();
- counters = counters_enter(&cr, mbstat);
- counters[type]++;
- counters_leave(&cr, mbstat);
+ counters_inc(mbstat, type);
splx(s);
m->m_type = type;
@@ -417,17 +409,13 @@ struct mbuf *
m_free(struct mbuf *m)
{
struct mbuf *n;
- struct counters_ref cr;
- uint64_t *counters;
int s;
if (m == NULL)
return (NULL);
s = splnet();
- counters = counters_enter(&cr, mbstat);
- counters[m->m_type]--;
- counters_leave(&cr, mbstat);
+ counters_dec(mbstat, m->m_type);
splx(s);
n = m->m_next;
@@ -557,6 +545,7 @@ m_defrag(struct mbuf *m, int how)
KASSERT(m->m_flags & M_PKTHDR);
+ counters_inc(mbstat, MBSTAT_DEFRAG_ALLOC);
if ((m0 = m_gethdr(how, m->m_type)) == NULL)
return (ENOBUFS);
if (m->m_pkthdr.len > MHLEN) {
@@ -616,6 +605,7 @@ m_prepend(struct mbuf *m, int len, int h
m->m_data -= len;
m->m_len += len;
} else {
+ counters_inc(mbstat, MBSTAT_PREPEND_ALLOC);
MGET(mn, how, m->m_type);
if (mn == NULL) {
m_freem(m);
@@ -956,8 +946,8 @@ m_pullup(struct mbuf *m0, int len)
memmove(head, mtod(m0, caddr_t), m0->m_len);
m0->m_data = head;
}
-
len -= m0->m_len;
+ counters_inc(mbstat, MBSTAT_PULLUP_COPY);
} else {
/* the first mbuf is too small or read-only, make a new one */
space = adj + len;
@@ -968,6 +958,7 @@ m_pullup(struct mbuf *m0, int len)
m0->m_next = m;
m = m0;
+ counters_inc(mbstat, MBSTAT_PULLUP_ALLOC);
MGET(m0, M_DONTWAIT, m->m_type);
if (m0 == NULL)
goto bad;
Index: sys/kern/uipc_mbuf2.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/kern/uipc_mbuf2.c,v
diff -u -p -r1.45 uipc_mbuf2.c
--- sys/kern/uipc_mbuf2.c 12 Dec 2020 11:48:54 -0000 1.45
+++ sys/kern/uipc_mbuf2.c 28 Aug 2024 12:12:19 -0000
@@ -66,6 +66,7 @@
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/pool.h>
+#include <sys/percpu.h>
#include <sys/mbuf.h>
extern struct pool mtagpool;
@@ -117,6 +118,7 @@ m_pulldown(struct mbuf *m, int off, int
if (len <= n->m_len - off) {
struct mbuf *mlast;
+ counters_inc(mbstat, MBSTAT_PULLDOWN_ALLOC);
o = m_dup1(n, off, n->m_len - off, M_DONTWAIT);
if (o == NULL) {
m_freem(m);
@@ -158,6 +160,7 @@ m_pulldown(struct mbuf *m, int off, int
*/
if ((off == 0 || offp) && m_trailingspace(n) >= tlen &&
!sharedcluster) {
+ counters_inc(mbstat, MBSTAT_PULLDOWN_COPY);
m_copydata(n->m_next, 0, tlen, mtod(n, caddr_t) + n->m_len);
n->m_len += tlen;
m_adj(n->m_next, tlen);
@@ -167,6 +170,7 @@ m_pulldown(struct mbuf *m, int off, int
!sharedcluster && n->m_next->m_len >= tlen) {
n->m_next->m_data -= hlen;
n->m_next->m_len += hlen;
+ counters_inc(mbstat, MBSTAT_PULLDOWN_COPY);
memmove(mtod(n->m_next, caddr_t), mtod(n, caddr_t) + off, hlen);
n->m_len -= hlen;
n = n->m_next;
@@ -182,6 +186,7 @@ m_pulldown(struct mbuf *m, int off, int
m_freem(m);
return (NULL);
}
+ counters_inc(mbstat, MBSTAT_PULLDOWN_ALLOC);
MGET(o, M_DONTWAIT, m->m_type);
if (o && len > MLEN) {
MCLGETL(o, M_DONTWAIT, len);
Index: sys/sys/mbuf.h
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/sys/mbuf.h,v
diff -u -p -r1.263 mbuf.h
--- sys/sys/mbuf.h 14 Apr 2024 20:46:27 -0000 1.263
