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Update the 5-stable roadmap. Remove items that are done or no londer

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relevant, add some new items, re-arrange the sections, and add a new
schedule.
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Scott Long 2003-09-14 19:41:40 +00:00
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@ -22,13 +22,14 @@
<!ENTITY t.releng.5 "<literal>RELENG_5</literal>">
<!ENTITY t.releng.5.1 "<literal>RELENG_5_1</literal>">
<!ENTITY t.releng.5.2 "<literal>RELENG_5_2</literal>">
<!ENTITY t.releng.5.3 "<literal>RELENG_5_3</literal>">
<!ENTITY t.releng.head "<literal>HEAD</literal>">
]>
<article>
<articleinfo>
<title>The Roadmap for 5-STABLE</title>
<title>The Road Map for 5-STABLE</title>
<authorgroup>
<corpauthor>The &os; Release Engineering Team</corpauthor>
@ -60,13 +61,12 @@
of 2003. Features like the GEOM block layer, Mandatory Access Controls,
ACPI, &sparc64; and ia64 platform support, and UFS snapshots, background
filesystem checks, and 64-bit inode sizes make it an exciting operating
system for both desktop and production users. However, some important
system for both desktop and enterprise users. However, some important
features are not complete. The foundations for fine-grained locking
and preemption in the kernel exist, but much more work is left to be
done. Work on Kernel Schedulable Entities (KSE), similar to Scheduler
Activations, has been ongoing but needs a push to realize its benefit.
Performance compared to &os; 4.<replaceable>X</replaceable> has
declined and must be restored and surpassed.</para>
done. Performance and stability compared to &os;
4.<replaceable>X</replaceable> has declined and must be restored and
surpassed.</para>
<para>This is somewhat similar to the situation that &os; faced in the
3.<replaceable>X</replaceable> series. Work on 3-CURRENT trudged along
@ -97,6 +97,15 @@
<sect1 id="major-issues">
<title>Major issues</title>
<para>The success of the 5.<replaceable>X</replaceable> series hinges on
the ability to deliver fine-graned threading and re-entrancy in the
kernel (also known as SMPng) and kernel-supported POSIX threads in
userland, while not sacrificing overall system stability or
performance.</para>
<sect2 id="SMPng">
<title>SMPng</title>
<para>The state of SMPng and kernel lockdown is the biggest concern for
5.<replaceable>X</replaceable>. To date, few major systems have come
out from under the kernel-wide mutex known as <quote>Giant</quote>.
@ -109,30 +118,35 @@
<itemizedlist>
<listitem>
<para>VM: the kmem_malloc(M_NOWAIT) path no longer needs Giant held.
The kmem_malloc(M_WAITOK) path is in progress and is expected to be
finished in the coming weeks. Other facets of the VM system, like
the VFS interface, buffer/cache, etc, are largely untouched.</para>
<para>VM: Kernel malloc is locked and free of Giant. The UMA zone
allocator is also free of Giant. vm_object locking is in progress
and is an important step to making the buffer/cache free of
Giant. Pmap locking remains to be started.</para>
</listitem>
<listitem>
<para>GEOM: The GEOM block layer was designed to run free of Giant,
but at this time no block drivers can run without Giant.
Additionally, it has the potential to suffer performance loss due
to its upcall/downcall data paths happening in kernel threads.
Lightweight context switches might help this.</para>
<para>GEOM: The GEOM block layer was designed to run free of Giant
and allow GEOM modules and underlying block drivers to run free
of Giant. Currently, only the &man.ata.4; and &man.aac.4; drivers
are locked and run without Giant. Work on other block drivers is
in progress. Locking the CAM subsystem is required for nearly all
SCSI drivers to run without Giant; this work has not started
yet.</para>
<para>Additionally, GEOM has the potential to suffer performance loss
due to its upcall and downcall data paths happening in kernel threads.
Improved lightweight context switches might help this.</para>
</listitem>
<listitem>
<para>Network: Locking of the TCP and UDP portions of the stack is
complete. Work is in progress to lock up the IP stack, including
the routing tree, ARP code, raw IP, and ifaddr and inet data
structures. IPv6 has been lightly touched during the inp locking
but is hindered by the KAME code being significantly out of date.
