Re: [Qemu-devel] [PATCH 3/3] ati-vga: Silence some noisy traces

[Gerd Hoffmann <kraxel@redhat.com>]

On Fri, Aug 16, 2019 at 12:18:09AM +0200, BALATON Zoltan wrote:
> Some registers are accessed very frequently so exclude these from
> traces to avoid flooding output with a lot of trace logs when traces
> are enabled thus helping debugging.
> 
> Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
> ---
>  hw/display/ati.c | 18 ++++++++++++++++--
>  1 file changed, 16 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/display/ati.c b/hw/display/ati.c
> index 5e2c4ba4aa..36d2a75f71 100644
> --- a/hw/display/ati.c
> +++ b/hw/display/ati.c
> @@ -489,7 +489,14 @@ static uint64_t ati_mm_read(void *opaque, hwaddr addr, unsigned int size)
>      default:
>          break;
>      }
> -    if (addr < CUR_OFFSET || addr > CUR_CLR1 || ATI_DEBUG_HW_CURSOR) {
> +    if ((addr < CUR_OFFSET || addr > CUR_CLR1 + 3 || (ATI_DEBUG_HW_CURSOR &&
> +        (addr >= CUR_OFFSET && addr <= CUR_CLR1 + 3))) &&
> +        (addr < GEN_INT_CNTL || addr > GEN_INT_STATUS + 3) &&
> +        (addr < GPIO_MONID || addr > GPIO_MONID + 3) &&
> +        (addr < AMCGPIO_MASK_MIR || addr > AMCGPIO_EN_MIR + 3) &&
> +        (addr < 0x908 || addr > 0x90f) && (addr < 0xc4c || addr > 0xc53) &&
> +        addr != RBBM_STATUS && addr != 0x1714 &&
> +        addr != 0x7b8 && addr > MM_DATA + 3) {
>          trace_ati_mm_read(size, addr, ati_reg_name(addr & ~3ULL), val);

I'd suggest to split the trace_ati_mm_read tracepoint, so this can be
tweaked at runtime without patching the source code.

One tracepoint per register is probably a bit over the top.  Grouping
registers by function (i2c, crtc, irq, cursor, ...) looks useful to me.

cheers,
  Gerd