203 lines
8.4 KiB
Plaintext
203 lines
8.4 KiB
Plaintext
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note: for items where i give three default values, the first is for
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small machines (<12.5 MB), the second is medium machines (12.5 to 20
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MB) and the third is for large machines (> 20 MB).
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**** AFD is the driver which handles winsock. the following values
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may be set under Services\Afd\Parameters:
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LargeBufferSize, REG_DWORD, default = 3876
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the size in bytes of large buffers used by AFD. smaller values use
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less memory, larger values can improve performance.
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LargBufferListDepth, REG_DWORD, default = 0/2/10
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the maximum count of large buffers that AFD keeps in reserve. larger
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numbers give better performance at the cost of physical memory.
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MediumBufferSize, REG_DWORD, default = 1504
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size of medium buffers.
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MediumBufferListDepth, REG_DWORD, default = 4/8/16
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max count of medium buffers in reserve.
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SmallBufferSize, REG_DWORD, default = 128
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SmallBufferListDepth, REG_DWORD, default = 8/16/16
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FastSendDatagramThreshold, REG_DWORD, default = 1024
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datagrams smaller than this get bufferred on send, larger ones are
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pended. the default value was found by testing to be the best
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overall value for performance. it is unlikely that anyone would want
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to change this.
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StandardAddressLength, REG_DWORD, default = 24
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the length of TDI addresses typically used for the machine. if the
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customer has a transport protocol like TP4 which uses very long
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addresses, then increasing this value will result in a slight
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performance improvement.
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DefaultReceiveWindow, REG_DWORD, default = 8192
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the number of receive bytes AFD will buffer on a connection before
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imposing flow control. for some applications, a larger value here
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will give slightly better performance at the expense of increases
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resource utilization. note that applications can modify this value
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on a per-socket basis with the SO_RCVBUF socket option.
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DefaultSendWindow, REG_DWORD, default = 8192
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as with DefaultReceiveWindow, but for the send side of connections.
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BufferMultiplier, REG_DWORD, default = 512
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DefaultReceiveWindow and DefaultSendWindow get divided by this value
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to determine how many massages can be sent/received before flow
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control is imposed.
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PriorityBoost, REG_DWORD, default = 2
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the priority boost AFD gives to a thread when it completes I/O for
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that thread. if a multithreaded application experiences starvation
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of some threads, reducing this value may remedy the problem.
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IrpStackSize, REG_DWORD, default = 4
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the count of IRP stack locations used by default for AFD. users
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shouldn't need to change this.
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TransmitIoLength, REG_DWORD, default = PAGE_SIZE,PAGE_SIZE*2,65536
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the default size for I/O (reads and sends) performed by TransmitFile().
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Note that for the NT workstation product, the default I/O size is
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exactly one page.
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IgnorePushBitOnReceives, REG_DWORD, default = 0
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If this value is zero (the default) and the TCP push bit is set on a
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receive indication, then a larger then necessary buffer is passed down
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to the TCP stack. This often gives a performance boost on receives.
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If this value is non-zero, then the TCP push bit is ignored (this was
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the behaviour of NT 3.1).
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MaxActiveTransmitFileCount, REG_DWORD, default = 0
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This value controls the maximum number of simultaneous TransmitFile
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operations allowed. This registry value is only honored in the NT
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Server product; NT Workstations always use a hardcoded (not configurable)
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value.
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MaxFastTransmit, REG_DWORD, default = 65536
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This is the threshold count, in bytes, for the TransmitFile fast path to
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fail. If the caller requests a send larger than this, it will never
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go through the TransmitFile fast path.
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MaxFastCopyTransmit, REG_DWORD, default = 3876
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If a TransmitFile caller requests a send smaller than this size, the
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operation is performed by doing a data copy from the file data to a system
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buffer. This is slightly faster than direct I/O for small files, but for
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larger files the copy overhead overwhelms the inherent efficiency of the
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copy operation.
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TransmitWorker, REG_DWORD, default=0x10
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Specifies how afd should schedule work items to process long
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(more than one send) transmit file request. By default (0x10)
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afd uses system worker threads, with 0x20 it will use kernel
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APC's in the context of the thread that initiated the request.
