Allow custom sleep on tsc fallback.

This gives the user more control over the spectrum of precision vs. load time on Windows. Spall's output with much lower sleep times is still useful in my experience.

NOTE: A better API might be to allow the user to pass the freq as a param to "create_context" in case they already paid for it beforehand, but this seems fine for now.

core/prof/spall/spall.odin

@@ -67,14 +67,14 @@ Buffer :: struct {
 BUFFER_DEFAULT_SIZE :: 0x10_0000
 
 
-context_create :: proc(filename: string) -> (ctx: Context, ok: bool) #optional_ok {
+context_create :: proc(filename: string, freq_fallback_sleep := 2 * time.Second) -> (ctx: Context, ok: bool) #optional_ok {
 	fd, err := os.open(filename, os.O_WRONLY | os.O_APPEND | os.O_CREATE | os.O_TRUNC, 0o600)
 	if err != os.ERROR_NONE {
 		return
 	}
 	ctx.fd = fd
 
-	freq, freq_ok := time.tsc_frequency()
+	freq, freq_ok := time.tsc_frequency(freq_fallback_sleep)
 	ctx.precise_time = freq_ok
 	ctx.timestamp_scale = ((1 / f64(freq)) * 1_000_000) if freq_ok else 1
 

core/time/perf.odin

@@ -70,7 +70,7 @@ has_invariant_tsc :: proc "contextless" () -> bool {
 	return false
 }
 
-tsc_frequency :: proc "contextless" () -> (u64, bool) {
+tsc_frequency :: proc "contextless" (fallback_sleep := 2 * Second) -> (u64, bool) {
 	if !has_invariant_tsc() {
 		return 0, false
 	}
@@ -81,7 +81,7 @@ tsc_frequency :: proc "contextless" () -> (u64, bool) {
 		tsc_begin := intrinsics.read_cycle_counter()
 		tick_begin := tick_now()
 
-		sleep(2 * Second)
+		sleep(fallback_sleep)
 
 		tsc_end := intrinsics.read_cycle_counter()
 		tick_end := tick_now()