The Design and Implementation of the Anykernel and Rump Kernels

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218 version swap no swap NetBSD 5.1 17MB 20MB NetBSD 5.99.48 18MB 24MB Table 4.3: Minimum memory required to boot the standard installation. The memory represents the amount required by the guest. The amount of host memory consumed may be higher due to virtualization overhead. 1600 1400 memory usage (kB) 1200 1000 800 600 400 200 0 kern tcp/ip tmpfs audio Figure 4.10: Memory usage of rump kernels per idle instance. The figures represent the amounts of memory used on the host. 4.6 Performance Last, we look at performance figures for rump kernels. Examples of the metrics include syscall overhead, memory footprint and bootstrap time. We compare results against other virtualization technologies and against the native system. Even though the anykernel makes it possible to run the same drivers in the monolithic kernel as well as rump kernels, the performance of a rump kernel needs to be on a level where it does not hinder the execution of the intended use cases. Furthermore, we are interested in seeing if rump kernels can outperform other virtualization technologies.
219 4.6.1 Memory Overhead We define memory overhead as the amount of memory required by the virtualized OS. We analyze the amount of memory required to successfully boot a standard NetBSD installation up to the root shell prompt in less than 5 minutes. The results are presented in Table 4.3. They were obtained by running anita install on the release build and testing if the system boots with different values for qemu -m, where the -m parameter controls the amount of hardware memory presented to the guest. A big difference between 5.1 and 5.99.48 is that the latter uses a partially modular kernel by default. Modularity means that all drivers are not loaded at bootstrap, but rather on-demand as they are required. On-demand loading in turn means that the memory requirement of the default installation of 5.99.48 is closer to what is actually required by an application, since fewer unnecessary drivers are loaded into unpageable kernel memory. However, it is not surprising that 5.99.48 requires more memory due to the tendency of software to grow in size. Still, the default installation may not represent the true minimum required by an application. If we estimate that the memory consumption of NetBSD can be brought down to 1/4th by rigorous source level customization, the true minimum memory required to boot the full OS version of NetBSD 5.99.48 is 4.5MB. Next, we present the host memory consumption for various rump kernel instances in Figure 4.10. Again, we measure the second instance for reasons listed above. In the figure, the kern configuration contains nothing but the rump kernel base. The net configuration contains TCP/IP drivers. The tmpfs configuration supports mounting a tmpfs file system, and the audio configuration provides the NetBSD pseudo-audio driver (pad ). Notably, the audio configuration also includes the vfs faction, since audio devices are accessed via /dev/audio.
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Department of Computer Science and
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9 Preface Meet the new boss Same as
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11 Then there is my dear Xi, who, s
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14 2.3.3 InterruptsandPreemption...
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16 4.1.1 Implementation Effort ....
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18 Appendix C Patches to the 5.99.4
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20 ISA LGPL LRU LWP MD MI MMU NIC O
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23 List of Figures 2.1 Rumpkernelhi
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25 4.14 Time to execute 5M system c
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29 1 Introduction In its classic ro
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31 and application-level drivers. T
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33 We define an anykernel to be an
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35 Our implementation supports rump
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37 The project was done in small in
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39 2 The Anykernel and Rump Kernels
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41 building on top of the entities
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43 Drivers in a rump kernel remain
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45 Figure 2.1: Rump k
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47 in Section 3.2.3. Whenever discu
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49 int rumpns_bpfopen(dev_t, int, i
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51 Figure 2.4:
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53 while the application logic stil
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55 We must solve the lack of a rump
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57 2.3.1 Kernel threads Up until no
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59 void * pool_cache_get_paddr(pool
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61 2.3.4 An Example We present an e
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63 Figure 2.6: Prov
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65 The straightforward use of exist
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68 We identified three obstacles fo
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70 for loadable kernel modules (dis
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72 e.g. the routine for mapping a p
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74 3.2.1 C Symbol Namespaces In the
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76 the double underscore namespace
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78 since the representation might n
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80 The following rumpuser interface
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82 The entry point rump_schedule()
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84 3.3.1 CPU Scheduling Recall from
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86 The fastpath is taken in cases w
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88 Releasing a CPU requires the fol
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90 10 8 seconds 6 4 2 0 1CPU 2CPU n
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92 Hardware interrupt handlers are
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94 Due to the design choice that a
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96 in. Therefore, we should critica
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98 Pager window create+access time
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100 A rump kernel can be configured
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102 Since all pages managed by the
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104 not in control of thread schedu
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106 synchronization part of the alg
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108 /* * Run a cross call to cycle
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110 kernel needs to do is make sure
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112 The kernel with uniprocessor lo
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114 the header file while open() c
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116 The same wrapper works both for
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118 5. Some calling conventions (e.