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0x20 reduces number of context switches and potentially improves
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performance, however, if thread that originated TransmitFile
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request is used for heavy computation, it may not be interrupted
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by the OS scheduler for significant period of time (up to a full
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quantum) and APC will not get processed thus starwing request
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processing
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DisableRawSecurity, REG_DWORD default = 0;
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Non-zero value tells afd to not require admin privilege
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to open a raw socket.
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DisableAddressSharing, REG_DWORD, default = 0
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Disallows sharing of ports between processes even if application
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specifies SO_REUSEADDR in an attempt to hajack some other
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application's port. Setting this flag will tighten security
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although at the expense of additional checking for each created
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socket as well as possibility of breaking some application which
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require socket sharing accross processes
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EnableDynamicBacklog, REG_DWORD, default = 0
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Enables dynamic backlog algorithm on listening endpoints in
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an attempt to thwart off syn attacks: //
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If the free connection count has dropped below the configured
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minimum, the number of "quasi-free" connections is less than
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the configured maximum, and we haven't already queued enough
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requests to take us past the maximum, then add new free
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connections to the endpoint. "Quasi-free" is defined as the
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sum of the free connection count and the count of pending TDI
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accepts.
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MinimumDynamicBacklog, REG_DWORD, default = 0
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MaximumDynamicBacklog, REG_DWORD, default = 0
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DynamicBacklogGrowthDelta, REG_DWORD, default = 0
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Parameters in the algorithm described above.
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*********** THE KEYS BELOW SHOULD NO LONGER BE RELEVANT *********
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(however, some code may be still using them)
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*********** SEE WINSOCK2 SPECIFICATION **************************
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**** the following keys are used by the RNR (service resolution and
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registration) apis in winsock. these are all just "pointers" to
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other stuff in the registry. users should never need to change
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these.
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under CurrentControlSet\Control\ServiceProvider\Order, values:
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ExcludedProviders: a REG_MULTI_SZ that contains decimal values
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corresponding to name space providers that should be excluded.
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default is an empty set. some name space provider decimal values
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include:
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#define NS_SAP (1)
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#define NS_NDS (2)
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#define NS_TCPIP_LOCAL (10)
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#define NS_TCPIP_HOSTS (11)
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#define NS_DNS (12)
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#define NS_NETBT (13)
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#define NS_WINS (14)
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#define NS_NBP (20)
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#define NS_MS (30)
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#define NS_STDA (31)
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#define NS_NTDS (32)
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#define NS_X500 (40)
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#define NS_NIS (41)
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for example, setting ExcludedProviders to "1" "12" means that
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GetAddressByName() will not attempt to use SAP or DNS when doing
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typical name resolution operations.
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ProviderOrder: a REG_MULTI_SZ that contains strings corresponding to
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keys under CurrentControlSet\Services. these keys must have a
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ServiceProvider subkey which provides information about the name
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space provider, especially Class and ProviderPath values.
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**** the following values are relevent to TCP/IP name resolution
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(gethostbyname()) and the GetAddressByName() API. under
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Services\Tcpip\ServiceProvider:
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Class, REG_DWORD, default = 8. should never change--this indicates
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that TCPIP is a name service provider.
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DnsPriority, REG_DWORD, default = 0x7D0
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HostsPriority, REG_DWORD, default = 0x1F4
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LocalPriority, REG_DWORD, default = 0x1F3
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NetbtPriority, REG_DWORD, default = 0x7D1
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these priority values are used to determine the order of name
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resolutions. low priority mechanisms are used first, so the default
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order is local, hosts, dns, netbt. if someone wants a different name
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resolution order, readjust the priority values as needed. note that
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values under 1000 decimal are considered "fast" name resolution
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providers, so putting network-based resolution mechanisms like dns
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and netbt at values under 1000 may have weird effects.
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Name, REG_SZ, default = "TCP/IP"
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no need to change.
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ProviderPath, REG_SZ, default = "%SystemRoot%\System32\wsock32.dll"
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points to the dll that does tcpip name resolution. there is no need
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to change this.
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**** there are other keys associated with netware name resolution.
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chuck chan will comment on their names and meaning.
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