We've observed that high CPU load for one user reading consoleText via Run#doConsoleText, which showed a bottleneck in decoding Base64:

at org.apache.commons.codec.binary.BaseNCodec.decode(BaseNCodec.java:387)
{{ at org.apache.commons.codec.binary.Base64.decodeBase64(Base64.java:697)}}
{{ at hudson.util.UnbufferedBase64InputStream.read(UnbufferedBase64InputStream.java:41)}}
{{ at hudson.util.UnbufferedBase64InputStream.read(UnbufferedBase64InputStream.java:53)}}
{{ at java.io.DataInputStream.read(Unknown Source)}}
{{ at java.io.DataInputStream.readFully(Unknown Source)}}
{{ at hudson.util.IOUtils.skip(IOUtils.java:87)}}
{{ at hudson.console.ConsoleNote.skip(ConsoleNote.java:286)}}
{{ at hudson.console.PlainTextConsoleOutputStream.eol(PlainTextConsoleOutputStream.java:68)}}
{{ at hudson.console.LineTransformationOutputStream.eol(LineTransformationOutputStream.java:60)}}
{{ at hudson.console.LineTransformationOutputStream.write(LineTransformationOutputStream.java:56)}}
{{ at hudson.console.LineTransformationOutputStream.write(LineTransformationOutputStream.java:74)}}
{{ at org.apache.commons.io.IOUtils.copyLarge(IOUtils.java:1793)}}
{{ at org.apache.commons.io.IOUtils.copyLarge(IOUtils.java:1769)}}
{{ at org.apache.commons.io.IOUtils.copy(IOUtils.java:1744)}}
{{ at hudson.model.Run.doConsoleText(Run.java:2090)}}

Looking at the implementation here, Java 8 provides a much much efficient Base64 decoder implementation, which has been benchmarked as 2x-3x as fast:

http://java-performance.info/base64-encoding-and-decoding-performance/

https://aws.amazon.com/blogs/developer/follow-up-on-base64-codec-performance/

JENKINS-43780 should cover most of the uses of the Trilead Base64 implementations