threads: elastically scale-up (#418)

* threads: elastically scale-up

* gh: bump code version

* threads: handle zero-sized requests and preload a la mpi

* omp: fix race conditions with elastic scaling

.env

@@ -1,4 +1,4 @@
-FAABRIC_VERSION=0.19.0
-FAABRIC_CLI_IMAGE=faasm.azurecr.io/faabric:0.19.0
+FAABRIC_VERSION=0.20.0
+FAABRIC_CLI_IMAGE=faasm.azurecr.io/faabric:0.20.0
 COMPOSE_PROJECT_NAME=faabric-dev
 CONAN_CACHE_MOUNT_SOURCE=./conan-cache/

.github/workflows/tests.yml

@@ -20,7 +20,7 @@ jobs:
     if: github.event.pull_request.draft == false
     runs-on: ubuntu-latest
     container:
-      image: faasm.azurecr.io/faabric:0.19.0
+      image: faasm.azurecr.io/faabric:0.20.0
     env:
       DEPLOYMENT_TYPE: gha-ci
     steps:
@@ -34,7 +34,7 @@ jobs:
     if: github.event.pull_request.draft == false
     runs-on: ubuntu-latest
     container:
-      image: faasm.azurecr.io/faabric:0.19.0
+      image: faasm.azurecr.io/faabric:0.20.0
     steps:
       - name: "Check out code"
         uses: actions/checkout@v4
@@ -45,7 +45,7 @@ jobs:
     if: github.event.pull_request.draft == false
     runs-on: ubuntu-latest
     container:
-      image: faasm.azurecr.io/faabric:0.19.0
+      image: faasm.azurecr.io/faabric:0.20.0
     steps:
       - name: "Check out code"
         uses: actions/checkout@v4
@@ -65,7 +65,7 @@ jobs:
       REDIS_QUEUE_HOST: redis
       REDIS_STATE_HOST: redis
     container:
-      image: faasm.azurecr.io/faabric:0.19.0
+      image: faasm.azurecr.io/faabric:0.20.0
       options: --privileged
     services:
       redis:
@@ -104,7 +104,7 @@ jobs:
       REDIS_QUEUE_HOST: redis
       REDIS_STATE_HOST: redis
     container:
-      image: faasm.azurecr.io/faabric:0.19.0
+      image: faasm.azurecr.io/faabric:0.20.0
       options: --privileged
     services:
       redis:
@@ -156,7 +156,7 @@ jobs:
       REDIS_QUEUE_HOST: redis
       REDIS_STATE_HOST: redis
     container:
-      image: faasm.azurecr.io/faabric:0.19.0
+      image: faasm.azurecr.io/faabric:0.20.0
     services:
       redis:
         image: redis

VERSION

@@ -1 +1 @@
-0.19.0
+0.20.0

src/batch-scheduler/BinPackScheduler.cpp

@@ -307,6 +307,13 @@ std::shared_ptr<SchedulingDecision> BinPackScheduler::makeSchedulingDecision(
     auto decisionType = getDecisionType(inFlightReqs, req);
     auto sortedHosts = getSortedHosts(hostMap, inFlightReqs, req, decisionType);
 
+    // For an OpenMP request with the single host hint, we only consider
+    // scheduling in one VM
+    bool isOmp = req->messages_size() > 0 && req->messages(0).isomp();
+    if (req->singlehosthint() && isOmp) {
+        sortedHosts.erase(sortedHosts.begin() + 1, sortedHosts.end());
+    }
+
     // Assign slots from the list (i.e. bin-pack)
     auto it = sortedHosts.begin();
     int numLeftToSchedule = req->messages_size();

src/batch-scheduler/SchedulingDecision.cpp

@@ -15,7 +15,7 @@ bool SchedulingDecision::isSingleHost() const
 
     std::string thisHost = conf.endpointHost;
     std::set<std::string> hostSet(hosts.begin(), hosts.end());
-    return hostSet.size() == 1;
+    return hostSet.size() <= 1;
 }
 
 void SchedulingDecision::addMessage(const std::string& host,