+++ sys/sys/mbuf.h 28 Aug 2024 12:08:48 -0000
@@ -363,11 +363,17 @@ u_int mextfree_register(void (*)(caddr_t
/* length to m_copy to copy all */
#define M_COPYALL 1000000000
-#define MBSTAT_TYPES MT_NTYPES
-#define MBSTAT_DROPS (MBSTAT_TYPES + 0)
-#define MBSTAT_WAIT (MBSTAT_TYPES + 1)
-#define MBSTAT_DRAIN (MBSTAT_TYPES + 2)
-#define MBSTAT_COUNT (MBSTAT_TYPES + 3)
+#define MBSTAT_TYPES MT_NTYPES
+#define MBSTAT_DROPS (MBSTAT_TYPES + 0)
+#define MBSTAT_WAIT (MBSTAT_TYPES + 1)
+#define MBSTAT_DRAIN (MBSTAT_TYPES + 2)
+#define MBSTAT_DEFRAG_ALLOC (MBSTAT_TYPES + 3)
+#define MBSTAT_PREPEND_ALLOC (MBSTAT_TYPES + 4)
+#define MBSTAT_PULLUP_ALLOC (MBSTAT_TYPES + 5)
+#define MBSTAT_PULLUP_COPY (MBSTAT_TYPES + 6)
+#define MBSTAT_PULLDOWN_ALLOC (MBSTAT_TYPES + 7)
+#define MBSTAT_PULLDOWN_COPY (MBSTAT_TYPES + 8)
+#define MBSTAT_COUNT (MBSTAT_TYPES + 10)
/*
* Mbuf statistics.
@@ -378,8 +384,14 @@ struct mbstat {
u_long m_drops; /* times failed to find space */
u_long m_wait; /* times waited for space */
u_long m_drain; /* times drained protocols for space */
- u_long m_mtypes[MBSTAT_COUNT];
+ u_long m_mtypes[MBSTAT_TYPES];
/* type specific mbuf allocations */
+ u_long m_defrag_alloc;
+ u_long m_prepend_alloc;
+ u_long m_pullup_alloc;
+ u_long m_pullup_copy;
+ u_long m_pulldown_alloc;
+ u_long m_pulldown_copy;
};
#include <sys/mutex.h>
@@ -404,6 +416,7 @@ extern long nmbclust; /* limit on the
extern int max_linkhdr; /* largest link-level header */
extern int max_protohdr; /* largest protocol header */
extern int max_hdr; /* largest link+protocol header */
+extern struct cpumem *mbstat; /* mbuf statistics counter */
void mbinit(void);
void mbcpuinit(void);
Index: usr.bin/netstat/mbuf.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/usr.bin/netstat/mbuf.c,v
diff -u -p -r1.45 mbuf.c
--- usr.bin/netstat/mbuf.c 16 Jul 2023 03:01:31 -0000 1.45
+++ usr.bin/netstat/mbuf.c 28 Aug 2024 12:21:15 -0000
@@ -79,7 +79,7 @@ static struct mbtypes {
};
int nmbtypes = sizeof(mbstat.m_mtypes) / sizeof(u_long);
-bool seen[MBSTAT_COUNT]; /* "have we seen this type yet?" */
+bool seen[MBSTAT_TYPES]; /* "have we seen this type yet?" */
/*
* Print mbuf statistics.
@@ -93,7 +93,7 @@ mbpr(void)
struct mbtypes *mp;
size_t size;
- if (nmbtypes != MBSTAT_COUNT) {
+ if (nmbtypes != MBSTAT_TYPES) {
fprintf(stderr,
"%s: unexpected change to mbstat; check source\n",
__progname);
@@ -205,4 +205,10 @@ mbpr(void)
printf("%lu requests for memory denied\n", mbstat.m_drops);
printf("%lu requests for memory delayed\n", mbstat.m_wait);
printf("%lu calls to protocol drain routines\n", mbstat.m_drain);
+ printf("%lu defrag mbuf allocation\n", mbstat.m_defrag_alloc);
+ printf("%lu prepend mbuf allocation\n", mbstat.m_prepend_alloc);
+ printf("%lu pullup mbuf allocation\n", mbstat.m_pullup_alloc);
+ printf("%lu pullup memory copy\n", mbstat.m_pullup_copy);
+ printf("%lu pulldown mbuf allocation\n", mbstat.m_pulldown_alloc);
+ printf("%lu pulldown memory copy\n", mbstat.m_pulldown_copy);
}
more mbuf counter