Implement pre FFT tuning, which eliminates FFT offload latency from retuning delay.

.github/workflows/test.yaml

@@ -20,7 +20,7 @@ jobs:
         fetch-depth: 0
     - name: clang-format
       run: |
-        sudo apt-get update -yq && sudo apt-get install -yq clang-format python3-pip && pip3 install cmake_format && bin/run_c_format.sh $(pwd) lib include/gnuradio/iqtlabs
+        sudo apt-get update -yq && sudo apt-get install -yq clang-format python3-pip && pip3 install cmake_format && bin/run_c_format.sh $(pwd) lib include/gnuradio/iqtlabs grc
   test-latest:
     runs-on: ubuntu-latest
     steps:

.gitignore

@@ -5,5 +5,6 @@ libsigmf/
 flatbuffers/
 json/
 VkFFT/
+SPIRV-Tools/
 
 test_flow_graphs/test/

grc/CMakeLists.txt

@@ -3,11 +3,15 @@
 #
 
 install(
-  FILES iqtlabs_tuneable_test_source.block.yml iqtlabs_retune_fft.block.yml
-        iqtlabs_write_freq_samples.block.yml iqtlabs_image_inference.block.yml
+  FILES iqtlabs_tuneable_test_source.block.yml
+        iqtlabs_retune_fft.block.yml
+        iqtlabs_write_freq_samples.block.yml
+        iqtlabs_image_inference.block.yml
         iqtlabs_vector_to_json.block.yml
-    iqtlabs_vector_roll.block.yml
-    iqtlabs_vkfft_short.block.yml DESTINATION share/gnuradio/grc/blocks)
+        iqtlabs_vector_roll.block.yml
+        iqtlabs_retune_pre_fft.block.yml
+  DESTINATION share/gnuradio/grc/blocks)
 if(Vulkan_FOUND)
-  install(FILES iqtlabs_vkfft.block.yml DESTINATION share/gnuradio/grc/blocks)
+  install(FILES iqtlabs_vkfft.block.yml iqtlabs_vkfft_short.block.yml
+          DESTINATION share/gnuradio/grc/blocks)
 endif()

grc/iqtlabs_retune_fft.block.yml

@@ -13,12 +13,16 @@ documentation: |-
   input:
     vector of floats, representing FFT bucket values,
     tagged with center frequency.
+      cmd:
+        connection from retune_pre_fft to control tuning (optional).
   output:
     JSON scan summaries, one per line, containing "bucket" keys
     (with frequency: mean values), and "config" keys
     (representing block config).
-  tune:
-    connect to radio command port, generally "cmd".
+      tune:
+        connect to radio command port, generally "cmd".
+      json:
+        output buckets as zstd compressed JSON object (optional).
 
   parameters:
     tag: expected PMT tag containing center frequency
@@ -43,6 +47,7 @@ documentation: |-
                    "2.2e9-2.4e9,5.1e9-5.9e9".
     description: a string description to be included with each update.
     rotate_secs: if > 0, use a new epoch timestamped directory every N seconds.
+    pre_fft: if True, tuning is controlled by the retune_pre_fft block.
 
   example JSON output:
     { "ts": <epoch time>, "sweep start": <epoch time>,
@@ -59,7 +64,7 @@ templates:
     iqtlabs.retune_fft(${tag}, ${vlen}, ${nfft}, ${samp_rate}, ${freq_start},
     ${freq_end}, ${tune_step_hz}, ${tune_step_fft}, ${skip_tune_step_fft},
     ${fft_min}, ${fft_max}, ${sdir}, ${write_step_fft}, ${bucket_range},
-    ${tuning_ranges}, ${description}, ${rotate_secs})
+    ${tuning_ranges}, ${description}, ${rotate_secs}, ${pre_fft})
 
