On Time RTOS-32 Documentation

RTFiles-32 Programming Manual

RTFiles-32 Reference Manual

General File I/O

Information about Files

File Attributes

File Name Operations

Disk and Volume Management

Miscellaneous File Functions

Raw I/O Functions

Functions for Debugging

Function RTFBufferInfo

Function RTFAddBuffers

Function RTFDumpFileTable

Function RTFSetMessageHandler

Function RTFDiagMessage

Device Dependent Functions

Obsolete Functions

Disk Device Driver API

MTD Device Driver API

RTFiles-32 Error Codes

Code Page Reference

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Function RTFBufferInfo

RTFBufferInfo returns information about RTFiles-32's internal buffer cache:

void RTFBufferInfo(RTFBufferStatistic * BufferInfo);

Parameters

BufferInfo

Pointer to structure RTFBufferStatistic defined in Rtfiles.h:

typedef struct { 

   DWORD TotalBuffers, 
         ValidBuffers, 
         DirtyBuffers, 
         MaxDirtyBuffers, 

         PhysicalBufferReads, 
         CachedBufferReads, 
         BuffersDiscarded, 
         CacheHits, 

         PhysicalBufferWrites, 
         CachedBufferWrites, 
         AsynchBufferFlushs, 

         UnbufferedReads, 
         UnbufferedWrites; 

} RTFBufferStatistic;

The counters contain the following values:

Value	Meaning
TotalBuffers	The number of available sector buffers. See Configuring RTFiles-32, section RTFiles-32 Data Tables for information on how to change the number of buffers.
ValidBuffers	The number of buffers currently holding valid data.
DirtyBuffers	The number of buffers currently holding data which has not yet been written to disk. This value must be 0 when all files are closed.
MaxDirtyBuffers	The maximum number of dirty buffers at any one time since program startup. This value should always be less than TotalBuffers. If it is not, consider increasing the number of buffers or avoid excessive use of device flag RTF_DEVICE_LAZY_WRITE or RTFOpen flag RTF_LAZY_DATA. When all buffers are dirty, RTFiles-32 may fail file I/O operations with error RTF_OUT_OF_BUFFERS, since it is not always possible to flush buffers when a new buffer is required.
PhysicalBufferReads	The number of sectors read from disk into a buffer since program start.
CachedBufferReads	The number of times RTFiles-32 required a sector of data and the required sector was found in the buffer cache (cache hits).
BuffersDiscarded	The number of times RTFiles-32 had to discard a valid buffer to accommodate a new sector. When a discarded sector is required at a later time, it must be reread from disk.
CacheHits	A percentage value indicating buffer cache efficiency. This value is calculated as 100 * CachedBufferReads / PhysicalBufferReads + CachedBufferReads).
PhysicalBufferWrites	The number of times RTFiles-32 has flushed a buffer to disk.
CachedBufferWrites	The number of times RTFiles-32 has modified the data in a dirty buffer. Such buffers are either still present in the cache as dirty buffers or they have been flushed at a later time.
AsynchBufferFlushs	The number of times a buffer was flushed to disk even though it had been modified in an earlier RTFiles-32 API function call. Such asynchronous buffer flushes will not occur if all files are opened with flag RTF_COMMITTED.
UnbufferedReads	The number of sectors read from disk, bypassing RTFiles-32's buffer cache. Such reads occur when the application reads large blocks of data containing complete sectors.
UnbufferedWrites	The number of sectors written to disk, bypassing RTFiles-32's buffer cache. Such writes occur when the application writes large blocks of data containing complete sectors.

Function RTFBufferInfo never fails and does not return a value. All counters start with 0 at program start.

Left Functions for Debugging

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