Why with @threads, the execution time is worse?

General Usage Performance
,
20

Thank you @stillyslalom for your explanation. I have compared between the @batch and the method here:https://discourse.julialang.org/t/optional-macro-invocation/18588/21

function ss()
dt = 0.001;     
tmin = 0;  
tmax = 5;
timeSim = tmin:dt:tmax;
A_Mat = spzeros(9,9); 
for i in 1:9
  A_Mat[i,i] = 1;
end
I_Mat = ones(9,3);
  iter = 0;
  for t in timeSim
      iter += 1;
      n=101
      #@threadsif n>100 for i in 1:n #by using it the time is  182 ms
      @batch minbatch=15 for i in 1:n   #by using it the time is  879.872 ms
      V_Mat = A_Mat \ I_Mat;
    end
end
end
using SparseArrays;
using LinearAlgebra;
using .Threads
using Polyester
using BenchmarkTools
@btime ss()

Any reason why @batch results in a really big number comparing with conditional thread @threadsif ?