Contents of /alx-src/trunk/kernel26-alx/linux/Documentation/RCU/RTFP.txt
Parent Directory | Revision Log
Revision 628 -
(show annotations)
(download)
Wed Mar 4 10:48:58 2009 UTC (15 years, 1 month ago) by niro
File MIME type: text/plain
File size: 14580 byte(s)
Wed Mar 4 10:48:58 2009 UTC (15 years, 1 month ago) by niro
File MIME type: text/plain
File size: 14580 byte(s)
import linux sources based on 2.6.12-alx-r9: -using linux-2.6.12.6 -using 2.6.12-ck6 patch set -using fbsplash-0.9.2-r3 -using vesafb-tng-0.9-rc7 -using squashfs-2.2 -added cddvd-cmdfilter-drop.patch as ck dropped it -added via-epia-dri (cle266) patch -added zd1211-svn-32 wlan driver (http://zd1211.ath.cx/download/) -added debian patches to zd1211 for wep256 etc
1 | Read the F-ing Papers! |
2 | |
3 | |
4 | This document describes RCU-related publications, and is followed by |
5 | the corresponding bibtex entries. |
6 | |
7 | The first thing resembling RCU was published in 1980, when Kung and Lehman |
8 | [Kung80] recommended use of a garbage collector to defer destruction |
9 | of nodes in a parallel binary search tree in order to simplify its |
10 | implementation. This works well in environments that have garbage |
11 | collectors, but current production garbage collectors incur significant |
12 | read-side overhead. |
13 | |
14 | In 1982, Manber and Ladner [Manber82,Manber84] recommended deferring |
15 | destruction until all threads running at that time have terminated, again |
16 | for a parallel binary search tree. This approach works well in systems |
17 | with short-lived threads, such as the K42 research operating system. |
18 | However, Linux has long-lived tasks, so more is needed. |
19 | |
20 | In 1986, Hennessy, Osisek, and Seigh [Hennessy89] introduced passive |
21 | serialization, which is an RCU-like mechanism that relies on the presence |
22 | of "quiescent states" in the VM/XA hypervisor that are guaranteed not |
23 | to be referencing the data structure. However, this mechanism was not |
24 | optimized for modern computer systems, which is not surprising given |
25 | that these overheads were not so expensive in the mid-80s. Nonetheless, |
26 | passive serialization appears to be the first deferred-destruction |
27 | mechanism to be used in production. Furthermore, the relevant patent has |
28 | lapsed, so this approach may be used in non-GPL software, if desired. |
29 | (In contrast, use of RCU is permitted only in software licensed under |
30 | GPL. Sorry!!!) |
31 | |
32 | In 1990, Pugh [Pugh90] noted that explicitly tracking which threads |
33 | were reading a given data structure permitted deferred free to operate |
34 | in the presence of non-terminating threads. However, this explicit |
35 | tracking imposes significant read-side overhead, which is undesirable |
36 | in read-mostly situations. This algorithm does take pains to avoid |
37 | write-side contention and parallelize the other write-side overheads by |
38 | providing a fine-grained locking design, however, it would be interesting |
39 | to see how much of the performance advantage reported in 1990 remains |
40 | in 2004. |
41 | |
42 | At about this same time, Adams [Adams91] described ``chaotic relaxation'', |
43 | where the normal barriers between successive iterations of convergent |
44 | numerical algorithms are relaxed, so that iteration $n$ might use |
45 | data from iteration $n-1$ or even $n-2$. This introduces error, |
46 | which typically slows convergence and thus increases the number of |
47 | iterations required. However, this increase is sometimes more than made |
48 | up for by a reduction in the number of expensive barrier operations, |
