I think you will have to use the --wsesslog option to alter the distribution of session lengths. Martin On Mon, 3 Mar 2003, [GB2312] κѾѾ wrote: > Dear Sir/Madam, > > I know httperf has an parameter --wsess N1,N2,X. N2 is the mean session length. > Can httperf generate session whose length is exponentially distributed? >