Work has not started on any of the other protocols such as
AppleTalk, XNS, or IPX. Locking of the socket layer is in progress
but has been largely untested. None of the hardware drivers or
Ethernet layers have been locked.</para>
<para>Network: Work has restarted on locking the network stack.
Routing tables, ARP, bridge, IPFW, Fast-Forward, TCP, UDP, IP,
Fast IPSEC, and interface layers are being targeted initially, along
with several Ethernet device drivers. The socket layer, IPv6, and
other protocol layers will be targeted later. The primary goal
of this work is to regain the performance found in
&os; 4.<replaceable>X</replaceable>. The cost of context switching
to the device driver ithreads and the netisr is still hampering
performance.</para>
</listitem>
<listitem>
@ -140,12 +154,12 @@
</listitem>
<listitem>
<para>buffer/cache: Initial work complete.</para>
<para>buffer/cache: Initial work complete on locking the buffer.</para>
</listitem>
<listitem>
<para>Proc: Work on locking the proc structure was ongoing for a
while but seems to have stalled.</para>
<para>Proc: Initial proc locking is in place, further progress is
expected for &os; 5.2.</para>
</listitem>
<listitem>
@ -159,8 +173,7 @@
</listitem>
<listitem>
<para>Pipes: complete with the exception of VM-related
optimizations.</para>
<para>Pipes: complete</para>
</listitem>
<listitem>
@ -181,12 +194,13 @@
</listitem>
<listitem>
<para>kernel encryption: crypto drivers and core &man.crypto.4; framework are
Giant-free. KAME IPsec and FAST IPSec have not been locked.</para>
<para>kernel encryption: crypto drivers and core &man.crypto.4;
framework are Giant-free. KAME IPsec has not been locked.</para>
</listitem>
<listitem>
<para>Sound subsystem: complete</para>
<para>Sound subsystem: complete, but lock order reversal problems seem
to persist.</para>
</listitem>
<listitem>
@ -199,158 +213,128 @@
</listitem>
</itemizedlist>
<para>Another issue with SMPng is interrupt latency. The overhead of
doing a complete context switch to a kernel interrupt thread is high
and shows noticeable latency. Work is ongoing to implement lazy
context switching on all platforms. Fine grained locking of drivers
will also help this, as will converting drivers to be as efficient as
possible in their interrupt routines.</para>
</sect2>
<para>Next, the state of KSE must resolved for &t.releng.5;. Work on it has
slowed noticeably in the past 6 months but appears to be picking up
again. There are a number of issues that must be addressed:</para>
<sect2 id="interrupts">
<title>Interrupt latency and servicing</title>
<para>SMPng introduced the concept of dedicating kernel threads, known as
ithreads, to servicing interrupts. With this, driver interrupt
service routines are allowed to block for mutexes, memory allocations,
etc. While this makes writing drivers easier, it introduces considerable
latency into the system due to the complete process context switch must
be performed in order to service the ithread. This is aggravated by the
extensive coverage over the kernel by the Giant mutex, and often results
in multiple sleeps and context switches in order to service an interrupt.
Drivers that register their interrupt as INTR_MPSAFE are less likely to
feel these aggravating effects, but the overhead of doing a context
switch remains. Interrupt service routines that are registered as
INTR_FAST are run directly from the interrupt context and do not suffer
these problems at all. However, the INTR_FAST property forces the
interrupt line to be exclusive; no sharing can occur on it. The
proliferation of shared interrupts on PC systems makes this
undesirable.</para>
<para>Several ideas have been proposed to help combat this problem:</para>
<itemizedlist>
<listitem>
<para>The userland threading library, currently called libkse, is
immature and has not been used for any significant threaded
application.</para>
<para>Special casing ithreads to be lightweight is a possibility. This
might involve reducing the amount of saved context for the ithread,
stack-borrowing from another kthread, and/or creating a new fast-path
to avoid the mi_switch() routine.</para>
</listitem>
<listitem>
<para>KSE has the potential to uncover latent race conditions and
create new ones. An audit needs to be performed to ensure that no
obvious problems exist.</para>
<para>A new interrupt model can be introduced to allow drivers to
register an 'interrupt filter' along with a normal service routine.
