| Message ID | 20240210215147.77629-20-michael.zaidman@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Delegated to: | Jiri Kosina |
| Headers | show |
| Series | hid-ft260: Fixes for serial driver patch v4 | expand |
On Sat, Feb 10, 2024 at 11:51:47PM +0200, Michael Zaidman wrote: > Tx performance with the current buffer size of 256 bytes is lower when > the data length exceeds the xmit buf size. > > [134331.147978] ft260_uart_write: count: 288, len: 256 > [134331.157945] ft260_uart_write: count: 32, len: 32 > [134331.159977] ft260_uart_write: count: 288, len: 256 > [134331.169990] ft260_uart_write: count: 32, len: 32 > > 1. Increase the xmit buffer size to page size as used in the serial core > and other tty drivers. > > 2. Remove the xmit buffer fulness against the watermark checking and the > tty_wakeup calling in the ft260_uart_transmit_chars routine. This code is > taken from other drivers, but other drivers may call the routine from the > interrupt context. In our case, this condition is always True since xmit > buffer filling and emptying are serialized and done synchronously. > > Tested with picocom ASCII file transfer by 288-byte chunks at 921600 > bauds rate with above 20% performance improvement. > > Before: > 2821.7 Kbytes transferred at 47367 CPS... Done. > > After: > 2821.7 Kbytes transferred at 57788 CPS... Done. > Besides the performance improvement, it fixes the bug of outputting characters to the local terminal when local echo is disabled and printing every character twice with local echo enabled. > Signed-off-by: Michael Zaidman <michael.zaidman@gmail.com> > --- > drivers/hid/hid-ft260.c | 11 +++-------- > 1 file changed, 3 insertions(+), 8 deletions(-) > > diff --git a/drivers/hid/hid-ft260.c b/drivers/hid/hid-ft260.c > index 6b172bfa4f98..1188b8e09938 100644 > --- a/drivers/hid/hid-ft260.c > +++ b/drivers/hid/hid-ft260.c > @@ -308,8 +308,7 @@ enum { > #define FT260_UART_EN_PW_SAVE_BAUD (4800) > > #define UART_COUNT_MAX (4) /* Number of supported UARTs */ > -#define XMIT_FIFO_SIZE (256) > -#define TTY_WAKEUP_WATERMARK (XMIT_FIFO_SIZE / 2) > +#define XMIT_FIFO_SIZE (PAGE_SIZE) > > static const struct hid_device_id ft260_devices[] = { > { HID_USB_DEVICE(USB_VENDOR_ID_FUTURE_TECHNOLOGY, > @@ -1211,7 +1210,7 @@ static int ft260_uart_transmit_chars(struct ft260_device *port) > > len = kfifo_out_spinlocked(xmit, rep->data, len, &port->xmit_fifo_lock); > > - ret = ft260_hid_output_report(hdev, (u8 *)rep, len + sizeof(*rep)); > + ret = ft260_hid_output_report(hdev, (u8 *)rep, len + 2); > if (ret < 0) > goto tty_out; > > @@ -1219,10 +1218,6 @@ static int ft260_uart_transmit_chars(struct ft260_device *port) > port->icount.tx += len; > } while (data_len > 0); > > - len = kfifo_len(xmit); > - if ((XMIT_FIFO_SIZE - len) > TTY_WAKEUP_WATERMARK) > - tty_wakeup(tty); > - > ret = 0; > > tty_out:
diff --git a/drivers/hid/hid-ft260.c b/drivers/hid/hid-ft260.c index 6b172bfa4f98..1188b8e09938 100644 --- a/drivers/hid/hid-ft260.c +++ b/drivers/hid/hid-ft260.c @@ -308,8 +308,7 @@ enum { #define FT260_UART_EN_PW_SAVE_BAUD (4800) #define UART_COUNT_MAX (4) /* Number of supported UARTs */ -#define XMIT_FIFO_SIZE (256) -#define TTY_WAKEUP_WATERMARK (XMIT_FIFO_SIZE / 2) +#define XMIT_FIFO_SIZE (PAGE_SIZE) static const struct hid_device_id ft260_devices[] = { { HID_USB_DEVICE(USB_VENDOR_ID_FUTURE_TECHNOLOGY, @@ -1211,7 +1210,7 @@ static int ft260_uart_transmit_chars(struct ft260_device *port) len = kfifo_out_spinlocked(xmit, rep->data, len, &port->xmit_fifo_lock); - ret = ft260_hid_output_report(hdev, (u8 *)rep, len + sizeof(*rep)); + ret = ft260_hid_output_report(hdev, (u8 *)rep, len + 2); if (ret < 0) goto tty_out; @@ -1219,10 +1218,6 @@ static int ft260_uart_transmit_chars(struct ft260_device *port) port->icount.tx += len; } while (data_len > 0); - len = kfifo_len(xmit); - if ((XMIT_FIFO_SIZE - len) > TTY_WAKEUP_WATERMARK) - tty_wakeup(tty); - ret = 0; tty_out: @@ -1546,7 +1541,7 @@ static int ft260_uart_port_activate(struct tty_port *tport, struct tty_struct *t if (baudrate > FT260_UART_EN_PW_SAVE_BAUD) ft260_uart_wakeup_workaraund_enable(port, true); - ft260_dbg("configurd baudrate = %d", baudrate); + ft260_dbg("configured baudrate = %d", baudrate); mod_timer(&port->wakeup_timer, jiffies + msecs_to_jiffies(FT260_WAKEUP_NEEDED_AFTER_MS));
Tx performance with the current buffer size of 256 bytes is lower when the data length exceeds the xmit buf size. [134331.147978] ft260_uart_write: count: 288, len: 256 [134331.157945] ft260_uart_write: count: 32, len: 32 [134331.159977] ft260_uart_write: count: 288, len: 256 [134331.169990] ft260_uart_write: count: 32, len: 32 1. Increase the xmit buffer size to page size as used in the serial core and other tty drivers. 2. Remove the xmit buffer fulness against the watermark checking and the tty_wakeup calling in the ft260_uart_transmit_chars routine. This code is taken from other drivers, but other drivers may call the routine from the interrupt context. In our case, this condition is always True since xmit buffer filling and emptying are serialized and done synchronously. Tested with picocom ASCII file transfer by 288-byte chunks at 921600 bauds rate with above 20% performance improvement. Before: 2821.7 Kbytes transferred at 47367 CPS... Done. After: 2821.7 Kbytes transferred at 57788 CPS... Done. Signed-off-by: Michael Zaidman <michael.zaidman@gmail.com> --- drivers/hid/hid-ft260.c | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-)