metalsvm/documentation/text/config.dox

/**
 * @file config.dox
 * @page config MetalSVM feature configuration files
 *
 * @section main_config MetalSVM's main configuration file
 *
 * MetalSVM's configuration parameters and some features can be configured/activated 
 * in the central configuration file located at \c include/metalsvm/config.h.
 *
 * The `config.h` is a usual C header file and the configuration items are usual 
 * C preprocessor-definitions like the following:
 * \code
#define CONFIGURATION_PARAMETER 123value    /* A parameter with a value */
#define FEATURE_A                           /* An activated feature */
//#define FEATURE_B                         /* A deactivated feature */\endcode
 *
 * Just like the example suggests, features are deactivated by commenting them out.
 *
 * If you boot MetalSVM on the Intel SCC, you need to \b deactivate `CONFIG_PCI`,
 * `CONFIG_VGA`, `CONFIG_KEYBOARD`, and `CONFIG_MULTIBOOT` and 
 * \b activate `CONFIG_ROCKCREEK`. Set `CACHE_LINE` to 32.\n
 * Activate `CONFIG_UART` if you are going to use software-UART and deactivate it if
 * not, to avoid unnecessary traffic.
 *
 * @section lwip_config LwIP configuration flags
 *
 * The networking subsystem, based on LwIP, can of course be influenced by various
 * feature flags.
 * 
 * MetalSVM overrides various standard settings in `lwip/src/include/lwipopts.h`.
 *
 * If you chose `CONFIG_ROCKCREEK`, this leads to deactivation of `LWIP_DHCP`.
 * 
 * If you chose `CONFIG_TICKLESS`, `NO_SYS` will be activated and the following 
 * are deactivated: `LWIP_SOCKET`, `LWIP_NETCON`, `LWIP_NETIF_API`.
 *
 * Another interesting feature is `LWIP_CHECKSUM_ON_COPY`. Deactivating it leads
 * to higher network throughput for on-die communication.
 *
 * See LwIP documentation for more specific information about the individual effects of
 * manipulating the LwIP configuration flags/values.
 *
 * @section mmnif_config MMNIF configuration flags
 * Several flags in the file `drivers/net/mmnif.c` file influence the memory 
 * mapped network interface's performance:
 * 
 * - `USE_CACHE`: activates the cache for the memory mapped buffer region. 
 *  This improves the performance.
 * - `USE_MPB`: If activated, the buffer will be mapped onto the SCC's special MPB, 
 *   which improves the performance drastically.
 *
 * @section svm_config SVM configuration flags
 * 
 * Although the choice between different shared memory release consistency models 
 * is configured in the application code, there are 2 flags which influence the SVM 
 * implementation. These are located in `arch/x86/mm/svm.c`:
 *
 * - `USE_PERFCOUNTERS`: Performance counters will help evaluating the performance 
 *   of the SVM implementation within the kernel. Deactivate to omit overhead.
 *
 * - `USE_RESP_MAIL`: Whenever a core requests access to a page it is not the owner 
 *   of, it sends an interrupt to the owner. The requesting core will then wait for the mail
 *   indicating that it has become the new owner of the particular page, spinning on its mailbox.
 *   When `USE_RESP_MAIL` is activated, other interrupts will be deactivated until the response
 *   has arrived.
 * 
 *
 */