Performance tips for a function which finds n maximums in a matrix

[rocco_sprmnt21]

using DataStructures

function Nlargest(v,N)
    maxn = heapify!(tuple.(v[1:N],1:N))
    maxn1=maxn[1]
    for i in N+1:length(v)
        e=(v[i],i)    
        if maxn1[1] < e[1]
            heappop!(maxn)
            heappush!(maxn,e)
            maxn1=maxn[1]
        end
    end
    #sort!(maxn,rev=true)
    maxn
end