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Use the improved m_uiotombuf() function instead of home grown sosend_copyin()

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to do the userland to kernel copying in sosend_generic() and sosend_dgram().

sosend_copyin() is retained for ZERO_COPY_SOCKETS which are not yet supported
by m_uiotombuf().

Benchmaring shows significant improvements (95% confidence):
 66% less cpu (or 2.9 times better) with new sosend vs. old sosend (non-TSO)
 65% less cpu (or 2.8 times better) with new sosend vs. old sosend (TSO)

(Sender AMD Opteron 852 (2.6GHz) with em(4) PCI-X-133 interface and receiver
DELL Poweredge SC1425 P-IV Xeon 3.2GHz with em(4) LOM connected back to back
at 1000Base-TX full duplex.)

Sponsored by:	TCP/IP Optimization Fundraise 2005
MFC after:	3 month
This commit is contained in:
Andre Oppermann 2006-11-02 17:45:28 +00:00
parent 5e20f43d31
commit 1ae4d97d51
1 changed files with 29 additions and 1 deletions
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30
sys/kern/uipc_socket.c
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@ -813,9 +813,11 @@ struct so_zerocopy_stats so_zerocp_stats = {0,0,0};
#include <vm/vm.h>
#include <vm/vm_page.h>
#include <vm/vm_object.h>
#endif /*ZERO_COPY_SOCKETS*/
/*
* sosend_copyin() is only used if zero copy sockets are enabled. Otherwise
* sosend_dgram() and sosend_generic() use m_uiotombuf().
*
* sosend_copyin() accepts a uio and prepares an mbuf chain holding part or
* all of the data referenced by the uio. If desired, it uses zero-copy.
* *space will be updated to reflect data copied in.
@ -939,6 +941,7 @@ sosend_copyin(struct uio *uio, struct mbuf **retmp, int atomic, long *space,
*retmp = top;
return (error);
}
#endif /*ZERO_COPY_SOCKETS*/
#define SBLOCKWAIT(f) (((f) & MSG_DONTWAIT) ? M_NOWAIT : M_WAITOK)
@ -954,7 +957,9 @@ sosend_dgram(so, addr, uio, top, control, flags, td)
{
long space, resid;
int clen = 0, error, dontroute;
#ifdef ZERO_COPY_SOCKETS
int atomic = sosendallatonce(so) || top;
#endif
KASSERT(so->so_type == SOCK_DGRAM, ("sodgram_send: !SOCK_DGRAM"));
KASSERT(so->so_proto->pr_flags & PR_ATOMIC,
@ -1040,9 +1045,19 @@ sosend_dgram(so, addr, uio, top, control, flags, td)
if (flags & MSG_EOR)
top->m_flags |= M_EOR;
} else {
#ifdef ZERO_COPY_SOCKETS
error = sosend_copyin(uio, &top, atomic, &space, flags);
if (error)
goto out;
#else
top = m_uiotombuf(uio, M_WAITOK, space, max_hdr,
(M_PKTHDR | ((flags & MSG_EOR) ? M_EOR : 0)));
if (top == NULL) {
error = EFAULT; /* only possible error */
goto out;
}
space -= resid - uio->uio_resid;
#endif
resid = uio->uio_resid;
}
KASSERT(resid == 0, ("sosend_dgram: resid != 0"));
@ -1202,12 +1217,25 @@ sosend_generic(so, addr, uio, top, control, flags, td)
if (flags & MSG_EOR)
top->m_flags |= M_EOR;
} else {
#ifdef ZERO_COPY_SOCKETS
error = sosend_copyin(uio, &top, atomic,
&space, flags);
if (error != 0) {
SOCKBUF_LOCK(&so->so_snd);
goto release;
}
#else
top = m_uiotombuf(uio, M_WAITOK, space,
(atomic ? max_hdr : 0),
(atomic ? M_PKTHDR : 0) |
((flags & MSG_EOR) ? M_EOR : 0));
if (top == NULL) {
SOCKBUF_LOCK(&so->so_snd);
error = EFAULT; /* only possible error */
goto release;
}
space -= resid - uio->uio_resid;
#endif
resid = uio->uio_resid;
}
if (dontroute) {