Remove CPU telemetry (background temperature/clock speed sampling)

The background thread that sampled CPU temperature and clock speed
during a run relied on undocumented, OS-specific interfaces: raw
AppleSMC keys on macOS, WMI ACPI thermal zones on Windows, and
/sys/class/thermal or /sys/class/hwmon on Linux. Testing on Apple
Silicon showed the SMC key scan can silently switch between different
physical sensors mid-run, producing discontinuous jumps in reported
temperature, and live per-core clock speed was never obtainable on
macOS through any public API. Disable the feature entirely rather
than ship unreliable data: drop the telemetry monitor thread, its
platform-specific sensor backends, and the telemetry field from
upload payloads. The pre-run background system-activity check
(--no-system-check) is unrelated and untouched.

Bump FB_VERSION to 0.4.2.

.github/workflows/release.yml

@@ -175,5 +175,5 @@ jobs:
             release/SHA256SUMS \
             --repo "$GITHUB_REPOSITORY" \
             --title "Release $RELEASE_TAG" \
-            --notes "Fixed x86/Linux builds on systems without OpenSSL development headers. Result uploads now use plain HTTP on every platform, removing the OpenSSL build and runtime dependency." \
+            --notes "Removed CPU telemetry (background temperature and clock speed sampling during benchmark runs). It relied on undocumented, OS-specific interfaces (raw AppleSMC keys on macOS, WMI ACPI thermal zones on Windows, /sys/class/thermal and /sys/class/hwmon on Linux) that proved unstable and inconsistent across operating systems and hardware, and live per-core clock speed was never obtainable on macOS at all through any public API. Rather than ship telemetry data that can silently jump between physical sensors mid-run or simply not exist on a given platform, this release disables the feature entirely: fossbench.net no longer accepts or displays it, and the client no longer collects it. The one-time background system-activity check (CPU/memory/process sampling before a run) is unaffected and still available via --no-system-check." \
             --generate-notes

src/app/benchmark.c

@@ -38,7 +38,7 @@
 #ifndef FB_API_BASE_URL
 #  define FB_API_BASE_URL "http://fossbench.net"
 #endif
-#define FB_VERSION "0.4.0"
+#define FB_VERSION "0.4.2"
 
 /*
  * Native Integer Math and Memory Bandwidth are the only two *measured*
@@ -167,7 +167,7 @@ extern uint64_t fb_c_chase(void **ptrs, uint64_t steps);
 #endif
 
 #ifndef MIN_SECONDS
-#  define MIN_SECONDS	2.0			/* Minimum run time. */
+#  define MIN_SECONDS	0.4			/* Minimum run time. */
 #endif
 #ifndef REPEATS
 #  define REPEATS	3			/* Number of tries. */

src/app/hw_detect.c

@@ -294,18 +294,31 @@ static int read_first_property(const char *path, char *dst, size_t cap)
  * by GetLogicalProcessorInformationEx describes exactly one physical core. */
 static long win_physical_cores(void)
 {
+	typedef BOOL (WINAPI *get_logical_processor_information_ex_fn)(
+		LOGICAL_PROCESSOR_RELATIONSHIP,
+		PSYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX, PDWORD);
+	get_logical_processor_information_ex_fn get_topology;
+	HMODULE kernel32;
 	DWORD length = 0;
 	BYTE *buffer, *p;
 	long cores = 0;
 
-	if (GetLogicalProcessorInformationEx(RelationProcessorCore, NULL, &length))
+	/* This API is unavailable on Windows XP. Resolve it dynamically so the
+	 * i386 compatibility build does not acquire a newer kernel32 import. */
+	kernel32 = GetModuleHandleA("kernel32.dll");
+	get_topology = kernel32 == NULL ? NULL :
+		(get_logical_processor_information_ex_fn)(uintptr_t)
+		GetProcAddress(kernel32, "GetLogicalProcessorInformationEx");
+	if (get_topology == NULL)
+		return 0;
+	if (get_topology(RelationProcessorCore, NULL, &length))
 		return 0;
 	if (GetLastError() != ERROR_INSUFFICIENT_BUFFER || length == 0)
 		return 0;
 	buffer = malloc(length);
 	if (buffer == NULL)
 		return 0;
-	if (GetLogicalProcessorInformationEx(RelationProcessorCore,
+	if (get_topology(RelationProcessorCore,
 			(PSYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX)buffer, &length)) {
 		for (p = buffer; p < buffer + length; ) {
 			PSYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX record =

src/app/upload.c

@@ -159,13 +159,13 @@ static int upload_results(const struct system_info *info,
 			  const struct result *real_single, uint64_t duration_ms,
 			  const struct background_metrics *background)
 {
-	char host[256], port[16], path[512], payload[32768];
+	char host[256], port[16], path[512], payload[131072];
 	char auth_header[600], response_body[2048], claim_url[1024], result_url[1024];
 	char cpu[512], model[512], os[512], compiler[256], kernel[256];
 	const char *base = FB_API_BASE_URL, *p, *slash, *colon;
 	int status = 0, payload_len;
 #if !defined(_WIN32)
-	char request[40000], response[4096];
+	char request[140000], response[4096];
 	struct addrinfo hints, *addresses = NULL, *a;
 	int fd = -1, request_len;
 #endif
@@ -224,7 +224,7 @@ static int upload_results(const struct system_info *info,
 		if (n < 0 || (size_t)n >= sizeof payload - used) return 0;
 		used += (size_t)n;
 		if (!append_result_tests(payload, sizeof payload, &used, real_multi, real_single)) return 0;
-		if (used + 3 >= sizeof payload) return 0;
+		if (used + 4 >= sizeof payload) return 0;
 		memcpy(payload + used, "]}}", 4);
 		payload_len = (int)(used + 3);
 	}