This would be similar to the Mac OSX model in use today. Interrupt
filter routines would allow the driver to determine if it is
interested in servicing the interrupt, allow it to squelch the
interrupt source, and possibly determine and schedule service
actions. It would run in the same context as the low-level interrupt
service routine, so sleeping would be strictly forbidden. If actions
that result in sleeping or blocking for long periods are required,
the filter would signal to the caller that its normal ithread routine
should be scheduled.</para>
</listitem>
</itemizedlist>
<para>According to the release schedule below, KSE kernel and userland
components must be functionality complete by June 2003 in order to be
included in the &t.releng.5; branch. For security and stability reasons,
if KSE cannot be finished in time then, by default, all KSE-specific
syscalls should be modified to return ENOSYS and all other KSE-specific
interfaces disabled. Deprecating KSE from &t.releng.5; but keeping it in
the &t.releng.head; branch will pose problems in porting bugfixes and features
between the two branches, so every effort should be made to finish it
on time.</para>
</sect2>
<sect2 id="KSE">
<title>Kernel-supported application threads</title>
<para>The FreeBSD 5.1 development cycle saw the KSE package jump into a
highly usable state. THR, an alternate threading package based on some
of the KSE kernel primitives but implementing purely 1:1 scheduling
semantics also appeared and is in a similarly experimental but usable
state. Users may interchange these two libraries along with the legacy
libc_r library via relinking their apps or by using the new libmap
feature of the runtime linker. This excellent progress must be driven
to completion before the &t.releng.5; branch point so that the libc_r
package can be deprecated.</para>
<itemizedlist>
<listitem>
<para>The kernel and userland components for KSE and THR must be
completed for all Tier-1 platforms. The decision on which thread
package to sanction as the default will likely be made on a
per-platform basis depending on the stability and completeness of
each package.</para>
</listitem>
<listitem>
<para>KSE must pass the ACE test suite on all Tier-1 platforms.
Additional real-world testing must also be performed to ensure
that the libraries are indeed useful. At a minimum, the following
packages should be tested:</para>
<itemizedlist>
<listitem><para>OpenOffice</para></listitem>
<listitem><para>KDE Desktop</para></listitem>
<listitem><para>Apache 2.x</para></listitem>
<listitem><para>BIND 9.2.x</para></listitem>
<listitem><para>MySQL</para></listitem>
<listitem><para>&java; 1.4.x</para></listitem>
</itemizedlist>
</listitem>
</itemizedlist>
</sect2>
</sect1>
<sect1 id="goals">
<title>Goals for 5-STABLE</title>
<title>Requirements for 5-STABLE</title>
<para>The goals for the &t.releng.5; branch point are:</para>
<para>The &t.releng.5 branch must offers users the same stability and
performance that is currently enjoyed in the &t.releng.4 branch.
While the goal of SMPng is to allow performance to far exceed what
is found in &t.releng.4; and its siblings BSD's, regaining performance
to the basic level is of the upmost importance. The branch must also
be mature enough to avoid ABI and API changes while still allowing
potential problems to be resolved.</para>
<itemizedlist>
<listitem>
<para>All subsystems and interfaces must be mature enough to be
maintainable for improvements and bug fixes.</para>
</listitem>
<listitem>
<para>Equal or better stability from &os; 4.8.</para>
</listitem>
<listitem>
<para>No functional regressions from 4.8. It is important to make
sure that users do not avoid upgrading to 5.x because of lost
functionality.</para>
</listitem>
<listitem>
<para>Performance on par with &os; 4.8 for most common operations.