 cpp_templates:
   includes: ['#include <gnuradio/iqtlabs/retune_fft.h>']
@@ -68,7 +73,8 @@ cpp_templates:
     this->${id} = gr::iqtlabs::retune_fft::make(${tag}, ${vlen}, ${nfft},
     ${samp_rate}, ${freq_start}, ${freq_end}, ${tune_step_hz}, ${tune_step_fft},
     ${skip_tune_step_fft}, ${fft_min}, ${fft_max}, ${sdir}, ${write_step_fft},
-    ${bucket_range}, ${tuning_ranges}, ${description}, ${rotate_secs});
+    ${bucket_range}, ${tuning_ranges}, ${description}, ${rotate_secs},
+    ${pre_fft});
   link: ['libgnuradio-iqtlabs.so']
 
 asserts:
@@ -121,6 +127,8 @@ inputs:
     domain: stream
     dtype: float
     vlen: ${ vlen }
+  - label: cmd
+    domain: message
 
 outputs:
   - label: output
@@ -129,5 +137,8 @@ outputs:
     vlen: 1
   - label: tune
     domain: message
+  - label: json
+    domain: message
+
 
 file_format: 1

grc/iqtlabs_retune_pre_fft.block.yml

@@ -0,0 +1,62 @@
+---
+id: iqtlabs_retune_pre_fft
+label: retune_pre_fft
+category: '[iqtlabs]'
+flags: [python, cpp]
+
+templates:
+  imports: from gnuradio import iqtlabs
+  make: >
+    iqtlabs.retune_pre_fft(
+    ${nfft}, ${fft_batch_size},
+    ${tag}, ${freq_start}, ${freq_end},
+    ${tune_step_hz}, ${tune_step_fft}, ${skip_tune_step_fft},
+    ${tuning_ranges})
+
+cpp_templates:
+  includes: ['#include <gnuradio/iqtlabs/retune_pre_fft.h>']
+  declarations: 'gr::iqtlabs::retune_pre_fft::sptr ${id};'
+  make: >
+    this->${id} = gr::iqtlabs::retune_pre_fft::make(
+    ${nfft}, ${fft_batch_size},
+    ${tag}, {freq_start}, ${freq_end},
+    ${tune_step_hz}, ${tune_step_fft}, ${skip_tune_step_fft},
+    ${tuning_ranges});
+  link: ['libgnuradio-iqtlabs.so']
+
+parameters:
+  - id: nfft
+    dtype: int
+  - id: fft_batch_size
+    dtype: int
+  - id: tag
+    dtype: string
+    default: 'rx_freq'
+  - id: freq_start
+    dtype: raw
+  - id: freq_end
+    dtype: raw
+  - id: tune_step_hz
+    dtype: int
+  - id: tune_step_fft
+    dtype: int
+  - id: skip_tune_step_fft
+    dtype: int
+  - id: tuning_ranges
+    dtype: string
+
+inputs:
+  - label: input
+    domain: stream
+    dtype: complex
+    vlen: 1
+
+outputs:
+  - label: input
+    domain: stream
+    dtype: complex
+    vlen: ${ nfft * fft_batch_size }
+  - label: tune
+    domain: message
+
+file_format: 1

include/gnuradio/iqtlabs/CMakeLists.txt

@@ -12,6 +12,7 @@ install(
   FILES api.h
         tuneable_test_source.h
         retune_fft.h
+        retune_pre_fft.h
         write_freq_samples.h
         image_inference.h
         vector_to_json.h

include/gnuradio/iqtlabs/retune_fft.h

@@ -234,7 +234,8 @@ class IQTLABS_API retune_fft : virtual public gr::block {
                    uint64_t skip_tune_step_fft, double fft_min, double fft_max,
                    const std::string &sdir, uint64_t write_step_fft,
                    double bucket_range, const std::string &tuning_ranges,
-                   const std::string &description, uint64_t rotate_secs);
+                   const std::string &description, uint64_t rotate_secs,
+                   bool pre_fft);
 };
 
 } // namespace iqtlabs