[ https://issues.jboss.org/browse/LOGMGR-120?page=com.atlassian.jira.plugin... ] David Lloyd commented on LOGMGR-120: ------------------------------------ The only reason we need the system property is because thread local access is very slow compared to our existing volatile int read. So this functionality would have to be enabled by a boolean constant field that we initialize from a system property so that C2 can eliminate the extra code completely when it isn't enabled, something like this: {code} final int effectiveLevel = loggerNode.getEffectiveLevel(); if ((level.intValue() < effectiveLevel || effectiveLevel == OFF_INT) && !(PER_THREAD_ENABLED && level.intValue() < threadLocal.get().intValue())) { return; } {code} If C2 compiles this code and PER_THREAD_ENABLED is false, it reduces like this: {code} if ((level.intValue() < effectiveLevel || effectiveLevel == OFF_INT) && !(PER_THREAD_ENABLED && level.intValue() < threadLocal.get().intValue())) { // becomes: if ((level.intValue() < effectiveLevel || effectiveLevel == OFF_INT) && !(false && level.intValue() < threadLocal.get().intValue())) { // becomes: if ((level.intValue() < effectiveLevel || effectiveLevel == OFF_INT) && !(false)) { // becomes: if ((level.intValue() < effectiveLevel || effectiveLevel == OFF_INT) && true) { // becomes: if (level.intValue() < effectiveLevel || effectiveLevel == OFF_INT) { // ...which is the original code == just as fast. {code} -- This message was sent by Atlassian JIRA (v6.3.11#6341)