From: Tim Newsome Date: Fri, 28 May 2021 20:38:50 +0000 (-0700) Subject: Add remote bitbang write buffer. X-Git-Tag: v0.12.0-rc1~689 X-Git-Url: https://review.openocd.org/gitweb?p=openocd.git;a=commitdiff_plain;h=f2958fc04bd879393fa743860478834e234f05d0 Add remote bitbang write buffer. Change 7dd323b26 reduced remote bitbang performance a lot. This change gets most of that performance back again, by reintroducing a write buffer. Performance numbers collected using DebugBreakpoint test from riscv-tests/debug against a single 64-bit spike (RISC-V simulator) instance. (Ubuntu 20.04.2, AMD Ryzen 5 3600) Before Windows support was added: 3.09s After Windows support was added: 12.67s After this change: 4.69s Signed-off-by: Tim Newsome Change-Id: I72ff4912cbbf316a30ef065e5b8f461a555f06cc Reviewed-on: http://openocd.zylin.com/6283 Tested-by: jenkins Reviewed-by: Jan Matyas Reviewed-by: Tarek BOCHKATI Reviewed-by: Antonio Borneo --- diff --git a/src/jtag/drivers/remote_bitbang.c b/src/jtag/drivers/remote_bitbang.c index f7b88303ba..57f0c6e071 100644 --- a/src/jtag/drivers/remote_bitbang.c +++ b/src/jtag/drivers/remote_bitbang.c @@ -36,17 +36,19 @@ static char *remote_bitbang_host; static char *remote_bitbang_port; static int remote_bitbang_fd; +static uint8_t remote_bitbang_send_buf[512]; +static unsigned int remote_bitbang_send_buf_used; /* Circular buffer. When start == end, the buffer is empty. */ -static char remote_bitbang_buf[64]; -static unsigned remote_bitbang_start; -static unsigned remote_bitbang_end; +static char remote_bitbang_recv_buf[64]; +static unsigned int remote_bitbang_recv_buf_start; +static unsigned int remote_bitbang_recv_buf_end; -static int remote_bitbang_buf_full(void) +static bool remote_bitbang_buf_full(void) { - return remote_bitbang_end == - ((remote_bitbang_start + sizeof(remote_bitbang_buf) - 1) % - sizeof(remote_bitbang_buf)); + return remote_bitbang_recv_buf_end == + ((remote_bitbang_recv_buf_start + sizeof(remote_bitbang_recv_buf) - 1) % + sizeof(remote_bitbang_recv_buf)); } /* Read any incoming data, placing it into the buffer. */ @@ -54,23 +56,23 @@ static int remote_bitbang_fill_buf(void) { socket_nonblock(remote_bitbang_fd); while (!remote_bitbang_buf_full()) { - unsigned contiguous_available_space; - if (remote_bitbang_end >= remote_bitbang_start) { - contiguous_available_space = sizeof(remote_bitbang_buf) - - remote_bitbang_end; - if (remote_bitbang_start == 0) + unsigned int contiguous_available_space; + if (remote_bitbang_recv_buf_end >= remote_bitbang_recv_buf_start) { + contiguous_available_space = sizeof(remote_bitbang_recv_buf) - + remote_bitbang_recv_buf_end; + if (remote_bitbang_recv_buf_start == 0) contiguous_available_space -= 1; } else { - contiguous_available_space = remote_bitbang_start - - remote_bitbang_end - 1; + contiguous_available_space = remote_bitbang_recv_buf_start - + remote_bitbang_recv_buf_end - 1; } ssize_t count = read_socket(remote_bitbang_fd, - remote_bitbang_buf + remote_bitbang_end, + remote_bitbang_recv_buf + remote_bitbang_recv_buf_end, contiguous_available_space); if (count > 0) { - remote_bitbang_end += count; - if (remote_bitbang_end == sizeof(remote_bitbang_buf)) - remote_bitbang_end = 0; + remote_bitbang_recv_buf_end += count; + if (remote_bitbang_recv_buf_end == sizeof(remote_bitbang_recv_buf)) + remote_bitbang_recv_buf_end = 0; } else if (count == 0) { return ERROR_OK; } else if (count < 0) { @@ -90,20 +92,43 @@ static int remote_bitbang_fill_buf(void) return ERROR_OK; } -static int remote_bitbang_putc(int c) +static int remote_bitbang_flush(void) { - char buf = c; - ssize_t count = write_socket(remote_bitbang_fd, &buf, sizeof(buf)); - if (count < 0) { - log_socket_error("remote_bitbang_putc"); - return ERROR_FAIL; + if (remote_bitbang_send_buf_used <= 0) + return ERROR_OK; + + unsigned int offset = 0; + while (offset < remote_bitbang_send_buf_used) { + ssize_t written = write_socket(remote_bitbang_fd, remote_bitbang_send_buf + offset, + remote_bitbang_send_buf_used - offset); + if (written < 0) { + log_socket_error("remote_bitbang_putc"); + remote_bitbang_send_buf_used = 0; + return ERROR_FAIL; + } + offset += written; } + remote_bitbang_send_buf_used = 0; + return ERROR_OK; +} + +typedef enum { + NO_FLUSH, + FLUSH_SEND_BUF +} flush_bool_t; + +static int remote_bitbang_queue(int c, flush_bool_t flush) +{ + remote_bitbang_send_buf[remote_bitbang_send_buf_used++] = c; + if (flush == FLUSH_SEND_BUF || + remote_bitbang_send_buf_used >= ARRAY_SIZE(remote_bitbang_send_buf)) + return remote_bitbang_flush(); return ERROR_OK; } static int remote_bitbang_quit(void) { - if (remote_bitbang_putc('Q') == ERROR_FAIL) + if (remote_bitbang_queue('Q', FLUSH_SEND_BUF) == ERROR_FAIL) return ERROR_FAIL; if (close_socket(remote_bitbang_fd) != 0) { @@ -135,6 +160,9 @@ static bb_value_t char_to_int(int c) /* Get the next read response. */ static bb_value_t remote_bitbang_rread(void) { + if (remote_bitbang_flush() != ERROR_OK) + return ERROR_FAIL; + /* Enable blocking access. */ socket_block(remote_bitbang_fd); char c; @@ -154,15 +182,19 @@ static int remote_bitbang_sample(void) if (remote_bitbang_fill_buf() != ERROR_OK) return ERROR_FAIL; assert(!remote_bitbang_buf_full()); - return remote_bitbang_putc('R'); + return remote_bitbang_queue('R', NO_FLUSH); } static bb_value_t remote_bitbang_read_sample(void) { - if (remote_bitbang_start != remote_bitbang_end) { - int c = remote_bitbang_buf[remote_bitbang_start]; - remote_bitbang_start = - (remote_bitbang_start + 1) % sizeof(remote_bitbang_buf); + if (remote_bitbang_recv_buf_start == remote_bitbang_recv_buf_end) { + if (remote_bitbang_fill_buf() != ERROR_OK) + return ERROR_FAIL; + } + if (remote_bitbang_recv_buf_start != remote_bitbang_recv_buf_end) { + int c = remote_bitbang_recv_buf[remote_bitbang_recv_buf_start]; + remote_bitbang_recv_buf_start = + (remote_bitbang_recv_buf_start + 1) % sizeof(remote_bitbang_recv_buf); return char_to_int(c); } return remote_bitbang_rread(); @@ -171,23 +203,25 @@ static bb_value_t remote_bitbang_read_sample(void) static int remote_bitbang_write(int tck, int tms, int tdi) { char c = '0' + ((tck ? 0x4 : 0x0) | (tms ? 0x2 : 0x0) | (tdi ? 0x1 : 0x0)); - return remote_bitbang_putc(c); + return remote_bitbang_queue(c, NO_FLUSH); } static int remote_bitbang_reset(int trst, int srst) { char c = 'r' + ((trst ? 0x2 : 0x0) | (srst ? 0x1 : 0x0)); - return remote_bitbang_putc(c); + /* Always flush the send buffer on reset, because the reset call need not be + * followed by jtag_execute_queue(). */ + return remote_bitbang_queue(c, FLUSH_SEND_BUF); } static int remote_bitbang_blink(int on) { char c = on ? 'B' : 'b'; - return remote_bitbang_putc(c); + return remote_bitbang_queue(c, FLUSH_SEND_BUF); } static struct bitbang_interface remote_bitbang_bitbang = { - .buf_size = sizeof(remote_bitbang_buf) - 1, + .buf_size = sizeof(remote_bitbang_recv_buf) - 1, .sample = &remote_bitbang_sample, .read_sample = &remote_bitbang_read_sample, .write = &remote_bitbang_write, @@ -268,8 +302,8 @@ static int remote_bitbang_init(void) { bitbang_interface = &remote_bitbang_bitbang; - remote_bitbang_start = 0; - remote_bitbang_end = 0; + remote_bitbang_recv_buf_start = 0; + remote_bitbang_recv_buf_end = 0; LOG_INFO("Initializing remote_bitbang driver"); if (remote_bitbang_port == NULL) @@ -326,8 +360,23 @@ static const struct command_registration remote_bitbang_command_handlers[] = { COMMAND_REGISTRATION_DONE, }; +static int remote_bitbang_execute_queue(void) +{ + /* safety: the send buffer must be empty, no leftover characters from + * previous transactions */ + assert(remote_bitbang_send_buf_used == 0); + + /* process the JTAG command queue */ + int ret = bitbang_execute_queue(); + if (ret != ERROR_OK) + return ret; + + /* flush not-yet-sent characters, if any */ + return remote_bitbang_flush(); +} + static struct jtag_interface remote_bitbang_interface = { - .execute_queue = &bitbang_execute_queue, + .execute_queue = &remote_bitbang_execute_queue, }; struct adapter_driver remote_bitbang_adapter_driver = {