Replace SNDRV_DMA_TYPE_DEV by SNDRV_DMA_TYPE_NONCOHERENT for pcm buffer allocation. We measured about 18x performance improvement when accessing the snd_pcm_mmap() buffer from userspace.
Eg: aarch64 with internal speaker == SNDRV_DMA_TYPE_DEV frames_per_second=66.4557M/s max_time_per_4096_frames=106.094u time_per_4096_frames=61.6351us
SNDRV_DMA_TYPE_NONCOHERENT frames_per_second=1028.58M/s max_time_per_4096_frames=20.312u time_per_4096_frames=3.98221us
Signed-off-by: Judy Hsiao judyhsiao@chromium.org
---
sound/soc/qcom/lpass-platform.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/soc/qcom/lpass-platform.c b/sound/soc/qcom/lpass-platform.c index b41ab7a321ae..ef5cb40b2d9b 100644 --- a/sound/soc/qcom/lpass-platform.c +++ b/sound/soc/qcom/lpass-platform.c @@ -1181,7 +1181,7 @@ static int lpass_platform_pcm_new(struct snd_soc_component *component, if (is_cdc_dma_port(dai_id)) return lpass_platform_prealloc_cdc_dma_buffer(component, pcm, dai_id);
- return snd_pcm_set_fixed_buffer_all(pcm, SNDRV_DMA_TYPE_DEV, + return snd_pcm_set_fixed_buffer_all(pcm, SNDRV_DMA_TYPE_NONCOHERENT, component->dev, size); }