Spring boot log4j2 vs logback performance - spring-boot

Question

I'm seeing logback outperform log4j2 within a spring boot webapp. The logback and log4j2 webapps are incredibly simple. A single controller that logs a message at debug level. SLF4j is used as the facade. The logging configuration in both cases have only the root logger at error level. The test, run by jmeter, does an HTTP GET to the controller running the log statement a number of times. The results indicate that logback outperforms log4j2 by about 36%. Test results are consistent. Tests are run on aws c5.2xlarge instances.
I'm hoping someone can put this in their own test environment and validate the results. I would have thought this would be a fairly major issue for log4j2, but I haven't read anything about it. As far as I understand both webapps take a similar path to the logging implementation.
I'll share the main parts of the two spring boot webapps.
spring boot log4j2 webapp pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.4.5</version>
</parent>
<groupId>com.pryan</groupId>
<artifactId>spring-boot-log4j2</artifactId>
<version>0.0.1-SNAPSHOT</version>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-logging</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-log4j2</artifactId>
</dependency>
</dependencies>
<build>
<finalName>${project.artifactId}</finalName>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
Spring boot logback webapp pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.4.5</version>
</parent>
<groupId>com.pryan</groupId>
<artifactId>spring-boot-logback</artifactId>
<version>0.0.1-SNAPSHOT</version>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>
<build>
<finalName>${project.artifactId}</finalName>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
Main config class (same for both webapps)
package com.pryan.logging;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
#SpringBootApplication
public class AppConfig {
public static void main(String[] args) {
SpringApplication.run(AppConfig.class, args);
}
}
Controller (same for both webapps)
package com.pryan.logging;
import java.util.Date;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
#RestController
public class LogController {
private static final Logger logger = LoggerFactory.getLogger(LogController.class);
#RequestMapping(value="/debug", method = RequestMethod.GET)
public Date logging(#RequestParam(required=false, defaultValue="1") Integer numberOfLogMessages) {
for (int i=0; i<numberOfLogMessages; i++) {
logger.debug("Debug");
}
return new Date();
}
}
Log4j2.xml
<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="trace" name="SpringBootLog4j2" packages="">
<Appenders>
<RollingFile name="root" fileName="./logs/Log4j2.log" filePattern="./logs/$${date:yyyy-MM}/app-%d{MM-dd-yyyy}-%i.log.gz">
<PatternLayout>
<Pattern>%d{dd-MMM HH:mm:ss,SSS} [%5p] [%10.10t] [%50.50c] - %m%n</Pattern>
</PatternLayout>
<Policies>
<TimeBasedTriggeringPolicy />
<SizeBasedTriggeringPolicy size="250 MB" />
</Policies>
</RollingFile>
</Appenders>
<Loggers>
<Root level="error">
<AppenderRef ref="root" />
</Root>
</Loggers>
</Configuration>
logback.xml
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<appender name="FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
<file>./logs/Logback.log</file>
<rollingPolicy class="ch.qos.logback.core.rolling.FixedWindowRollingPolicy">
<fileNamePattern>./logs/Logback.log.%i</fileNamePattern>
<minIndex>1</minIndex>
<maxIndex>10</maxIndex>
</rollingPolicy>
<triggeringPolicy class="ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy">
<maxFileSize>10MB</maxFileSize>
</triggeringPolicy>
<encoder>
<pattern>%d{ISO8601} [%p{5}] [%t{10}] [%c{50}] - %m%n</pattern>
</encoder>
</appender>
<root level="ERROR">
<appender-ref ref="FILE" />
</root>
</configuration>