49 | which are otherwise required to synchronize the threads at the end |
50 | of each iteration. Unfortunately, chaotic relaxation requires highly |
51 | structured data, such as the matrices used in scientific programs, and |
52 | is thus inapplicable to most data structures in operating-system kernels. |
53 | |
54 | In 1993, Jacobson [Jacobson93] verbally described what is perhaps the |
55 | simplest deferred-free technique: simply waiting a fixed amount of time |
56 | before freeing blocks awaiting deferred free. Jacobson did not describe |
57 | any write-side changes he might have made in this work using SGI's Irix |
58 | kernel. Aju John published a similar technique in 1995 [AjuJohn95]. |
59 | This works well if there is a well-defined upper bound on the length of |
60 | time that reading threads can hold references, as there might well be in |
61 | hard real-time systems. However, if this time is exceeded, perhaps due |
62 | to preemption, excessive interrupts, or larger-than-anticipated load, |
63 | memory corruption can ensue, with no reasonable means of diagnosis. |
64 | Jacobson's technique is therefore inappropriate for use in production |
65 | operating-system kernels, except when such kernels can provide hard |
66 | real-time response guarantees for all operations. |
67 | |
68 | Also in 1995, Pu et al. [Pu95a] applied a technique similar to that of Pugh's |
69 | read-side-tracking to permit replugging of algorithms within a commercial |
70 | Unix operating system. However, this replugging permitted only a single |
71 | reader at a time. The following year, this same group of researchers |
72 | extended their technique to allow for multiple readers [Cowan96a]. |
73 | Their approach requires memory barriers (and thus pipeline stalls), |
74 | but reduces memory latency, contention, and locking overheads. |
75 | |
76 | 1995 also saw the first publication of DYNIX/ptx's RCU mechanism |
77 | [Slingwine95], which was optimized for modern CPU architectures, |
78 | and was successfully applied to a number of situations within the |
79 | DYNIX/ptx kernel. The corresponding conference paper appeared in 1998 |
80 | [McKenney98]. |
81 | |
82 | In 1999, the Tornado and K42 groups described their "generations" |
83 | mechanism, which quite similar to RCU [Gamsa99]. These operating systems |
84 | made pervasive use of RCU in place of "existence locks", which greatly |
85 | simplifies locking hierarchies. |
86 | |
87 | 2001 saw the first RCU presentation involving Linux [McKenney01a] |
88 | at OLS. The resulting abundance of RCU patches was presented the |
89 | following year [McKenney02a], and use of RCU in dcache was first |
90 | described that same year [Linder02a]. |
91 | |
92 | Also in 2002, Michael [Michael02b,Michael02a] presented techniques |
93 | that defer the destruction of data structures to simplify non-blocking |
94 | synchronization (wait-free synchronization, lock-free synchronization, |
95 | and obstruction-free synchronization are all examples of non-blocking |
96 | synchronization). In particular, this technique eliminates locking, |
97 | reduces contention, reduces memory latency for readers, and parallelizes |
98 | pipeline stalls and memory latency for writers. However, these |
99 | techniques still impose significant read-side overhead in the form of |
100 | memory barriers. Researchers at Sun worked along similar lines in the |
101 | same timeframe [HerlihyLM02,HerlihyLMS03]. |
102 | |
103 | In 2003, the K42 group described how RCU could be used to create |
104 | hot-pluggable implementations of operating-system functions. Later that |
105 | year saw a paper describing an RCU implementation of System V IPC |
