From: Andre Noll Date: Sun, 6 Nov 2011 11:14:17 +0000 (+0100) Subject: Merge branch 't/alsa_improvements' X-Git-Tag: v0.4.9~11 X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=commitdiff_plain;h=ff70d3f74c6116cf5b3c9a6708218788363efa7c;hp=e1f3c04146bff24c242101bb446a2528ee45214a Merge branch 't/alsa_improvements' --- diff --git a/NEWS b/NEWS index f50ffa3b..a79cc29f 100644 --- a/NEWS +++ b/NEWS @@ -12,7 +12,9 @@ - para_server prefaults the mmapped audio file to avoid delays on slow media. - A new test for the test-suite that exercises the - communication between para_server and para_audiod. + communication between para_server and para_audiod. + - The alsa writer eats up less CPU cycles when configured to + use the DMIX plugin. -------------------------------------- 0.4.8 (2011-08-19) "nested assignment" diff --git a/alsa_write.c b/alsa_write.c index 047e88f2..e741578c 100644 --- a/alsa_write.c +++ b/alsa_write.c @@ -36,10 +36,6 @@ struct private_alsa_write_data { snd_pcm_t *handle; /** Determined and set by alsa_init(). */ int bytes_per_frame; - /** The approximate maximum buffer duration in us. */ - unsigned buffer_time; - /* Number of frames that fit into the buffer. */ - snd_pcm_uframes_t buffer_frames; /** * The sample rate given by command line option or the decoder * of the writer node group. @@ -76,71 +72,119 @@ static int alsa_init(struct private_alsa_write_data *pad, snd_pcm_hw_params_t *hwparams; snd_pcm_sw_params_t *swparams; snd_pcm_uframes_t start_threshold, stop_threshold; - snd_pcm_uframes_t period_size; - int err; + snd_pcm_uframes_t buffer_size, period_size; + snd_output_t *log; + unsigned buffer_time; + int ret; + const char *msg; PARA_INFO_LOG("opening %s\n", conf->device_arg); - err = snd_pcm_open(&pad->handle, conf->device_arg, + msg = "unable to open pcm"; + ret = snd_pcm_open(&pad->handle, conf->device_arg, SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK); - if (err < 0) - return -E_PCM_OPEN; - + if (ret < 0) + goto fail; snd_pcm_hw_params_alloca(&hwparams); - snd_pcm_sw_params_alloca(&swparams); - if (snd_pcm_hw_params_any(pad->handle, hwparams) < 0) - return -E_BROKEN_CONF; - if (snd_pcm_hw_params_set_access(pad->handle, hwparams, - SND_PCM_ACCESS_RW_INTERLEAVED) < 0) - return -E_ACCESS_TYPE; - if (snd_pcm_hw_params_set_format(pad->handle, hwparams, - pad->sample_format) < 0) - return -E_SAMPLE_FORMAT; - if (snd_pcm_hw_params_set_channels(pad->handle, hwparams, - pad->channels) < 0) - return -E_CHANNEL_COUNT; - if (snd_pcm_hw_params_set_rate_near(pad->handle, hwparams, - &pad->sample_rate, NULL) < 0) - return -E_SET_RATE; - err = snd_pcm_hw_params_get_buffer_time_max(hwparams, - &pad->buffer_time, NULL); - if (err < 0 || !pad->buffer_time) - return -E_GET_BUFFER_TIME; - PARA_INFO_LOG("buffer time: %d\n", pad->buffer_time); - if (snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams, - &pad->buffer_time, NULL) < 0) - return -E_SET_BUFFER_TIME; - if (snd_pcm_hw_params(pad->handle, hwparams) < 0) - return -E_HW_PARAMS; + msg = "Broken alsa configuration"; + ret = snd_pcm_hw_params_any(pad->handle, hwparams); + if (ret < 0) + goto fail; + msg = "access type not available"; + ret = snd_pcm_hw_params_set_access(pad->handle, hwparams, + SND_PCM_ACCESS_RW_INTERLEAVED); + if (ret < 0) + goto fail; + msg = "sample format not available"; + ret = snd_pcm_hw_params_set_format(pad->handle, hwparams, + pad->sample_format); + if (ret < 0) + goto fail; + msg = "channels count not available"; + ret = snd_pcm_hw_params_set_channels(pad->handle, hwparams, + pad->channels); + if (ret < 0) + goto fail; + msg = "could not set sample rate"; + ret = snd_pcm_hw_params_set_rate_near(pad->handle, hwparams, + &pad->sample_rate, NULL); + if (ret < 0) + goto fail; + msg = "unable to get buffer time"; + ret = snd_pcm_hw_params_get_buffer_time_max(hwparams, &buffer_time, + NULL); + if (ret < 0 || buffer_time == 0) + goto fail; + msg = "could not set buffer time"; + ret = snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams, + &buffer_time, NULL); + if (ret < 0) + goto fail; + msg = "unable to install hw params"; + ret = snd_pcm_hw_params(pad->handle, hwparams); + if (ret < 0) + goto fail; snd_pcm_hw_params_get_period_size(hwparams, &period_size, NULL); - snd_pcm_hw_params_get_buffer_size(hwparams, &pad->buffer_frames); - PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", pad->buffer_frames, - period_size); - if (period_size == pad->buffer_frames) - return -E_BAD_PERIOD; + snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size); + msg = "period size equals buffer size"; + if (period_size == buffer_size) + goto fail; + + /* software parameter setup */ + snd_pcm_sw_params_alloca(&swparams); snd_pcm_sw_params_current(pad->handle, swparams); snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size); - if (pad->buffer_frames < 1) + if (buffer_size < 1) start_threshold = 1; else - start_threshold = PARA_MIN(pad->buffer_frames, + start_threshold = PARA_MIN(buffer_size, (snd_pcm_uframes_t)pad->sample_rate); - if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams, - start_threshold) < 0) - return -E_START_THRESHOLD; - stop_threshold = pad->buffer_frames; - if (snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams, - stop_threshold) < 0) - return -E_STOP_THRESHOLD; - if (snd_pcm_sw_params(pad->handle, swparams) < 0) - PARA_WARNING_LOG("unable to install sw params\n"); - pad->bytes_per_frame = snd_pcm_format_physical_width(pad->sample_format) - * pad->channels / 8; - if (pad->bytes_per_frame <= 0) - return -E_PHYSICAL_WIDTH; - PARA_INFO_LOG("bytes per frame: %d\n", pad->bytes_per_frame); - if (snd_pcm_nonblock(pad->handle, 1)) - PARA_ERROR_LOG("failed to set nonblock mode\n"); + msg = "could not set start threshold"; + ret = snd_pcm_sw_params_set_start_threshold(pad->handle, swparams, + start_threshold); + if (ret < 0) + goto fail; + stop_threshold = buffer_size; + msg = "could not set stop threshold"; + ret = snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams, + stop_threshold); + if (ret < 0) + goto fail; + msg = "unable to install sw params"; + ret = snd_pcm_sw_params(pad->handle, swparams); + if (ret < 0) + goto fail; + msg = "unable to determine bytes per frame"; + ret = snd_pcm_format_physical_width(pad->sample_format); + if (ret <= 0) + goto fail; + pad->bytes_per_frame = ret * pad->channels / 8; + msg = "failed to set alsa handle to nonblock mode"; + ret = snd_pcm_nonblock(pad->handle, 1); + if (ret < 0) + goto fail; + ret = snd_output_buffer_open(&log); + if (ret == 0) { + char *buf; + PARA_INFO_LOG("dumping alsa configuration\n"); + snd_pcm_dump(pad->handle, log); + snd_output_buffer_string(log, &buf); + for (;;) { + char *p = strchr(buf, '\n'); + if (!p) /* omit last output line, it's empty */ + break; + *p = '\0'; + PARA_INFO_LOG("%s\n", buf); + buf = p + 1; + } + snd_output_close(log); + } return 1; +fail: + if (ret < 0) + PARA_ERROR_LOG("%s: %s\n", msg, snd_strerror(-ret)); + else + PARA_ERROR_LOG("%s\n", msg); + return -E_ALSA; } static void alsa_write_pre_select(struct sched *s, struct task *t) @@ -164,8 +208,9 @@ static void alsa_write_pre_select(struct sched *s, struct task *t) } ret = snd_pcm_poll_descriptors(pad->handle, &pfd, 1); if (ret < 0) { - PARA_ERROR_LOG("%s\n", snd_strerror(-ret)); - t->error = -E_ALSA_POLL_FDS; + PARA_ERROR_LOG("could not get alsa poll fd: %s\n", + snd_strerror(-ret)); + t->error = -E_ALSA; return; } pad->poll_fd = pfd.fd; @@ -248,12 +293,23 @@ again: wn->min_iqs = pad->bytes_per_frame; goto again; } - if (pad->poll_fd >= 0 && !FD_ISSET(pad->poll_fd, &s->rfds)) + if (pad->poll_fd < 0 || !FD_ISSET(pad->poll_fd, &s->rfds)) return; frames = bytes / pad->bytes_per_frame; frames = snd_pcm_writei(pad->handle, data, frames); - if (frames == 0 || frames == -EAGAIN) + if (frames == 0 || frames == -EAGAIN) { + /* + * The alsa poll fd was ready for IO but we failed to write to + * the alsa handle. This means another event is pending. We + * don't care about that but we have to dispatch the event in + * order to avoid a busy loop. So we simply read from the poll + * fd. + */ + char buf[100]; + if (read(pad->poll_fd, buf, 100)) + do_nothing; return; + } if (frames > 0) { btr_consume(btrn, frames * pad->bytes_per_frame); goto again; @@ -263,8 +319,8 @@ again: snd_pcm_prepare(pad->handle); return; } - PARA_WARNING_LOG("%s\n", snd_strerror(-frames)); - ret = -E_ALSA_WRITE; + PARA_ERROR_LOG("alsa write error: %s\n", snd_strerror(-frames)); + ret = -E_ALSA; err: assert(ret < 0); btr_remove_node(btrn); diff --git a/error.h b/error.h index 65494131..b3eb7e6e 100644 --- a/error.h +++ b/error.h @@ -425,21 +425,7 @@ extern const char **para_errlist[]; #define ALSA_WRITE_ERRORS \ - PARA_ERROR(BROKEN_CONF, "Broken alsa configuration"), \ - PARA_ERROR(ACCESS_TYPE, "alsa access type not available"), \ - PARA_ERROR(SAMPLE_FORMAT, "sample format not available"), \ - PARA_ERROR(CHANNEL_COUNT, "channels count not available"), \ - PARA_ERROR(HW_PARAMS, "unable to install hw params"), \ - PARA_ERROR(BAD_PERIOD, "can not use period equal to buffer size"), \ - PARA_ERROR(ALSA_WRITE, "alsa write error"), \ - PARA_ERROR(PCM_OPEN, "unable to open pcm"), \ - PARA_ERROR(PHYSICAL_WIDTH, "unable to determine bytes per frame"), \ - PARA_ERROR(GET_BUFFER_TIME, "snd_pcm_hw_params_get_buffer_time_max() failed"), \ - PARA_ERROR(SET_BUFFER_TIME, "snd_pcm_hw_params_set_buffer_time_near() failed"), \ - PARA_ERROR(SET_RATE, "snd_pcm_hw_params_set_rate_near failed"), \ - PARA_ERROR(START_THRESHOLD, "snd_pcm_sw_params_set_start_threshold() failed"), \ - PARA_ERROR(STOP_THRESHOLD, "snd_pcm_sw_params_set_stop_threshold() failed"), \ - PARA_ERROR(ALSA_POLL_FDS, "could not get alsa poll fd"), \ + PARA_ERROR(ALSA, "alsa error"), \ #define WRITE_COMMON_ERRORS \