Hi Shimoda-san,
On Mon, May 29, 2023 at 10:08 AM Yoshihiro Shimoda
<yoshihiro.shimoda.uh@xxxxxxxxxxx> wrote:
> Use per-queue rate limiter instead of global rate limiter. Otherwise
> TX performance will be low when we use multiple ports at the same time.
>
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
Thanks for your patch!
> --- a/drivers/net/ethernet/renesas/rswitch.c
> +++ b/drivers/net/ethernet/renesas/rswitch.c
> @@ -156,22 +156,31 @@ static int rswitch_gwca_axi_ram_reset(struct rswitch_private *priv)
> return rswitch_reg_wait(priv->addr, GWARIRM, GWARIRM_ARR, GWARIRM_ARR);
> }
>
> -static void rswitch_gwca_set_rate_limit(struct rswitch_private *priv, int rate)
> +static void rswitch_gwca_set_rate_limit(struct rswitch_private *priv,
> + struct rswitch_gwca_queue *txq)
> {
> - u32 gwgrlulc, gwgrlc;
> + u64 period_ps;
> + unsigned long rate;
> + u32 gwrlc;
>
> - switch (rate) {
> - case 1000:
> - gwgrlulc = 0x0000005f;
> - gwgrlc = 0x00010260;
> - break;
> - default:
> - dev_err(&priv->pdev->dev, "%s: This rate is not supported (%d)\n", __func__, rate);
> - return;
> - }
> + rate = clk_get_rate(priv->aclk);
> + if (!rate)
> + rate = RSWITCH_ACLK_DEFAULT;
> +
> + period_ps = div64_u64(1000000000000ULL, rate);
div64_ul, as rate is unsigned long.
> +
> + /* GWRLC value = 256 * ACLK_period[ns] * maxBandwidth[Gbps] */
> + gwrlc = 256 * period_ps * txq->speed / 1000000;
This contains an open-coded 64-by-32 division, causing link failures
on 32-bit platforms, so you should use div_u64() instead. However,
because of the premultiplication by speed, which is 32-bit, you can
use the mul_u64_u32_div() helper.
Combining this with the calculation of period_ps above, you can simplify
this to:
gwrlc = div64_ul(256000000ULL * txq->speed, rate);
> +
> + /* To avoid overflow internally, the value should be 97% */
> + gwrlc = gwrlc * 97 / 100;
>
> - iowrite32(gwgrlulc, priv->addr + GWGRLULC);
> - iowrite32(gwgrlc, priv->addr + GWGRLC);
> + dev_dbg(&priv->pdev->dev,
> + "%s: index = %d, speed = %d, rate = %ld, gwrlc = %08x\n",
> + __func__, txq->index_trim, txq->speed, rate, gwrlc);
> +
> + iowrite32(GWRLULC_NOT_REQUIRED, priv->addr + GWRLULC(txq->index_trim));
> + iowrite32(gwrlc | GWRLC_RLE, priv->addr + GWRLC(txq->index_trim));
> }
>
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
