From 64916077c34b6f8a40ed91c868e9bd81f2e11de1 Mon Sep 17 00:00:00 2001
From: Florian Schmaus <flow@cs.fau.de>
Date: Wed, 9 Feb 2022 16:41:40 +0100
Subject: [PATCH] [Context] Make context size and assumed page size
configurable
Also keep the context size at 64 KiB (there was a comment that
errorneously indicated that the context size is 4 MiB).
---
emper/Context.hpp | 6 +++++-
emper/Emper.hpp | 5 +++++
emper/lib/math.hpp | 4 ++++
meson.build | 2 ++
meson_options.txt | 14 ++++++++++++++
5 files changed, 30 insertions(+), 1 deletion(-)
diff --git a/emper/Context.hpp b/emper/Context.hpp
index fee4f8bb..49f5c287 100644
--- a/emper/Context.hpp
+++ b/emper/Context.hpp
@@ -13,12 +13,15 @@
#include "Common.hpp" // for func_t, DIE, ALIGN_TO_CACHE_LINE
#include "Debug.hpp" // for LOGD, LogSubsystem, LogSubsystem::C, Logger
#include "Emper.hpp" // for Emper::DEBUG
+#include "lib/math.hpp"
class AbstractFiber;
class ContextManager;
class Dispatcher;
class Fibril;
+namespace em = emper::lib::math;
+
extern "C" [[noreturn]] void switch_and_load_context(void** toTos);
// *Not* marked as 'noreturn' because save_and_switch_context does
// *actually return at some point, unlike the other switch_*
@@ -28,7 +31,8 @@ extern "C" [[noreturn]] void switch_context(void** toTos);
class ALIGN_TO_CACHE_LINE Context : Logger<LogSubsystem::C> {
private:
- static const unsigned int CONTEXT_SIZE = 0xffff; // 1024 * 1024 * 4;
+ static constexpr size_t CONTEXT_SIZE =
+ em::roundUp(emper::MIN_CONTEXT_STACK_SIZE, emper::ASSUME_PAGE_SIZE);
static thread_local Context* currentContext;
diff --git a/emper/Emper.hpp b/emper/Emper.hpp
index 488b9bf8..1e805285 100644
--- a/emper/Emper.hpp
+++ b/emper/Emper.hpp
@@ -278,4 +278,9 @@ static const bool CONTEXT_MANAGER_WITH_MEMORY_MANAGER =
false
#endif
;
+
+static const size_t ASSUME_PAGE_SIZE = EMPER_ASSUME_PAGE_SIZE;
+
+static const size_t MIN_CONTEXT_STACK_SIZE = EMPER_MIN_CONTEXT_STACK_SIZE;
+
} // namespace emper
diff --git a/emper/lib/math.hpp b/emper/lib/math.hpp
index 953d7445..a2e8e95b 100644
--- a/emper/lib/math.hpp
+++ b/emper/lib/math.hpp
@@ -65,4 +65,8 @@ class RunningAverage {
}
};
+constexpr size_t roundUp(size_t number, size_t multiple) {
+ size_t multiple_count = (number + multiple - 1) / multiple;
+ return multiple_count * multiple;
+}
} // namespace emper::lib::math
diff --git a/meson.build b/meson.build
index 91d72dd8..5b3a16e7 100644
--- a/meson.build
+++ b/meson.build
@@ -70,6 +70,8 @@ conf_data.set('EMPER_CONTINUATION_STEALING_MODE', continuation_stealing_mode)
conf_data.set('EMPER_CONTINUATION_STEALING_MADVISE_STACK', get_option('continuation_stealing_madvise_stack'))
conf_data.set('EMPER_BUILD_WITH_CLANG', cpp_is_clang)
conf_data.set('EMPER_CONTEXT_MANAGER_WITH_MEMORY_MANAGER', get_option('context_manager_with_memory_manager'))
+conf_data.set('EMPER_ASSUME_PAGE_SIZE', get_option('assume_page_size'))
+conf_data.set('EMPER_MIN_CONTEXT_STACK_SIZE', get_option('min_context_stack_size'))
if continuation_stealing_mode == 'locked' and not locked_ws_queue
error('*Locked* continuation stealing only works with locked work-stealing queues (locked_ws_queue=true)')
diff --git a/meson_options.txt b/meson_options.txt
index 0f7cabd9..cdf68da0 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -237,3 +237,17 @@ option(
description: 'Use the memory manager in context manager for better context caching. This may increases the memory footprint',
value: true
)
+option(
+ 'assume_page_size',
+ type: 'integer',
+ description: 'Assume the given page size in bytes',
+ value: 4096,
+ min: 1,
+)
+option(
+ 'min_context_stack_size',
+ type: 'integer',
+ description: 'Set the size in bytes of stacks used by an execution context (will potentially be rounded up to the next page size)',
+ value: 65536,
+ min: 1,
+)
--
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