add ability to limit concurrency (#565)

effective concurrency in zenserver can be limited via the `--corelimit=<N>` option on the command line. Any value passed in here will be used instead of the return value from `std::thread::hardware_concurrency()` if it is lower.

* added --corelimit option to zenserver
* made sure thread pools are configured lazily and not during global init
* added log output indicating effective and HW concurrency
* added change log entry
* removed debug logging from ZenEntryPoint::Run()

also removed main thread naming on Linux since it makes the output from `top` and similar tools confusing (it shows `main` instead of `zenserver`)

1 files changed, 2 insertions, 2 deletions

diff --git a/src/zenstore/blockstore.cpp b/src/zenstore/blockstore.cpp
index 0861baaf8..0fee18420 100644
--- a/src/zenstore/blockstore.cpp
+++ b/src/zenstore/blockstore.cpp
@@ -1688,7 +1688,7 @@ TEST_CASE("blockstore.iterate.chunks")
 												.Size		= DefaultIterateSmallChunkWindowSize * 2};
 	BlockStoreLocation BadBlockIndex		 = {.BlockIndex = 0xfffff, .Offset = 1024, .Size = 1024};
 
-	WorkerThreadPool WorkerPool(Max(std::thread::hardware_concurrency() - 1u, 4u));
+	WorkerThreadPool WorkerPool(Max(GetHardwareConcurrency() - 1u, 4u));
 
 	std::vector<BlockStoreLocation> Locations{FirstChunkLocation,
 											  SecondChunkLocation,
@@ -1807,7 +1807,7 @@ TEST_CASE("blockstore.thread.read.write")
 	std::vector<BlockStoreLocation> ChunkLocations;
 	ChunkLocations.resize(ChunkCount);
 
-	WorkerThreadPool WorkerPool(Max(std::thread::hardware_concurrency() - 1u, 8u));
+	WorkerThreadPool WorkerPool(Max(GetHardwareConcurrency() - 1u, 8u));
 	{
 		std::atomic<size_t> WorkCompleted = 0;
 		Latch				L(1);