Re: Test program: DU good Linux bad
Thierry Danis (danis@sagem.fr)
Fri, 7 May 1999 12:15:52 +0200
On Thu, May 06, 1999 at 09:50:10AM -0400, Jim Nance wrote:
> Hello All,
> I was playing around with an idea for avoiding the "thundering herd"
> problem on select/accept, and I think I found a similar problem on read().
> I thought it was worth posting about because neigher Digital Unix nor
> Solaris has this problem so that probably means its fixable.
> The program creates a pipe and forks off a number of children. Each of
> these children tries to read an int from the pipe, decrement it and write it
> back into the pipe. When the int goes to zero the program stops and prints
> its results. The times I get for 5000000 iterations are:
>
> Processes Linux(sec) Dig Unix(sec) Solaris(sec)
> 2 16.775 23.223 41.774
> 25 45.589 25.022 43.158
> 50 87.721 23.707 43.008
>
> Linux 2.2.7 333Mhz PII 500M ram
> Digital Unix 4.0D 600Mhz 21164 1.5G ram
> Solaris 5.6
>
Here, on an 'old' PC running FreeBSD-2.2.6 :
Running 5000000 inerations with 2 processes took 50.930 seconds
Running 5000000 inerations with 25 processes took 46.229 seconds
Running 5000000 inerations with 50 processes took 46.567 seconds
> --
> ----------------------------------------------------------------------------
> Jim Nance Avant! Corporation
> (919) 941-6655 Do you have sweet iced tea? jim_nance@avanticorp.com
> No, but there's sugar on the table.
--
Thierry Danis
Poste : 53 53 danis@spmo.sagem.fr
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