Grid 2 suites donot run parallel

I have SuiteA and SuiteB.
while iam using grid, suiteA first execute tests in parallel and then suiteB run tests in parallel.
But both suites A and B doesnot run in parallel.

[b:htgcm7a9][color=#FF0040:htgcm7a9]Suite_A.xml [/color:htgcm7a9][/b:htgcm7a9]
<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd">
<suite name="Suite A" verbose="3" parallel="tests" thread-count="2">

<test name="Test Profile">
<classes>
<class name="com.qtpselenium.framework.SuiteA.Profile" ></class>
</classes>
</test>

</suite>


[b:htgcm7a9][color=#FF0040:htgcm7a9]Suite_B.xml[/color:htgcm7a9][/b:htgcm7a9]
<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd">
<suite name="Suite B" verbose="3" parallel="tests" thread-count="2">

<test name="Test Add PortFolio NewStock">
<classes>
<class name="com.qtpselenium.framework.SuiteB.AddPortFolioNewStockTest" ></class>
</classes>
</test>

<test name="Test Modify Portfolio Stock">
<classes>
<class name="com.qtpselenium.framework.SuiteB.ModifyPortfolioStockTest" ></class>
</classes>
</test>



[b:htgcm7a9][color=#FF0000:htgcm7a9]testng.xml[/color:htgcm7a9][/b:htgcm7a9]
<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd">

<suite name="My suite" verbose="3" parallel="tests" thread-count="2">

<suite-files>
<suite-file path="./Suite_A.xml" />
<suite-file path="./Suite_B.xml" />

</suite-files>
</suite>


</suite>