Separate the head & commit indices from the tail index to avoid cache-line contention (so called 'false-sharing') between concurrent threads.
Signed-off-by: Peter Hurley <[email protected]> --- drivers/tty/n_tty.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index eb20777..aa63cd3 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -90,6 +90,8 @@ struct n_tty_data { /* producer-published */ size_t read_head; size_t canon_head; + size_t echo_head; + size_t echo_commit; DECLARE_BITMAP(process_char_map, 256); /* private to n_tty_receive_overrun (single-threaded) */ @@ -105,20 +107,17 @@ struct n_tty_data { /* shared by producer and consumer */ char *read_buf; DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE); + unsigned char *echo_buf; int minimum_to_wake; /* consumer-published */ size_t read_tail; - unsigned char *echo_buf; - size_t echo_head; - size_t echo_tail; - size_t echo_commit; - /* protected by output lock */ unsigned int column; unsigned int canon_column; + size_t echo_tail; struct mutex atomic_read_lock; struct mutex output_lock; -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