Both UP and SMP configurations should be evaluated. SMP has the
potential to perform much better than
4.<replaceable>X</replaceable>, though for the purposes of creating
the &t.releng.5; branch, comparable performance between the two should
be acceptable.</para>
</listitem>
</itemizedlist>
<para>It is unrealistic to expect that the SMPng project will be fully
complete by &t.releng.5;, or that performance will be significantly better
than 4.<replaceable>X</replaceable>. However, focusing on a subset of
the outstanding tasks will give enough benefit for the branch to be
viable and maintainable. To break it down:</para>
<itemizedlist>
<listitem>
<para>ABI/API/Infrastructure stability - Enough infrastructure must
be in place and stable to allow fixes from &t.releng.head; to easily and
safely be merged into &t.releng.5;. Also, we must draw a line as to
what subsystems are to be locked down when we go into
5-STABLE.</para>
<sect2 id="API">
<title>ABI/API/Infrastructure stability</title>
<para>Enough infrastructure must be in place and stable to allow
fixes from &t.releng.head; to easily and safely be merged into
&t.releng.5;. Also, we must draw a line as to what subsystems are
to be locked down when we go into 5-STABLE.</para>
<itemizedlist>
<listitem>
<para>SMPng</para>
<itemizedlist>
<listitem>
<para>VM: Most codepaths, others than the ones that interact with
VFS, should be Giant-free for &t.releng.5;.</para>
</listitem>
<listitem>
<para>Network: Taking the network stack out from under Giant poses
the risk of uncovering latent bugs and races. Locking it down
but not removing Giant imposes further performance penalties. A
decision on which parts of the network stack should be locked and
taken out from under Giant for &t.releng.5; should be made no later
than March 15. Work on the IP, TCP, UDP,raw IP, routing sockets,
and &unix; domain sockets stands a good chance of being complete in
time for &t.releng.5;.</para>
<para>If the decision is made to not lift Giant from the stack,
then the locks in these layers could be optimized out with a
kernel config option. Having a Giant-free path from the the
hardware layer to the IP queues should be investigated as it
could allow significant performance gains in the network
benchmarks. If this can be achieved then the hardware interface
layer needs to allow for drivers to incrementally become free of
Giant. Locking down at least two Ethernet drivers would be
highly desirable. If the semantics are too complex to have the
stack free of Giant but not the hardware drivers, investigation
should be done into making it configurable.</para>
<para>Lesser-used network stacks like netatalk, netipx, etc, should
not break while this work is going on. However, locking them is
not a high priority. Special kernel config options might be
needed in order for these layers to operate with the rest of the
stack being locked and Giant free.</para>
</listitem>
<listitem>
<para>GEOM: At least 2 block drivers should be locked in order to
demonstrate that others can also be locked without changing the
interface to GEOM. The ATA driver is a good candidate for this,
though caution should be taken as it is also extremely
high-profile and any problems with it will affect nearly all
users of &os;.</para>
</listitem>
<listitem>
<para>Lazy context switching: sparc64 is the only platform that
performs lazy context switching when entering the kernel. The
performance gains promised by this are significant enough to
require that it be implemented for all other Tier-1
platforms.</para>
</listitem>
</itemizedlist>
</listitem>
<listitem>
<para>KSE: The kernel side of KSE must be functionally complete and
have undergone a security audit. libkse must be complete enough to
demonstrate a real-world application running correctly on it using
the standard &posix; Threads API. Examples would be apache 2.0,
&java;, and/or mozilla. A functional regression test suite is also a
requirement for &t.releng.5; and should test signal delivery,
scheduling, performance, and process security/credentials for both
KSE and non-KSE processes. KSE kernel and userland components must
also reach the same level of functionality for all Tier-1 platforms
<para>KSE: Both kernel and userland components must
reach the same level of functionality for all Tier-1 platforms
in both UP and SMP configurations. The definition of <quote>Tier-1
platforms</quote> can be found in
<ulink url="http://www.FreeBSD.org/doc/en_US.ISO8859-1/articles/committers-guide/archs.html"></ulink>.</para>
<ulink url="http://www.FreeBSD.org/doc/en_US.ISO8859-1/articles/committers-guide/archs.html"></ulink>. Continued testing against the ACE test
suite must be made as the &t.releng.5; branch draws near. KSE
must pose no functional regressions for the ongoing &java;
certification program. Common desktop and server applications
must run seamlessly under KSE. A policy must be decided on as
to which platforms will enable KSE as the default threading
package, how to allow the user to switch threading packages, and
how third-party packages will me made aware of these choices.</para>
</listitem>
<listitem>
@ -364,11 +348,9 @@
tracks the
progress of this and should be used to determine which drivers
must be converted for &t.releng.5; and which can be left behind.
