Zeroing few bytes flag - what way better?

Discussion created by Raistmer on Jul 28, 2010
Latest reply on Aug 10, 2010 by genaganna
via zeroing kernel or via buffer write?

I need to initialize float or float4 flag before kernel call.
What better to use, some memset kernel of one workitem or by writing float or float4 zero value from host to GPU memory?
In which case call overhead will be lower?