Detailed Description

This file implements text logging.

Uses a queue of buffers so that the expensive printf operation doesn't require exclusive access (ie, global system lock) to log. In the past there have been serious performance problems caused by heavy logging on a low priority thread that blocks the rest of the system running (trigger errors, etc).

Uses ChibiOS message queues to maintain one queue of free buffers, and one queue of used buffers. When a thread wants to write, it acquires a free buffer, prints to it, and pushes it in to the used queue. A dedicated thread then dequeues and writes lines from the used buffer in to the large output buffer.

Later, the binary TS thread will request access to the output log buffer for reading, so a lock is taken, buffers, swapped, and the back buffer returned. This blocks neither output nor logging in any case, as each operation operates on a different buffer.

Date: Mar 8, 2015, heavily revised April 2021

Author: Andrey Belomutskiy, (c) 2012-2021; Matthew Kennedy

Definition in file loggingcentral.cpp.

Namespaces
namespace	priv

Typedefs
using	LB = LogBuffer< DL_OUTPUT_BUFFER >

Functions
const char *	swapOutputBuffers (size_t *actualOutputBufferSize)

void	startLoggingProcessor ()

void	priv::efiPrintfInternal (const char *format,...)

void	scheduleLogging (Logging *logging)

Variables
chibios_rt::Mutex	logBufferMutex

LB	buffers [2]

LB *	writeBuffer = &buffers[0]

LB *	readBuffer = &buffers[1]

constexpr size_t	lineBufferCount = 24

static LogLineBuffer	lineBuffers [lineBufferCount]

static chibios_rt::Mailbox< LogLineBuffer *, lineBufferCount >	freeBuffers

static chibios_rt::Mailbox< LogLineBuffer *, lineBufferCount >	filledBuffers

static LoggingBufferFlusher	lbf

bool	verboseMode

Typedef Documentation

◆ LB

using LB = LogBuffer<DL_OUTPUT_BUFFER>

Definition at line 83 of file loggingcentral.cpp.

Function Documentation

◆ scheduleLogging()

void scheduleLogging ( Logging * logging )

This method appends the content of specified thread-local logger into the global buffer of logging content.

This is a legacy function, most normal logging should use efiPrintf

Definition at line 237 of file loggingcentral.cpp.

                                       {
#if (EFI_PROD_CODE || EFI_SIMULATOR) && EFI_TEXT_LOGGING
    // Lock the buffer mutex - inhibit buffer swaps while writing
    {
        chibios_rt::MutexLocker lock(logBufferMutex);
 
        writeBuffer->writeLogger(logging);
    }
 
    // Reset the logging now that it's been written out
    logging->reset();
#endif
}

Referenced by printHistogram(), WaveChart::publish(), and updateDevConsoleState().

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◆ startLoggingProcessor()

void startLoggingProcessor ( )

Definition at line 159 of file loggingcentral.cpp.

                             {
    // Push all buffers in to the free queue
    for (size_t i = 0; i < lineBufferCount; i++) {
        freeBuffers.post(&lineBuffers[i], TIME_INFINITE);
    }
 
    // Start processing used buffers
    lbf.start();
}

Referenced by runRusEfi().

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◆ swapOutputBuffers()

const char * swapOutputBuffers ( size_t * actualOutputBufferSize )

Actual communication layer invokes this method when it's ready to send some data out

Returns: pointer to the buffer which should be print to console

Definition at line 93 of file loggingcentral.cpp.

                                                              {
    {
        chibios_rt::MutexLocker lock(logBufferMutex);
 
        // Swap buffers under lock
        auto temp = writeBuffer;
        writeBuffer = readBuffer;
        readBuffer = temp;
 
        // Reset the front buffer - it's now empty
        writeBuffer->reset();
    }
 
    *actualOutputBufferSize = readBuffer->length();
#if EFI_ENABLE_ASSERTS
    size_t expectedOutputSize = std::strlen(readBuffer->get());
 
    // Check that the actual length of the buffer matches the expected length of how much we thought we wrote
    if (*actualOutputBufferSize != expectedOutputSize) {
        firmwareError(ObdCode::ERROR_LOGGING_SIZE_CALC, "lsize mismatch %d vs strlen %d", *actualOutputBufferSize, expectedOutputSize);
 
        return nullptr;
    }
#endif /* EFI_ENABLE_ASSERTS */
    return readBuffer->get();
}