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120 int rump_pub_lwproc_rfork(int a
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122 By convention, file system devi
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124 ule directory tree from /stand
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126 After these steps have been per
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128 Host Dynamic Linker Using the h
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130 for (i = 0; i < SYS_NSYSENT; i+
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132 into a rump kernel and the driv
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134 sys/arch/x86/include/cpu.h: #de
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136 3.8.4 Rump Component Init Routi
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138 RUMP_COMPONENT(RUMP_COMPONENT_N
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140 We have three distinct cases we
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142 # ifconfig tap0 create # ifconf
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144 Unprivileged use of host’s ne
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146 DOMAIN_DEFINE(sockindomain); co
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148 issue another write before the
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150 using an interface called USBDI
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152 The kernel device configuration
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154 # $NetBSD: UMASS.ioconf,v 1.4 2
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156 USB Host Controller Hub0 (root)
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158 Figure 3.30: File s
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160 in-kernel mount: /dev/sd0e /m/u
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162 structure being created by rump
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164 3.12.1 Client-Kernel Locators B
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166 A tmpfs server listening on INA
Page 170 and 171: 168 Request Arguments Response Desc
Page 172 and 173: 170 Host syscall rump syscall 1. op
Page 174 and 175: 172 A client’s initial connection
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Page 178 and 179: 176 stdin/stdout, the new file desc
Page 180 and 181: 178 Supporting fork() Recall, the f
Page 182 and 183: 180 As with fork, most of the kerne
Page 184 and 185: 182 Anecdotal analysis For several
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Page 188 and 189: 186 SLOC 8000 7000 6000 5000 4000 3
Page 190 and 191: 188 Total commits to the kernel 9,6
Page 192 and 193: 190 120 build time (minutes) 100 80
Page 194 and 195: 192 4.2.2 makefs For a source tree
Page 196 and 197: 194 not include later debugging [76
Page 198 and 199: 196 the necessary tools such as mak
Page 200 and 201: 198 proach of supplying alternate c
Page 202 and 203: 200 are not out-of-the-box compatib
Page 204 and 205: 202 golem> mount -t msdos -o rump /
Page 206 and 207: 204 Full OS By a full OS we mean a
Page 208 and 209: 206 • Rapid prototyping: One of t
Page 210 and 211: 208 4.5.3 Testing: Case Studies We
Page 212 and 213: 210 static void scsitest_request(st
Page 214 and 215: 212 waits for the timeout and check
Page 216 and 217: 214 • We noticed that even in sup
Page 218 and 219: 216 which were discovered during wr
Page 222 and 223: 220 It needs to be stressed that Ta
Page 224 and 225: 222 Network clusters Bootstrapping
Page 226 and 227: 224 8 7 Standard components Self-co
Page 228 and 229: 226 Rump kernel calls, as expected,
Page 230 and 231: 228 Traditional FFS We measure the
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Page 234 and 235: 232 The results are presented in Fi
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Page 240 and 241: 238 Rialto [29] is an operating sys
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Page 244 and 245: 242 View OS The View OS [37] approa
Page 246 and 247: 244 OSKit Instead of making system
Page 248 and 249: 246 discussing the type incompatibi
Page 250 and 251: 248 difference to the abovementione
Page 252 and 253: 250 At runtime, a rump kernel can a
Page 254 and 255: 252 For testing and development we
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Page 258 and 259: 256 Art of Virtualization. In: Proc
Page 260 and 261: 258 [30] Adam Dunkels. 2001. Design
Page 262 and 263: 260 [47] Galen C. Hunt and James R.
Page 264 and 265: 262 [67] Steven McCanne and Van Jac
Page 266 and 267: 264 [87] NetBSD Project. URL http:/
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268
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A-2 RUMP.DHCPCLIENT(1) NetBSD Gener
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A-4 RUMP.HALT(1) NetBSD General Com
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A-6 RUMP_SERVER(1) NetBSD General C
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A-8 RUMP_SERVER(1) NetBSD General C
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A-10 SHMIF_DUMPBUS(1) NetBSD Genera
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A-12 P2K(3) NetBSD Library Function
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A-14 P2K(3) NetBSD Library Function
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A-16 RUMP(3) NetBSD Library Functio
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A-18 RUMP(3) NetBSD Library Functio
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A-20 RUMP_ETFS(3) NetBSD Library Fu
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A-22 RUMP_ETFS(3) NetBSD Library Fu
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A-24 RUMP_LWPROC(3) NetBSD Library
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A-26 RUMP_LWPROC(3) NetBSD Library
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A-28 RUMPCLIENT(3) NetBSD Library F
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A-30 RUMPCLIENT(3) NetBSD Library F
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A-32 RUMPHIJACK(3) NetBSD Library F
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A-38 UKFS(3) NetBSD Library Functio
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A-48 SHMIF(4) NetBSD Kernel Interfa
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A-50 RUMP_SP(7) NetBSD Miscellaneou
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A-52 RUMP_SP(7) NetBSD Miscellaneou
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B-2 TCP connections use standard TC
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B-4 rump clients. This means that j
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B-6 ponents. That can be done simpl
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B-8 Our goal is to add another part
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B-10 golem> export RUMP_SERVER=unix
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B-12 golem> rump.dd if=/dev/rcgd0d
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B-14 demogorgon# cgdconfig cgd0 /de
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B-16 rump_server -lrumpnet -lrumpne
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B-18 golem> rump.ifconfig virt0 cre
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B-20 Congratulations, that’s it.
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B-22 purely in userspace, it does n
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B-24 We then proceed to create a mo
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B-26 Then, the only thing left is t
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B-28 -d key=/dk,hostpath=${NFSX}/ff
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B-30 configuration. golem> sh rumpn
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B-32
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C-2 This is a quick fix for making
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C-4 This fixes the conditionally co
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Aalto-DD 171/2012 9HSTFMG*aejbgi+ I
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The Design and Implementation of the Anykernel and Rump Kernels

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