system revision 1.9
1 $NetBSD: system,v 1.9 2012/01/15 02:49:12 agc Exp $ 2 3 NetBSD System Roadmap 4 ===================== 5 6 This is a small roadmap document, and deals with the main system 7 aspects of the operating system. 8 9 The following projects will appear in NetBSD 6.0: 10 1. 64-bit time values supported 11 2. Better Kernel Modules support 12 5. namei() tactical changes 13 9. namei() strategic changes 14 10. emap (ephemeral mapping) support for i386 and amd64 15 11. support for mDNSResponder 16 17 The following projects may make it into future releases: 18 3. Full kernel preemption for real-time threads 19 4. POSIX shared memory 20 6. Better resource controls 21 7. Improved observability: online crashdumps, remote debugging 22 8. Processor and cache topology aware scheduler 23 24 We'll continue to update this roadmap as features and dates get firmed up. 25 26 27 Some explanations 28 ================= 29 30 1. 64-bit time_t support 31 ------------------------- 32 33 The Unix 32-bit time_t value will overflow in 2037 - any mortgage calculations 34 which use a time_t value are in danger of overflowing at the present time - 35 and to address this, 64-bit time_t values will be used to contain the number 36 of seconds since 1970. This was completed in 5.99.7 by Christos (with no libc 37 major bump - kudos and respect), and will be in 6.0. 38 39 Responsible: christos 40 41 2. Better Kernel Module Support 42 ------------------------------- 43 44 Starting with 5.99.2, the kernel support for modules was enhanced by 45 ad, and GENERIC was switched over to be a MODULAR kernel. Support 46 from booting from modules, like ffs, was introduced at the same time. 47 Some work has been done by Luke Mewburn in this area to define module 48 locations and paths so that effective kernel development can be done 49 using modules. Kernel modules have been moved out of base.tgz and a new 50 modules.tgz has been created. 51 52 Responsible: ad, lukem 53 54 3. Full kernel preemption for real-time threads on non-x86 55 ---------------------------------------------------------- 56 57 With the revamp of the kernel concurrency model, much of the kernel is 58 fully multi-threaded and can therefore be preempted at any time. In 59 support of lower context switch and dispatch times for real-time 60 threads, full kernel preemption is being implemented. This has been 61 implemented already for i386 and x86_64 (and is in 5.0), but needs to 62 be extended to support the ARM, MIPS and SuperH ports. 63 64 Responsible: rmind 65 66 67 4. POSIX shared memory 68 ---------------------- 69 70 Implement POSIX shared memory facilities, which can be used to create the 71 shared memory objects and add the memory locations to the address space of 72 a process. 73 74 Responsible: rmind 75 76 77 5. Incremental namei improvements, Phase 1 78 ------------------------------------------ 79 80 In NetBSD 5.99.15, some changes were made to split the namei() routine 81 up into logical parts, so that changes can be made to the constituent 82 parts in a less intrusive way. This is in the repository now, and will 83 be in 6.0. 84 85 Responsible: dholland 86 87 88 6. Better resource controls 89 --------------------------- 90 91 A resource provisioning and control framework that extends beyond the 92 traditional Unix process limits. 93 94 Responsible: TBD 95 96 97 7. Improved observability: online crashdumps, remote debugging 98 -------------------------------------------------------------- 99 100 XXX crashdumps while the system is running 101 XXX firewire support in libkvm 102 103 Responsible: TBD 104 105 106 8. Processor and cache topology aware scheduler 107 ----------------------------------------------- 108 109 Implement the detection of the topology of the processors and caches. 110 Improve the scheduler to make decisions about thread migration 111 according to the topology, to get better thread affinity and less 112 cache thrashing, and thus improve overall performance in modern SMP 113 systems. 114 115 Responsible: rmind 116 117 118 9. Incremental namei improvements, Phase 2 119 ------------------------------------------ 120 121 Building on the namei() split which was introduced in 5.99.15 (see (5) 122 above), further changes will be introduced: see the changes to namei 123 outlined in Message-ID: <20080319053709.GB3951 (a] netbsd.org> for more 124 information. This will simplify the locking and behavior of namei() 125 calls within the kernel to resolve path names within file systems. 126 127 Responsible: dholland 128 129 130 10. Ephemeral Mapping 131 --------------------- 132 133 Responsible: rmind 134 135 136 11. Multicast DNS and DNS Service Discovery 137 ------------------------------------------- 138 139 mDNSResponder (also known as mdnsd on some systems) is a daemon invoked 140 at boot time to implement Multicast DNS and DNS Service Discovery. On Mac 141 OS X 10.6 (Snow Leopard), mDNSResponder is also the system-wide Unicast 142 DNS Resolver. Ty Sarna added support for mdnsd to NetBSD-current, and it 143 will appear in NetBSD 6.0. 144 145 146 Alistair Crooks 147 Sat Jan 14 11:40:49 PST 2012 148
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