diff options
| author | Marcus Müller <mmueller@gnuradio.org> | 2021-06-20 18:54:36 +0200 |
|---|---|---|
| committer | mormj <34754695+mormj@users.noreply.github.com> | 2021-07-19 07:21:16 -0400 |
| commit | dd97527daadea86f7175c4c019dbeb96c2f47219 (patch) | |
| tree | b4753f2438c15fd75cb9dd3775cb9e6a10b96cb3 | |
| parent | 59af4f80dc9a1406ea7b4fde3b8d547a22c951ed (diff) | |
blocks: Throttle consume-only mode
When throttling a sample flow, it's not necessary to produce items at
the desired average rate - consuming them at a limited rate suffices to
slow down the processing of the whole flow graph just as well, and
avoids a copy.
Signed-off-by: Marcus Müller <mmueller@gnuradio.org>
| -rw-r--r-- | gr-blocks/include/gnuradio/blocks/throttle.h | 8 | ||||
| -rw-r--r-- | gr-blocks/lib/throttle_impl.cc | 10 | ||||
| -rw-r--r-- | gr-blocks/python/blocks/bindings/throttle_python.cc | 2 |
3 files changed, 16 insertions, 4 deletions
diff --git a/gr-blocks/include/gnuradio/blocks/throttle.h b/gr-blocks/include/gnuradio/blocks/throttle.h index 9372a8711b..b8a5151e17 100644 --- a/gr-blocks/include/gnuradio/blocks/throttle.h +++ b/gr-blocks/include/gnuradio/blocks/throttle.h @@ -1,6 +1,7 @@ /* -*- c++ -*- */ /* * Copyright 2005-2011,2013 Free Software Foundation, Inc. + * Copyright 2021 Marcus Müller * * This file is part of GNU Radio * @@ -30,6 +31,13 @@ namespace blocks { * precisely controlling the rate of samples. That should be * controlled by a source or sink tied to sample clock. E.g., a * USRP or audio card. + * + * You can insert this block "in series" with your sample flow, in which case it does a + * throttled copy of input to output. Alternatively, you can not connect its output and + * just connect this block's input in parallel to an existing block in your flow graph. In + * that case, Throttle will limit the rate at which samples are consumed; especially at + * higher rates, where the copying overhead might be significant, this is functionally not + * different to copying at a limited rate. */ class BLOCKS_API throttle : virtual public sync_block { diff --git a/gr-blocks/lib/throttle_impl.cc b/gr-blocks/lib/throttle_impl.cc index 199ddea588..201d7ce86f 100644 --- a/gr-blocks/lib/throttle_impl.cc +++ b/gr-blocks/lib/throttle_impl.cc @@ -32,7 +32,7 @@ throttle::sptr throttle::make(size_t itemsize, double samples_per_sec, bool igno throttle_impl::throttle_impl(size_t itemsize, double samples_per_second, bool ignore_tags) : sync_block("throttle", io_signature::make(1, 1, itemsize), - io_signature::make(1, 1, itemsize)), + io_signature::make(0, 1, itemsize)), d_itemsize(itemsize), d_ignore_tags(ignore_tags) { @@ -78,8 +78,12 @@ int throttle_impl::work(int noutput_items, // copy all samples output[i] <= input[i] const char* in = (const char*)input_items[0]; - char* out = (char*)output_items[0]; - std::memcpy(out, in, noutput_items * d_itemsize); + + // iff we have a connected output, then copy + if (!output_items.empty()) { + char* out = reinterpret_cast<char*>(output_items[0]); + std::memcpy(out, in, noutput_items * d_itemsize); + } d_total_samples += noutput_items; auto now = std::chrono::steady_clock::now(); diff --git a/gr-blocks/python/blocks/bindings/throttle_python.cc b/gr-blocks/python/blocks/bindings/throttle_python.cc index 88bf0ca443..3a67c3fc95 100644 --- a/gr-blocks/python/blocks/bindings/throttle_python.cc +++ b/gr-blocks/python/blocks/bindings/throttle_python.cc @@ -14,7 +14,7 @@ /* BINDTOOL_GEN_AUTOMATIC(0) */ /* BINDTOOL_USE_PYGCCXML(0) */ /* BINDTOOL_HEADER_FILE(throttle.h) */ -/* BINDTOOL_HEADER_FILE_HASH(e32468fa73eff1abd796a3fbf4dbb8e0) */ +/* BINDTOOL_HEADER_FILE_HASH(c3a597508d581cabdc653faaa323232c) */ /***********************************************************************************/ #include <pybind11/complex.h> |