Also, there has been talk by several developers and the original
author to give the busdma interface a minor overhaul. If this is
to happen, it needs to happen before &t.releng.5;. Otherwise,
differences between the old and new API will make driver
maintenance difficult.</para>
No new storage or network drivers shall be allowed into the
&os; source tree. Exceptions for other classes of drivers must
be justified in public discussion.</para>
</listitem>
<listitem>
@ -377,73 +359,57 @@
leaving this task solely to the OS. &os; must gain the ability to
manage and allocate PCI memory resources on its own. Implementing
this should take into account cardbus, PCI-HotPlug, and laptop
dockstation requirements. This feature will become increasingly
dock station requirements. This feature will become increasingly
critical through the lifetime of &t.releng.5;, and therefore is a
requirement for the &t.releng.5; branch.</para>
</listitem>
</itemizedlist>
</listitem>
</sect2>
<listitem>
<para>Performance: most performance gains hinge on the progress of
SMPng Areas that should be concentrated on are:</para>
<sect2 id="performance">
<title>Performance</title>
<para>Performance hinges on the progress of SMPng infrastructure and
the following areas:</para>
<itemizedlist>
<listitem>
<para>Storage I/O: I/O performance suffers from two problems, too
many expensive context switches, and too much work being done
in interrupt threads. Specifically, it takes 3 context
switches for most drivers to get from the hardware completion
interrupt to unblocking the user process: one for the
interrupt thread, one for the GEOM g_up thread, and one to get
back to the user thread. Drivers that attempt to be efficient
and quick in their interrupt handlers (as all should be)
usually also schedule a taskqueue, which adds a context switch
in between the interrupt thread and the g_up thread and brings
the total up to 4. Two things need to be done to attack
this:</para>
<itemizedlist>
<listitem>
<para>Make all drivers defer most of their processing out of
their interrupt thread. Significant performance gains have
been shown recently in the &man.aac.4; driver by making its
interrupt handler be <literal>INTR_MPSAFE</literal> and moving
all processing to a taskqueue.</para>
</listitem>
<listitem>
<para>investigate eliminating the taskqueue context switch by
adding a callback to the g_up thread that allows a driver to
do its interrupt processing there instead of in the
taskqueue.</para>
</listitem>
</itemizedlist>
<para>Storage: The GEOM block layer allows storage drivers to
run without Giant. All drivers that interface directly with
GEOM (as opposed to sitting underneath CAM or another middleware)
must be locked and free of Giant in both their strategy and
completion paths. Their interrupt handlers must also run free
of Giant.</para>
</listitem>
<listitem>
<para>Network: Network drivers suffer from the interrupt latency
previously mentioned as well as from the network stack being
partially locked down but not free from Giant. Possible
strategies for addressing this are described in the previous
section.</para>
<para>Network: The layers in the IPv4 path below the socket layer
must be locked and free of Giant. This includes the protocol,
routing, bridging, filtering, and hardware layers. Allowances must
be made for protocols that are not locked, especially IPv6.
Testing must also be performed to ensure stability, correctness,
and performance.</para>
</listitem>
<listitem>
<para>Other locking - XXX?</para>
<para>Interrupt and context switching: As discussed above, interrupt
latency and context switching have a severe impact of performance.
Context switching for ithreads and kthreads must be improved on
platforms. New interrupt handling models that allow for faster
more flexible handling of both traditional and MSI interrupts must
be investigated and implemented.</para>
</listitem>
</itemizedlist>
</listitem>
</sect2>
<listitem>
<para>Benchmarks and performance testing: Having a source of reliable
and useful benchmarks is essential to identifying performance
problems and guarding against performance regressions. A
<quote>performance team</quote> that is made up of people and
resources for formulating, developing, and executing benchmark
tests should be put into place soon. Comparisons should be made
against both &os; 4.<replaceable>X</replaceable> and Linux 2.4.x.
