This document discusses using Plan 9 concepts like VMRPC and socket outsourcing to improve network performance in virtualized environments like KVM. It proposes implementing a Plan 9-like API that uses hypercalls to delegate socket operations from the guest OS to the host, avoiding virtualized network bottlenecks. Experimental results show this "Socket Outsourcing" approach can increase throughput close to that of using the host's virtio driver directly. The document also outlines how Plan 9 concepts could be ported to other systems like Linux and Windows.

1. Plan 9
/ paravirt.org
/ @go_vm
2010 2 23 @IIJ
Kernel/VM
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2. • / @go_vm
•
•
• KVM
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3. • twitter
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4. ?
Plan 9 ?
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5. 5

6. Plan 9
• Plan9
• 30
• ” ”
• http://circle.paravirt.org/c77
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7. Plan 9 (2)
• ...
• KVM VM
• Plan9
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8. • 09 12 30
•
• 3 50
•
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9. • 2 10 OST
•
9

10. 10

11. 11

12. • VMM
OS OS
• KVM VirtualBox
VMM VMM
• VMM OS OS
Type II VMM
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13. VM CPU
• OS
CPU
•
•
13

14. OS
TEXT main+0(SB),0,$0
MOVL $1,4(SP)
MOVL $.string+0(SB),8(SP)
MOVL $14,12(SP)
MOVL $20,AX
INT $64
MOVL $0,4(SP)
MOVL $8,AX
INT $64
GLOBL .string+0(SB),$16
DATA .string+0(SB)/8,$”Hello, w”
DATA .string+0(SB)/8,$”orld!¥z¥z¥n”
END ,
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15. • CPU
• :
• :
” ”
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16. 16

17. x86
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18. x86
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19. • (VMware)
• (LilyVM)
• (Xen)
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20. •
•
20

21. Intel AMD
• CPU
• Intel → Intel VT (vmx)
• AMD → AMD-V (svm)
• vmx svm
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22. vmx
VMX-root mode VMX-non root mode
VMEntry
( (
) )
VMExit
VMX-non root mode
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23. non-root
•
mode
OS OS
VMM VMM
•
mode
root OS
Type II VMM
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24. root non-root
mode mode
VMM
OS
kernel user
mode mode
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25. •
•
kernel user
mode mode
sysenter
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26. •
26

27. • VMM
non-root
mode
OS
vmcall
• VMM( )
mode
root
VMM
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28. < Plan9>
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29. Plan9
• Plan9 KVM
Plan9
• socket,connect,send,recv
Plan9
29

30. (1)
TEXT vmcall(SB), $0
MOVL b+0(FP),BX
• Plan9
MOVL c+4(FP),CX • BYTE
MOVL d+8(FP),DX vmx vmcall
MOVL $12345, AX
BYTE $0xf
BYTE $0x1
•
BYTE $0xc1
RET
30

31. (2)
• hsocket
int hsocket(int dom,int type,int proto)
{
struct {int d;int t;int p;} arg;
arg.d = dom;
arg.t = type;
• socket
arg.p = proto; FD
return vmcall(0,(int)&arg,sizeof(arg));
}
• KVM
31

32. (3)
int hsend(int fd,void *buf,int len,int flg)
{ • hsend
struct {int fd;void *b;int l;int f;} arg;
arg.fd = fd;
arg.b = buf;
arg.l = len;
arg.f = flg;
• socket
return vmcall(2,(int)&arg,sizeof(arg)); send
}
•
32

33. VMM
• hsend VMM
int hcall_socket(void *opaque,gva_t arg,int len)
{
struct {int dom;int type;int proto;} harg; •
if(sizeof(harg) != len) return -EINVAL;
if(copy_from_guest(opaque,&harg,arg,len))
return -EFAULT;
return socket(harg.dom,
harg.type,
harg.proto);
•
} socket()
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34. 34

35. </ Plan9>
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36. 36

37. Plan9
•
• adhoc
• Plan9
37

38. • Plan9 Plan9
Plan9
38

39. • KVM
• VMRPC
• Socket Outsourcing
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40. VMRPC
• RPC
• → RPC
•
•
•
40

41. VMRPC
OS OS
41
41

42. Socket Outsourcing
• VMRPC Socket Hypercall Interface
• OS Socket API
(BSD Socket )
• Linux,Windows
•
42

43. • OS
TCP/IP
OS
•
NIC VMM
•
OS
‣
43
43

44. •
TCP/IP
OS
• OS
NIC VMM
•
OS
‣
44
44

45. •
TCP/IP OS
OS
• OS
NIC VMM
TCP/IP
OS
‣
45
45

46. Socket Outsourcing
• VMM
• VMRPC
•
46

47. • NIC virtio Socket
Outsourcing iperf
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48. •
• CPU: Intel Core i7 950 3.06GHz
• NIC: Intel 82598EB (10G)
• VMM: KVM88 (VMRPC )
• OS: Linux 2.6.25(SocketOutsourcing
48

49. 10000
7500
[Mbps]
5000
2500
0
e1000(emu) virtio Sos
49

50. 50

51. Plan9
•
• dial API
• /net/tcp
51

52. API
• Plan9 API Sos Socket
• API
• Windows *
*Improving Virtualized Network Performance by Delegating Network Processing
Younggyun Koh,Calton Pu,Yasushi Shinjo,Hideki Eiraku,Go Saito,Daiyuu Nobori
IEEE NCA09
52

53. /net/tcp
• Plan9 /net/tcp
tcp
• SocketOutsourcing
• API
• Plan9
53

54. •
• Plan9
54

55. • KVM
Plan9
• Plan9
55

56. Demo
56

57. • Plan9 Hypercall
• Hypercall
• Plan9
57

58. http://circle.paravirt.org/c77
58