android_system_core/logd

The properties that logd and friends react to are:

name                       type default  description
ro.logd.auditd             bool   true   Enable selinux audit daemon
ro.logd.auditd.dmesg       bool   true   selinux audit messages sent to dmesg.
ro.logd.auditd.main        bool   true   selinux audit messages sent to main.
ro.logd.auditd.events      bool   true   selinux audit messages sent to events.
persist.logd.security      bool   false  Enable security buffer.
ro.organization_owned      bool   false  Override persist.logd.security to false
ro.logd.kernel             bool+ svelte+ Enable klogd daemon
ro.logd.statistics         bool+ svelte+ Enable logcat -S statistics.
ro.debuggable              number        if not "1", logd.statistics &
                                         ro.logd.kernel default false.
logd.logpersistd.enable    bool   auto   Safe to start logpersist daemon service
logd.logpersistd          string persist Enable logpersist daemon, "logcatd"
                                         turns on logcat -f in logd context.
					 Responds to logcatd, clear and stop.
logd.logpersistd.buffer          persist logpersistd buffers to collect
logd.logpersistd.size            persist logpersistd size in MB
logd.logpersistd.rotate_kbytes   	 persist logpersistd outout file size in KB.
persist.logd.logpersistd   string        Enable logpersist daemon, "logcatd"
                                         turns on logcat -f in logd context.
persist.logd.logpersistd.buffer    all   logpersistd buffers to collect
persist.logd.logpersistd.size      256   logpersistd size in MB
persist.logd.logpersistd.count     256   sets max number of rotated logs to <count>.
persist.logd.logpersistd.rotate_kbytes   1024  logpersistd output file size in KB
persist.logd.size          number  ro    Global default size of the buffer for
                                         all log ids at initial startup, at
                                         runtime use: logcat -b all -G <value>
ro.logd.size               number svelte default for persist.logd.size. Larger
                                         platform default sizes than 256KB are
                                         known to not scale well under log spam
                                         pressure. Address the spam first,
                                         resist increasing the log buffer.
persist.logd.size.<buffer> number  ro    Size of the buffer for <buffer> log
ro.logd.size.<buffer>      number svelte default for persist.logd.size.<buffer>
ro.config.low_ram          bool   false  if true, logd.statistics,
                                         ro.logd.kernel default false,
                                         logd.size 64K instead of 256K.
persist.logd.filter        string        Pruning filter to optimize content.
                                         At runtime use: logcat -P "<string>"
ro.logd.filter       string "~! ~1000/!" default for persist.logd.filter.
                                         This default means to prune the
                                         oldest entries of chattiest UID, and
                                         the chattiest PID of system
                                         (1000, or AID_SYSTEM).
log.tag                   string persist The global logging level, VERBOSE,
                                         DEBUG, INFO, WARN, ERROR, ASSERT or
                                         SILENT. Only the first character is
                                         the key character.
persist.log.tag            string build  default for log.tag
log.tag.<tag>             string persist The <tag> specific logging level.
persist.log.tag.<tag>      string build  default for log.tag.<tag>

NB:
- auto - managed by /init
- bool+ - "true", "false" and comma separated list of "eng" (forced false if
  ro.debuggable is not "1") or "svelte" (forced false if ro.config.low_ram is
  true).
- svelte - see ro.config.low_ram for details.
- svelte+ - see ro.config.low_ram and ro.debuggable for details.
- ro - <base property> temporary override, ro.<base property> platform default.
- persist - <base property> override, persist.<base property> platform default.
- build - VERBOSE for native, DEBUG for jvm isLoggable, or developer option.
- number - support multipliers (K or M) for convenience. Range is limited
  to between 64K and 256M for log buffer sizes. Individual log buffer ids
  such as main, system, ... override global default.
- Pruning filter rules are specified as UID, UID/PID or /PID. A '~' prefix indicates that elements
  matching the rule should be pruned with higher priority otherwise they're pruned with lower
  priority. All other pruning activity is oldest first. Special case ~! represents an automatic
  pruning for the noisiest UID as determined by the current statistics.  Special case ~1000/!
  represents pruning of the worst PID within AID_SYSTEM when AID_SYSTEM is the noisiest UID.