From 5d018dc03549c1ee4958364712fb0c94e1bf2741 Mon Sep 17 00:00:00 2001
From: Lasse Collin <lasse.collin@tukaani.org>
Date: Sun, 9 Dec 2007 00:42:33 +0200
Subject: Imported to git.

---
 src/lzma/hardware.c | 99 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 99 insertions(+)
 create mode 100644 src/lzma/hardware.c

(limited to 'src/lzma/hardware.c')

diff --git a/src/lzma/hardware.c b/src/lzma/hardware.c
new file mode 100644
index 00000000..6cb3cdfc
--- /dev/null
+++ b/src/lzma/hardware.c
@@ -0,0 +1,99 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       hardware.c
+/// \brief      Detection of available hardware resources
+//
+//  Copyright (C) 2007 Lasse Collin
+//
+//  This program is free software; you can redistribute it and/or
+//  modify it under the terms of the GNU Lesser General Public
+//  License as published by the Free Software Foundation; either
+//  version 2.1 of the License, or (at your option) any later version.
+//
+//  This program is distributed in the hope that it will be useful,
+//  but WITHOUT ANY WARRANTY; without even the implied warranty of
+//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+//  Lesser General Public License for more details.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#include "private.h"
+#include "physmem.h"
+
+
+/// Maximum number of free *coder* threads. This can be set with
+/// the --threads=NUM command line option.
+size_t opt_threads = 1;
+
+
+/// Number of bytes of memory to use at maximum (only a rough limit).
+/// This can be set with the --memory=NUM command line option.
+/// If no better value can be determined, the default is 14 MiB, which
+/// should be quite safe even for older systems while still allowing
+/// reasonable compression ratio.
+size_t opt_memory = 14 * 1024 * 1024;
+
+
+/// Get the amount of physical memory, and set opt_memory to 1/3 of it.
+/// User can then override this with --memory command line option.
+static void
+hardware_memory(void)
+{
+	uint64_t mem = physmem();
+	if (mem != 0) {
+		mem /= 3;
+
+#if UINT64_MAX > SIZE_MAX
+		if (mem > SIZE_MAX)
+			mem = SIZE_MAX;
+#endif
+
+		opt_memory = mem;
+	}
+
+	return;
+}
+
+
+/// Get the number of CPU cores, and set opt_threads to default to that value.
+/// User can then override this with --threads command line option.
+static void
+hardware_cores(void)
+{
+#if defined(HAVE_NUM_PROCESSORS_SYSCONF)
+	const long cpus = sysconf(_SC_NPROCESSORS_ONLN);
+	if (cpus > 0)
+		opt_threads = (size_t)(cpus);
+
+#elif defined(HAVE_NUM_PROCESSORS_SYSCTL)
+	int name[2] = { CTL_HW, HW_NCPU };
+	int cpus;
+	size_t cpus_size = sizeof(cpus);
+	if (!sysctl(name, &cpus, &cpus_size, NULL, NULL)
+			&& cpus_size == sizeof(cpus) && cpus > 0)
+		opt_threads = (size_t)(cpus);
+#endif
+
+	// Limit opt_threads so that maximum number of threads doesn't exceed.
+
+#if defined(_SC_THREAD_THREADS_MAX)
+	const long threads_max = sysconf(_SC_THREAD_THREADS_MAX);
+	if (threads_max > 0 && (size_t)(threads_max) < opt_threads)
+		opt_threads = (size_t)(threads_max);
+
+#elif defined(PTHREAD_THREADS_MAX)
+	if (opt_threads > PTHREAD_THREADS_MAX)
+		opt_threads = PTHREAD_THREADS_MAX;
+#endif
+
+	return;
+}
+
+
+extern void
+hardware_init(void)
+{
+	hardware_memory();
+	hardware_cores();
+	return;
+}
-- 
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