Tests to consider are:</para>
<sect2 id="benchmarks">
<title>Benchmarks and performance testing</title>
<para>Having a source of reliable and useful benchmarks is essential
to identifying performance problems and guarding against performance
regressions. A <quote>performance team</quote> that is made up of
people and resources for formulating, developing, and executing
benchmark tests should be put into place soon. Comparisons should
be made against both &os; 4.<replaceable>X</replaceable> and Linux
2.4/2.6. Tests to consider are:</para>
<itemizedlist>
<listitem>
@ -471,35 +437,16 @@
Note: does not compile with gcc 3.x yet.</para>
</listitem>
</itemizedlist>
</listitem>
</sect2>
<listitem>
<para>Features:</para>
<sect2 id="features">
<title>Features:</title>
<itemizedlist>
<listitem>
<para>ACPI: Intel's ACPI power management and device configuration
subsystem has become an integral part of &os;'s x86 and ia64
device configuration model. However, many bugs exist in Intel's
vendor code, our OS-specific code, and motherboard BIOSes, causing
many ACPI-enabled systems to fail to boot, misdetect drivers,
and/or have many other problems. Fixing these problems seems to
be an uphill battle and is often times causing a poor
first-impression of &os; 5.0. Most x86 systems can function with
ACPI disabled, and logic should be added to the boot loader and
sysinstall to allow users to easily and intuitively turn it off.
Turning off ACPI by default is prone to problems also as many
newer systems rely on it to provide correct interrupt routing
information. Also, a centralized resource should be created to
track ACPI problems and solutions. Linux uses the same Intel
vendor sources as &os;, so we should investigate how they have
handled some of the known problems.</para>
</listitem>
<listitem>
<para>NEWCARD/OLDCARD: The NEWCARD subsystem was made the default
for &os; 5.0. Unfortunately, it contains no support for
non-Cardbus bridges and falls victim to interrupt routine
non-Cardbus bridges and falls victim to interrupt routing
problems on some laptops. The classic 16-bit bridge support,
OLDCARD, still exists and can be compiled in, but this is highly
inconvenient for users of older laptops. If OLDCARD cannot be
@ -517,7 +464,7 @@
<listitem>
<para>New scheduler framework: The new scheduler framework is in
place, and users can select between the classic 44bsd scheduler
place, and users can select between the classic 44BSD scheduler
and the new ULE scheduler. A scheduler that demonstrates
processor affinity, HyperThreading and KSE awareness, and no
regressions in performance or interactivity characteristics must
@ -525,138 +472,66 @@
</listitem>
<listitem>
<para>sparc64 local console: neither syscons nor vt work on
sparc64, leaving it with only serial and <quote>fake</quote> OFW
console support. This is a major support hole for what is a
Tier-1 platform. Whether syscons can be shoe-horned in or
wscons be adopted from NetBSD is up for debate. However,
sparc64 must have local console support for &t.releng.5;. Having
this will also enable the XFree86 server to run, which is also a
requirement for &t.releng.5;.</para>
<para>GDB: GDB in the base system must work for sparc64, and
must also understand KSE thread semantics. GDB 5.3 is available
and is reported to address the sparc64 issues.</para>
</listitem>
</itemizedlist>
</sect2>
<sect2 id="documentation">
<title>Documentation:</title>
<itemizedlist>
<listitem>
<para>The manual pages, Handbook, and FAQ should be free from
content specific to &os; 4.<replaceable>X</replaceable>, i.e. all
text should be equally applicable to &os;
5.<replaceable>X</replaceable>. The installation section of the
handbook needs the most work in this area.</para>
</listitem>
<listitem>
<para>gcc/toolchain: gcc 3.3 might be available in time for
&t.releng.5; and might offer some attractive benefits, but also
likely to introduce ABI incompatibility with prior gcc versions.
