I'm not sure how you set up your upstream and downstream project
For setting up downstream project, you provide the project names at Post-build Action -> Build Other Projects
For setting up upstream project, you provide the upstream project at Build Triggers -> Build after other projects are built
If you want to stream line the build, so that upstream is blocked or downstream is blocked when each other is building then use Advanced Project Option -> Block build when upstream/downstream project is building
Note that starting downstream first does not automatically start upstream, so if downstream depends on upstream always trigger only the upstream, downstream will be built automatically. If you set "Block build when upstream project is building" in downstream it won't start building until upstream is done.
BTW, for better control, you could use "lock and latch" plugin.
I have added one project as upstream project in the configuration of current job/project.
as per the wiki page of hudson, upstream projects are those which gets fired first whenever we fire the build for current project
but when i fire the build for current project, hudson does not start the build for upstream project
the current project/job is dependent on upstream project so i need upstream project to be built first than current project
but unfortunately it is not happening
[Hudson-Users] Re: [Hudson-Dev] upstream projects