[pulseaudio-discuss] [PATCH RFCv3 50/51] alsa: Precompute max_frames

[David Henningsson]

On 2014-11-05 00:26, Peter Meerwald wrote:
> From: Peter Meerwald <p.meerwald at bct-electronic.com>
>
> max_frames is the mempool's maximum block size in frames

I would probably call the variable "frames_per_block" or something, 
would be more clear

Also one could write code as

frames = PA_MIN( /* other value */,  u->frames_per_block)

>
> Signed-off-by: Peter Meerwald <pmeerw at pmeerw.net>
> ---
>   src/modules/alsa/alsa-sink.c   | 7 +++++--
>   src/modules/alsa/alsa-source.c | 7 +++++--
>   2 files changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/src/modules/alsa/alsa-sink.c b/src/modules/alsa/alsa-sink.c
> index aab7ee7..a637462 100644
> --- a/src/modules/alsa/alsa-sink.c
> +++ b/src/modules/alsa/alsa-sink.c
> @@ -127,6 +127,8 @@ struct userdata {
>           watermark_dec_threshold,
>           rewind_safeguard;
>
> +    snd_pcm_uframes_t max_frames;
> +
>       pa_usec_t watermark_dec_not_before;
>       pa_usec_t min_latency_ref;
>       pa_usec_t tsched_watermark_usec;
> @@ -640,8 +642,8 @@ static int mmap_write(struct userdata *u, pa_usec_t *sleep_usec, bool polled, bo
>               }
>
>               /* Make sure that if these memblocks need to be copied they will fit into one slot */
> -            if (frames > pa_mempool_block_size_max(u->core->mempool)/u->frame_size)
> -                frames = pa_mempool_block_size_max(u->core->mempool)/u->frame_size;
> +            if (frames > u->max_frames)
> +                frames = u->max_frames;
>
>               if (!after_avail && frames == 0)
>                   break;
> @@ -2330,6 +2332,7 @@ pa_sink *pa_alsa_sink_new(pa_module *m, pa_modargs *ma, const char*driver, pa_ca
>       pa_sink_set_rtpoll(u->sink, u->rtpoll);
>
>       u->frame_size = frame_size;
> +    u->max_frames = pa_mempool_block_size_max(m->core->mempool) / frame_size;
>       u->fragment_size = frag_size = (size_t) (period_frames * frame_size);
>       u->hwbuf_size = buffer_size = (size_t) (buffer_frames * frame_size);
>       pa_cvolume_mute(&u->hardware_volume, u->sink->sample_spec.channels);
> diff --git a/src/modules/alsa/alsa-source.c b/src/modules/alsa/alsa-source.c
> index ac88e4b..8a027b0 100644
> --- a/src/modules/alsa/alsa-source.c
> +++ b/src/modules/alsa/alsa-source.c
> @@ -116,6 +116,8 @@ struct userdata {
>           watermark_inc_threshold,
>           watermark_dec_threshold;
>
> +    snd_pcm_uframes_t max_frames;
> +
>       pa_usec_t watermark_dec_not_before;
>       pa_usec_t min_latency_ref;
>       pa_usec_t tsched_watermark_usec;
> @@ -591,8 +593,8 @@ static int mmap_read(struct userdata *u, pa_usec_t *sleep_usec, bool polled, boo
>               }
>
>               /* Make sure that if these memblocks need to be copied they will fit into one slot */
> -            if (frames > pa_mempool_block_size_max(u->core->mempool)/u->frame_size)
> -                frames = pa_mempool_block_size_max(u->core->mempool)/u->frame_size;
> +            if (frames > u->max_frames)
> +                frames = u->max_frames;
>
>               if (!after_avail && frames == 0)
>                   break;
> @@ -2035,6 +2037,7 @@ pa_source *pa_alsa_source_new(pa_module *m, pa_modargs *ma, const char*driver, p
>       pa_source_set_rtpoll(u->source, u->rtpoll);
>
>       u->frame_size = frame_size;
> +    u->max_frames = pa_mempool_block_size_max(m->core->mempool) / frame_size;
>       u->fragment_size = frag_size = (size_t) (period_frames * frame_size);
>       u->hwbuf_size = buffer_size = (size_t) (buffer_frames * frame_size);
>       pa_cvolume_mute(&u->hardware_volume, u->source->sample_spec.channels);
>

-- 
David Henningsson, Canonical Ltd.
https://launchpad.net/~diwic