fix(llama.cpp): disable mirostat as default (mudler#2911)

Even if increasing the quality of the output, it has shown to have
performance drawbacks to be so noticeable that the confuses users about
speed of LocalAI ( see also
mudler#2780 ).

This changeset disables Mirostat by default (which can
be still enabled manually).

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Co-authored-by: Dave <dave@gray101.com>

Author: mudler

core/config/backend_config.go

@@ -287,7 +287,8 @@ func (cfg *BackendConfig) SetDefaults(opts ...ConfigLoaderOption) {
 	defaultTopP := 0.95
 	defaultTopK := 40
 	defaultTemp := 0.9
-	defaultMirostat := 2
+	// https://github.com/mudler/LocalAI/issues/2780
+	defaultMirostat := 0
 	defaultMirostatTAU := 5.0
 	defaultMirostatETA := 0.1
 	defaultTypicalP := 1.0