这可能是由于采样率导致的问题。默认情况下，JMeter只会保存大约每秒钟一个采样。如果使用少量用户，则可能没有足够的数据点来创建有意义的图表。

要解决此问题，请在JMeter的jmeter.properties文件中更改以下行：

Increase this if you are getting OutOfMemoryErrors with large maps

#default.save.saveservice.max_saves_buffer=800

Increase this if the number of named objects exceeds the recursion_depth_limit

in saved beans.

#default.save.saveservice.name_depth_limit=100

Maximum size of elements in a collection that can be saved. Larger collections will be truncated

#default.save.saveservice.collection_limit=1000

Comment out the next line if you want to retain carriage returns in your CSV file

#default.save.saveservice.autopurge.enable=true

将default.save.saveservice.max_saves_buffer设置为更高的数字，例如2000或3000。这将允许JMeter保存更多的数据点，从而使图表更加精确。同时，还可以提高default.save.saveservice.autopurge.enable的值，以便在保存的时间段结束时保留更多的数据。

以下是更改实现的示例：

Increase this if you are getting OutOfMemoryErrors with large maps

default.save.saveservice.max_saves_buffer=3000

Increase this if the number of named objects exceeds the recursion_depth_limit

in saved beans.

default.save.saveservice.name_depth_limit=100

Maximum size of elements in a collection that can be saved. Larger collections will be truncated

default.save.saveservice.collection_limit=1000

Comment out the next line if you want to retain carriage returns in your CSV file

default.save.saveservice.autopurge.enable=true

保存更改并重新运行JMeter，如果采样率是问题所在，则应能够创建出精确的图表。