106 | [Arcangeli03], and an introduction to RCU in Linux Journal [McKenney03a]. |
107 | |
108 | 2004 has seen a Linux-Journal article on use of RCU in dcache |
109 | [McKenney04a], a performance comparison of locking to RCU on several |
110 | different CPUs [McKenney04b], a dissertation describing use of RCU in a |
111 | number of operating-system kernels [PaulEdwardMcKenneyPhD], a paper |
112 | describing how to make RCU safe for soft-realtime applications [Sarma04c], |
113 | and a paper describing SELinux performance with RCU [JamesMorris04b]. |
114 | |
115 | |
116 | Bibtex Entries |
117 | |
118 | @article{Kung80 |
119 | ,author="H. T. Kung and Q. Lehman" |
120 | ,title="Concurrent Maintenance of Binary Search Trees" |
121 | ,Year="1980" |
122 | ,Month="September" |
123 | ,journal="ACM Transactions on Database Systems" |
124 | ,volume="5" |
125 | ,number="3" |
126 | ,pages="354-382" |
127 | } |
128 | |
129 | @techreport{Manber82 |
130 | ,author="Udi Manber and Richard E. Ladner" |
131 | ,title="Concurrency Control in a Dynamic Search Structure" |
132 | ,institution="Department of Computer Science, University of Washington" |
133 | ,address="Seattle, Washington" |
134 | ,year="1982" |
135 | ,number="82-01-01" |
136 | ,month="January" |
137 | ,pages="28" |
138 | } |
139 | |
140 | @article{Manber84 |
141 | ,author="Udi Manber and Richard E. Ladner" |
142 | ,title="Concurrency Control in a Dynamic Search Structure" |
143 | ,Year="1984" |
144 | ,Month="September" |
145 | ,journal="ACM Transactions on Database Systems" |
146 | ,volume="9" |
147 | ,number="3" |
148 | ,pages="439-455" |
149 | } |
150 | |
151 | @techreport{Hennessy89 |
152 | ,author="James P. Hennessy and Damian L. Osisek and Joseph W. {Seigh II}" |
153 | ,title="Passive Serialization in a Multitasking Environment" |
154 | ,institution="US Patent and Trademark Office" |
155 | ,address="Washington, DC" |
156 | ,year="1989" |
157 | ,number="US Patent 4,809,168 (lapsed)" |
158 | ,month="February" |
159 | ,pages="11" |
160 | } |
161 | |
162 | @techreport{Pugh90 |
163 | ,author="William Pugh" |
164 | ,title="Concurrent Maintenance of Skip Lists" |
165 | ,institution="Institute of Advanced Computer Science Studies, Department of Computer Science, University of Maryland" |
166 | ,address="College Park, Maryland" |
167 | ,year="1990" |
168 | ,number="CS-TR-2222.1" |
169 | ,month="June" |
170 | } |
171 | |
172 | @Book{Adams91 |
173 | ,Author="Gregory R. Adams" |
174 | ,title="Concurrent Programming, Principles, and Practices" |
175 | ,Publisher="Benjamin Cummins" |
176 | ,Year="1991" |
177 | } |
178 | |
179 | @unpublished{Jacobson93 |
180 | ,author="Van Jacobson" |
181 | ,title="Avoid Read-Side Locking Via Delayed Free" |
182 | ,year="1993" |
183 | ,month="September" |
184 | ,note="Verbal discussion" |
185 | } |
186 | |
187 | @Conference{AjuJohn95 |
188 | ,Author="Aju John" |
189 | ,Title="Dynamic vnodes -- Design and Implementation" |
190 | ,Booktitle="{USENIX Winter 1995}" |
191 | ,Publisher="USENIX Association" |
192 | ,Month="January" |
193 | ,Year="1995" |
194 | ,pages="11-23" |
195 | ,Address="New Orleans, LA" |
196 | } |
197 | |
198 | @techreport{Slingwine95 |
199 | ,author="John D. Slingwine and Paul E. McKenney" |
200 | ,title="Apparatus and Method for Achieving Reduced Overhead Mutual |
201 | Exclusion and Maintaining Coherency in a Multiprocessor System |
202 | Utilizing Execution History and Thread Monitoring" |
203 | ,institution="US Patent and Trademark Office" |
204 | ,address="Washington, DC" |
205 | ,year="1995" |
206 | ,number="US Patent 5,442,758 (contributed under GPL)" |
207 | ,month="August" |
208 | } |
209 | |
210 | @techreport{Slingwine97 |
