====== lsof port ======
**DONE**
Build kernel hooks so that the lsof port doesn't need to grovel in kvm and isn't tied to a specific kernel build.

====== Serial console and polled I/O ======

When using a serial console, kernel printfs end up calling into a polled I/O path, potentially stalling kernel operations until the output is finished being transmitted.  This is a particular problem at 9600 baud.
(Examples of kernel printfs include link state messages, aac(4) COMMAND TIMEOUT messages, etc.)
Polled I/O is probably still needed for the debugger, panic handling, etc.

Printf() ends up invoking cnputc(), which calls siocnputc() in the default 6.x serial console case and uart_cnputc() in the default 8.x serial console case.  These functions spin while waiting for the tx register to be ready.

(reqst00227383)

  * Apparently jhb@ has been discussing approaches here
  * Attilio has done related work in the past, related to messages output during boot

<code>
printf
tprintf
uprintf
log

sysctl kern.consmsgbuf_size
sysctl kern.msgbuf
sysctl kern.msgbuf_clear
sysctl security.bsd.unprivileged_read_msgbuf

/dev/klog
</code>

  * http://svn.freebsd.org/viewvc/base/head/sys/kern/subr_prf.c
  * http://svn.freebsd.org/viewvc/base/head/sys/kern/subr_log.c

====== Debugging ======

===== Kernel core enhancements =====

Be able to extract the following from a core:
  * hostname
  * hash (sha-1 etc.) of kern.bootfile to positively identify the kernel binary that was running
  * uptime
  * current time of day

//reqst00277326 [debug] Include kernel ident data at panic time//
//reqst00193848 Add softclock backlog text to sw watchdog panic to aid in debugging//

===== Serial debugger use with conserver =====

A remote serial debugging session can be initiated by using "kgdb -r" if a local serial port is available and connected to the device under test.  Extend this to communicate with a device under test connected via the [[http://www.freshports.org/comms/conserver-com/|Conserver]] port.

===== Memory search =====

Add a command to gdb or lldb to allow searching memory for a value or byte string.  Now implemented in lldb [[http://llvm.org/viewvc/llvm-project?view=revision&revision=186127|r186127]].

===== Valgrind =====

===== USB kernel debugging =====

Use a [[http://www.coreboot.org/EHCI_Debug_Port|EHCI Debug Port]] for ddb or gdb.  Design for an adapter can be found at https://bitbucket.org/kmalkki/fx2lib .

====== Jail enhancements ======

===== Per-jail release overrides =====

Allow release-related variables to be set on a jail-wide basis.

  * uname
  * kern.osreldate (see [[https://reviews.freebsd.org/D1948]])

  * bz and kib interested
  * Should be relatively easy to implement in the 9.1+ jail infrastructure

===== Filesystem support =====

Add support for mounting in jails:
  * devfs (Possible in 9.1+ via allow.mount.devfs)
  * nullfs (Possible in 9.1+ via allow.mount.nullfs)
  * unionfs

====== Comprehensive time accounting ======

Completely avoid statclock vs hardclock aliasing and other issues by switching from sampled CPU time accounting to comprehensive (i.e., by recording a CPU counter on each context switch).

  * phk
  * jhb

====== Installation packaging and deployment ======