ABI compatibility should be locked down for the &t.releng.5;
branch.</para>
<para>There has also been a request to move /usr/include/g++ to
/usr/include/g++-v3 to be more compliant with the stock behavior
of gcc. This should also be investigated for &t.releng.5;.</para>
</listitem>
<listitem>
<para>gdb: gdb from the base system should work for sparc64. It
should also understand KSE thread semantics, assuming that KSE
is included in the &t.releng.5; branch. gdb 5.3 is available and
there are reports that it should address the sparc64 issue.</para>
</listitem>
<listitem>
<para>&man.disklabel.8; regressions: The biggest casualty of the
introduction of GEOM appears to be the disklabel utility. The
<option>-r</option> option gives unpredictable results in most
cases now and should be removed or fixed. Work is planned for a
new unified interface for modifying labels and slices, however
this should not preclude disklabel from being fixed.</para>
<para>The release documentation needs to be complete and accurate
for all Tier-1 architectures. The hardware notes and
installation guides need specific attention.</para>
</listitem>
</itemizedlist>
</listitem>
<listitem>
<para>Documentation:</para>
<itemizedlist>
<listitem>
<para>The manual pages, Handbook, and FAQ should be free from
content specific to &os; 4.<replaceable>X</replaceable>, i.e. all
text should be equally applicable to &os;
5.<replaceable>X</replaceable>. The installation section of the
handbook needs the most work in this area.</para>
</listitem>
<listitem>
<para>The release documentation needs to be complete and accurate
for all Tier-1 architectures. The hardware notes and
installation guides need specific attention.</para>
</listitem>
<listitem>
<para>If &os; 5.1 is not the branch point for &t.releng.5; then the
Early Adopters Guide needs to be updated. This document should
then be removed just before the release closest to the &t.releng.5;
branch point.</para>
</listitem>
</itemizedlist>
</listitem>
</itemizedlist>
</sect2>
</sect1>
<sect1 id="schedule">
<title>Schedule</title>
<para>If branching &t.releng.5; at the 5.1 release is paramount, 5.1 will
probably need to move out by at least 3 months. The schedule would
be:</para>
<para>The original schedule of releasing &os; 5.2 and branching
&t.releng.5; in September 2003 is being pushed back due to the
complexity of the remaining tasks. The new schedule follows:</para>
<itemizedlist>
<listitem>
<para>Jun 30, 2003: KSE and SMPng feature freeze</para>
<para>Nov 5, 2003: 5.2-BETA, general code freeze</para>
</listitem>
<listitem>
<para>Aug 4, 2003: 5.1-BETA, general code freeze</para>
<para>Nov 19, 2003: 5.2-RC1, &t.releng.5.2; branched</para>
</listitem>
<listitem>
<para>Aug 18, 2003: 5.1-RC1, &t.releng.5; and &t.releng.5.1; branched</para>
<para>Nov 27, 2003: 5.2-RC2</para>
</listitem>
<listitem>
<para>Aug 25, 2003: 5.1-RC2</para>
<para>Dec 2, 2003: 5.2-RELEASE</para>
</listitem>
<listitem>
<para>Sept 1, 2003: 5.1-RELEASE</para>
</listitem>
</itemizedlist>
<para>Taking an incremental approach might be more beneficial. Releasing
5.1 in time for USENIX ATC 2003 will provide a wide audience for
productive feedback and will keep &os; visible. In this scenario, 5.1
should offer a significant improvement over 5.0 in terms of bug fixes
and performance. Lockdowns and improvements to the storage subsystem
and scheduler should be expected, the NEWCARD/OLDCARD issues should be
addressed, and all known bugs and regressions from the 5.0 errata list
should be fixed. KSE and other SMPng tasks that cannot finish in time
for 5.1 should also not reduce the stability of the release. The
schedule for this would be:</para>
<itemizedlist>
<listitem>
<para>May 5, 2003: 5.1-BETA, general code freeze</para>
<para>Mar 1, 2004: 5.3-BETA, general code freeze</para>
</listitem>
<listitem>
<para>May 19, 2003: 5.1-RC1, &t.releng.5.1; branched</para>
<para>Mar 15, 2004: 5.3-RC1, &t.releng.5; and &t.releng.5.3; branched</para>
</listitem>
<listitem>
<para>May 27, 2003: 5.1-RC2</para>
<para>Mar 22, 2004: 5.3-RC2</para>
</listitem>
<listitem>
<para>Jun 2, 2003: 5.1-RELEASE</para>
</listitem>
<listitem>
<para>Jun 30, 2003: KSE and SMPng feature freeze</para>
</listitem>
<listitem>
<para>Sept 1, 2003: 5.2-BETA, general code freeze</para>
</listitem>
<listitem>
<para>Sept 15, 2003: 5.2-RC1, &t.releng.5; and &t.releng.5.2; branched</para>
</listitem>
<listitem>
<para>Sept 22, 2003: 5.2-RC2</para>
</listitem>
<listitem>
<para>Sept 29, 2003: 5.2-RELEASE</para>
<para>Mar 29, 2004: 5.3-RELEASE</para>
</listitem>
</itemizedlist>
</sect1>