211 | ,author="John D. Slingwine and Paul E. McKenney" |
212 | ,title="Method for maintaining data coherency using thread |
213 | activity summaries in a multicomputer system" |
214 | ,institution="US Patent and Trademark Office" |
215 | ,address="Washington, DC" |
216 | ,year="1997" |
217 | ,number="US Patent 5,608,893 (contributed under GPL)" |
218 | ,month="March" |
219 | } |
220 | |
221 | @techreport{Slingwine98 |
222 | ,author="John D. Slingwine and Paul E. McKenney" |
223 | ,title="Apparatus and method for achieving reduced overhead |
224 | mutual exclusion and maintaining coherency in a multiprocessor |
225 | system utilizing execution history and thread monitoring" |
226 | ,institution="US Patent and Trademark Office" |
227 | ,address="Washington, DC" |
228 | ,year="1998" |
229 | ,number="US Patent 5,727,209 (contributed under GPL)" |
230 | ,month="March" |
231 | } |
232 | |
233 | @Conference{McKenney98 |
234 | ,Author="Paul E. McKenney and John D. Slingwine" |
235 | ,Title="Read-Copy Update: Using Execution History to Solve Concurrency |
236 | Problems" |
237 | ,Booktitle="{Parallel and Distributed Computing and Systems}" |
238 | ,Month="October" |
239 | ,Year="1998" |
240 | ,pages="509-518" |
241 | ,Address="Las Vegas, NV" |
242 | } |
243 | |
244 | @Conference{Gamsa99 |
245 | ,Author="Ben Gamsa and Orran Krieger and Jonathan Appavoo and Michael Stumm" |
246 | ,Title="Tornado: Maximizing Locality and Concurrency in a Shared Memory |
247 | Multiprocessor Operating System" |
248 | ,Booktitle="{Proceedings of the 3\textsuperscript{rd} Symposium on |
249 | Operating System Design and Implementation}" |
250 | ,Month="February" |
251 | ,Year="1999" |
252 | ,pages="87-100" |
253 | ,Address="New Orleans, LA" |
254 | } |
255 | |
256 | @techreport{Slingwine01 |
257 | ,author="John D. Slingwine and Paul E. McKenney" |
258 | ,title="Apparatus and method for achieving reduced overhead |
259 | mutual exclusion and maintaining coherency in a multiprocessor |
260 | system utilizing execution history and thread monitoring" |
261 | ,institution="US Patent and Trademark Office" |
262 | ,address="Washington, DC" |
263 | ,year="2001" |
264 | ,number="US Patent 5,219,690 (contributed under GPL)" |
265 | ,month="April" |
266 | } |
267 | |
268 | @Conference{McKenney01a |
269 | ,Author="Paul E. McKenney and Jonathan Appavoo and Andi Kleen and |
270 | Orran Krieger and Rusty Russell and Dipankar Sarma and Maneesh Soni" |
271 | ,Title="Read-Copy Update" |
272 | ,Booktitle="{Ottawa Linux Symposium}" |
273 | ,Month="July" |
274 | ,Year="2001" |
275 | ,note="Available: |
276 | \url{http://www.linuxsymposium.org/2001/abstracts/readcopy.php} |
277 | \url{http://www.rdrop.com/users/paulmck/rclock/rclock_OLS.2001.05.01c.pdf} |
278 | [Viewed June 23, 2004]" |
279 | annotation=" |
280 | Described RCU, and presented some patches implementing and using it in |
281 | the Linux kernel. |
282 | " |
283 | } |
284 | |
285 | @Conference{Linder02a |
286 | ,Author="Hanna Linder and Dipankar Sarma and Maneesh Soni" |
287 | ,Title="Scalability of the Directory Entry Cache" |
288 | ,Booktitle="{Ottawa Linux Symposium}" |
289 | ,Month="June" |
290 | ,Year="2002" |
291 | ,pages="289-300" |
292 | } |
293 | |
294 | @Conference{McKenney02a |
295 | ,Author="Paul E. McKenney and Dipankar Sarma and |
296 | Andrea Arcangeli and Andi Kleen and Orran Krieger and Rusty Russell" |
297 | ,Title="Read-Copy Update" |
298 | ,Booktitle="{Ottawa Linux Symposium}" |
299 | ,Month="June" |
300 | ,Year="2002" |
301 | ,pages="338-367" |
302 | ,note="Available: |
303 | \url{http://www.linux.org.uk/~ajh/ols2002_proceedings.pdf.gz} |
304 | [Viewed June 23, 2004]" |
305 | } |
306 | |
