OAL Elements for CeLog Event Tracking (Windows Embedded CE 6.0)
1/5/2010
OEMs can use programming elements in the OEM Adaptation Layer (OAL) to control event-tracking functionality. For background information about these elements, see CeLog Buffering Scheme.
On CPU types such as ARM and x86 that use hardware translation handling for look-aside buffer (TLB) misses, CeLog cannot record TLB miss counts. On other CPUs that use software TLB miss handling, such as SHx and MIPS, the kernel variable dwCeLogTLBMiss stores a count of TLB misses. The kernel TLB miss handler updates this variable on each TLB miss. A pointer to this variable is passed to your event-tracking library in the CeLogImportTable structure. For more information, see Retaining the dwCeLogTLBMiss Counter.
You can override the function pointers to point to new OEM functions. In this case, the new OEM functions must not make use of any system APIs, because using system APIs in this way can make the system hang.
For more information about relationship between function pointers and event tracking functions see CeLogExportTable.
When enabled, CeLog writes data it collects to a memory-mapped buffer in RAM. The size of the buffer that CeLog uses is set by the dwCeLogLargeBuf OAL variable. The value of dwCeLogLargeBuf is passed to the event-tracking library as part of the CeLogImportTable structure. You can choose to honor or disregard the value as you see fit.
CeLog also uses a small RAM buffer to temporarily hold interrupt data before it is written to the memory-mapped buffer. The size of the small buffer is set by the dwCeLogSmallBuf OAL variable, which is also passed to your event tracking library in the CeLogImportTable structure.
In Windows Embedded CE, the OAL variables dwCeLogLargeBuf and dwCeLogSmallBuf are not supported. For version of the operating system that support these variables, the following descriptions apply.**
See Also
Other Resources
Implementing a Custom Event Tracking Library
CeLog Event Tracking Reference
Developing an OEM Adaptation Layer