Uncle Sam's 100,000 supervisors, executives and line managers are about to enter the produce-or-perish world of corporate-style management. If all goes as planned, federal bosses will soon be getting five-figure bonuses, or the boot, depending on how they and their subordinates perform.

The new system isn't off the drawing boards in most federal operations. But there is one spot where all federal bosses -- and employes who must work for and suffer or succeed with them -- can get a sneak preview of the brave new world. Would you believe the Small Business Administration?

SBA isn't a well-known federal operation. Or big one. But it has been involved in a crash program to develop one of the first flying models of President Carter's civil service reforms. SBA hopes to have a system of measurements, rewards and financial punishments in operation, and in some paychecks, in 60 to 90 days.

Federal departments that have been less bold, or are delayed by their greater size, are watching the SBA program. So are civil servants in the Grade 13 and above category who are considered managers, supervisors or executives. Those $29,000 to $50,000 people are all being put under a merit pay system. It will mean 20 percent bonuses for some, larger pay raises for some and bad report cards (leading to demotion or dismissal) for others.

SBA is far ahead of most federal agencies in implementing merit pay for supervisors, and setting up its executive rating system because it has pushed hard and because it is small enough -- in government terms -- to be manageable.

Nationwide SBA has about 6,000 employes. That is fewer than the Monday morning sick call in the Defense establishment, and fewer workers than the Veterans Administration has in training on any given day. SBA's executive corps totals only about 50. And it has only about 650 supervisors and managers whose October pay raises will be determined by the job they do. But the SBA does have something in common with all othe federal agencies -- a new system for rating supervisors and managers, for setting work goals, and for rewarding (or punishing) them regularly.

SBA plans to give out "significant and substantial" incentive awards early next year to outstanding members of its Senior Executive Service. The SES is made up of most top career and political officials in agencies. Most of them are at the $50,000 pay level.

SBA also plans, early in 1980, to be able to tell any of its marginal SES members they had better shape up or be prepared for demotion or dismissal.

Under the SBA system, which other federal agencies will adopt or modify for their own use, supervisors, managers and executives can:

Get "merit pay raises" each October substantially higher than their subordinates get.

Be held to 50 percent of the raise regular employes get if their work is not up to quality.

Win bonuses of up to 20 percent of salary if they are members of the Senior Executive Service.

Be demoted to Grade 15 if they don't measure up in the SES, or be fired if they do not have career civil service status.

Be eligible for one-time incentive awards of $1,000 or $2,0000 early this year in addition to regular pay raises.

All federal managers and supervisors -- in Grade 13 through 15 -- either have negotiated or soon will negotiate with their bosses to outline long-term (one year or more) objectives. Meeting, or failing to meet, those objectives will determine the amount of pay raises the bosses get. This will apply to virtually all supervisors and managers in government.

SBA officials estimate that about 15 percent of their supervisors and managers will rank in the top, and be eligible for higher-than-normal October pay raises. They speculate that an equal number of supervisors and managers may fall into the less-than-satisfactory category, meaning they would get only half of the percentage increase rank-and-file employes receive each Cotober.