void DataFlash_File::_io_timer(void)
{
uint16_t _tail;
if (_write_fd == -1 || !_initialised) {
return;
}
uint16_t nbytes = BUF_AVAILABLE(_writebuf);
if (nbytes == 0) {
return;
}
uint32_t tnow = hal.scheduler->micros();
if (nbytes < 512 &&
tnow - _last_write_time < 2000000UL) {
// write in 512 byte chunks, but always write at least once
// per 2 seconds if data is available
return;
}
_last_write_time = tnow;
if (nbytes > 512) {
// be kind to the FAT PX4 filesystem
nbytes = 512;
}
if (_writebuf_head > _tail) {
// only write to the end of the buffer
nbytes = min(nbytes, _writebuf_size - _writebuf_head);
}
assert(_writebuf_head+nbytes <= _writebuf_size);
ssize_t nwritten = ::write(_write_fd, &_writebuf[_writebuf_head], nbytes);
if (nwritten <= 0) {
//hal.console->printf("DataFlash write: %d %d\n", (int)nwritten, (int)errno);
close(_write_fd);
_write_fd = -1;
_initialised = false;
} else {
BUF_ADVANCEHEAD(_writebuf, nwritten);
if (hal.scheduler->millis() - last_fsync_ms > 10000) {
last_fsync_ms = hal.scheduler->millis();
::fsync(_write_fd);
}
}
}
void DataFlash_File::_io_timer(void)
{
uint16_t _tail;
if (_write_fd == -1 || !_initialised || _open_error) {
return;
}
uint16_t nbytes = BUF_AVAILABLE(_writebuf);
if (nbytes == 0) {
return;
}
uint32_t tnow = hal.scheduler->micros();
if (nbytes < _writebuf_chunk &&
tnow - _last_write_time < 2000000UL) {
// write in 512 byte chunks, but always write at least once
// per 2 seconds if data is available
return;
}
perf_begin(_perf_write);
_last_write_time = tnow;
if (nbytes > _writebuf_chunk) {
// be kind to the FAT PX4 filesystem
nbytes = _writebuf_chunk;
}
if (_writebuf_head > _tail) {
// only write to the end of the buffer
nbytes = min(nbytes, _writebuf_size - _writebuf_head);
}
// try to align writes on a 512 byte boundary to avoid filesystem
// reads
if ((nbytes + _write_offset) % 512 != 0) {
uint32_t ofs = (nbytes + _write_offset) % 512;
if (ofs < nbytes) {
nbytes -= ofs;
}
}
assert(_writebuf_head+nbytes <= _writebuf_size);
ssize_t nwritten = ::write(_write_fd, &_writebuf[_writebuf_head], nbytes);
if (nwritten <= 0) {
perf_count(_perf_errors);
close(_write_fd);
_write_fd = -1;
_initialised = false;
} else {
_write_offset += nwritten;
/*
the best strategy for minimising corruption on microSD cards
seems to be to write in 4k chunks and fsync the file on each
chunk, ensuring the directory entry is updated after each
write.
*/
#if CONFIG_HAL_BOARD != HAL_BOARD_AVR_SITL
::fsync(_write_fd);
#endif
BUF_ADVANCEHEAD(_writebuf, nwritten);
}
perf_end(_perf_write);
}
