Better tperf defaults.
Better tperf defaults.

Summary: As in title. This increases tperf default perf from ~1100Mbps on my devserver to ~1700Mbps.

Reviewed By: jbeshay, afrind, kvtsoy

Differential Revision: D40814756

fbshipit-source-id: 6cd1fff87a1a6472d14b1250bd551f7f9a88f6ca

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