Commit 989fd865 authored by Christian Borntraeger's avatar Christian Borntraeger Committed by Cornelia Huck
Browse files

s390/sclp: cache the sclp device 



With the current code a simple sclp command takes about 13000 ns
The biggest part seems to be the resolver of the object model. By
caching the sclp device the time for an sclp command goes down to
2500ns. Talking about real life scenarios, this change doubles
the speed of the sclp console when sending single bytes outputs
to /dev/console.

Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
parent 0c2a16a4

hw/s390x/sclp.c

+6 −1
Original line number Diff line number Diff line
@@ -26,7 +26,12 @@ 


static inline SCLPDevice *get_sclp_device(void)

{

    return SCLP(object_resolve_path_type("", TYPE_SCLP, NULL));

    static SCLPDevice *sclp;



    if (!sclp) {

        sclp = SCLP(object_resolve_path_type("", TYPE_SCLP, NULL));

    }

    return sclp;

}



/* Provide information about the configuration, CPUs and storage */