307 | @article{Appavoo03a |
308 | ,author="J. Appavoo and K. Hui and C. A. N. Soules and R. W. Wisniewski and |
309 | D. M. {Da Silva} and O. Krieger and M. A. Auslander and D. J. Edelsohn and |
310 | B. Gamsa and G. R. Ganger and P. McKenney and M. Ostrowski and |
311 | B. Rosenburg and M. Stumm and J. Xenidis" |
312 | ,title="Enabling Autonomic Behavior in Systems Software With Hot Swapping" |
313 | ,Year="2003" |
314 | ,Month="January" |
315 | ,journal="IBM Systems Journal" |
316 | ,volume="42" |
317 | ,number="1" |
318 | ,pages="60-76" |
319 | } |
320 | |
321 | @Conference{Arcangeli03 |
322 | ,Author="Andrea Arcangeli and Mingming Cao and Paul E. McKenney and |
323 | Dipankar Sarma" |
324 | ,Title="Using Read-Copy Update Techniques for {System V IPC} in the |
325 | {Linux} 2.5 Kernel" |
326 | ,Booktitle="Proceedings of the 2003 USENIX Annual Technical Conference |
327 | (FREENIX Track)" |
328 | ,Publisher="USENIX Association" |
329 | ,year="2003" |
330 | ,month="June" |
331 | ,pages="297-310" |
332 | } |
333 | |
334 | @article{McKenney03a |
335 | ,author="Paul E. McKenney" |
336 | ,title="Using {RCU} in the {Linux} 2.5 Kernel" |
337 | ,Year="2003" |
338 | ,Month="October" |
339 | ,journal="Linux Journal" |
340 | ,volume="1" |
341 | ,number="114" |
342 | ,pages="18-26" |
343 | } |
344 | |
345 | @techreport{Friedberg03a |
346 | ,author="Stuart A. Friedberg" |
347 | ,title="Lock-Free Wild Card Search Data Structure and Method" |
348 | ,institution="US Patent and Trademark Office" |
349 | ,address="Washington, DC" |
350 | ,year="2003" |
351 | ,number="US Patent 6,662,184 (contributed under GPL)" |
352 | ,month="December" |
353 | ,pages="112" |
354 | } |
355 | |
356 | @article{McKenney04a |
357 | ,author="Paul E. McKenney and Dipankar Sarma and Maneesh Soni" |
358 | ,title="Scaling dcache with {RCU}" |
359 | ,Year="2004" |
360 | ,Month="January" |
361 | ,journal="Linux Journal" |
362 | ,volume="1" |
363 | ,number="118" |
364 | ,pages="38-46" |
365 | } |
366 | |
367 | @Conference{McKenney04b |
368 | ,Author="Paul E. McKenney" |
369 | ,Title="{RCU} vs. Locking Performance on Different {CPUs}" |
370 | ,Booktitle="{linux.conf.au}" |
371 | ,Month="January" |
372 | ,Year="2004" |
373 | ,Address="Adelaide, Australia" |
374 | ,note="Available: |
375 | \url{http://www.linux.org.au/conf/2004/abstracts.html#90} |
376 | \url{http://www.rdrop.com/users/paulmck/rclock/lockperf.2004.01.17a.pdf} |
377 | [Viewed June 23, 2004]" |
378 | } |
379 | |
380 | @phdthesis{PaulEdwardMcKenneyPhD |
381 | ,author="Paul E. McKenney" |
382 | ,title="Exploiting Deferred Destruction: |
383 | An Analysis of Read-Copy-Update Techniques |
384 | in Operating System Kernels" |
385 | ,school="OGI School of Science and Engineering at |
386 | Oregon Health and Sciences University" |
387 | ,year="2004" |
388 | ,note="Available: |
389 | \url{http://www.rdrop.com/users/paulmck/RCU/RCUdissertation.2004.07.14e1.pdf} |
390 | [Viewed October 15, 2004]" |
391 | } |
392 | |
393 | @Conference{Sarma04c |
394 | ,Author="Dipankar Sarma and Paul E. McKenney" |
395 | ,Title="Making RCU Safe for Deep Sub-Millisecond Response Realtime Applications" |
396 | ,Booktitle="Proceedings of the 2004 USENIX Annual Technical Conference |
397 | (FREENIX Track)" |
398 | ,Publisher="USENIX Association" |
399 | ,year="2004" |
400 | ,month="June" |
401 | ,pages="182-191" |
402 | } |
403 | |
404 | @unpublished{JamesMorris04b |
405 | ,Author="James Morris" |
406 | ,Title="Recent Developments in {SELinux} Kernel Performance" |
407 | ,month="December" |
408 | ,year="2004" |
409 | ,note="Available: |
410 | \url{http://www.livejournal.com/users/james_morris/2153.html} |
411 | [Viewed December 10, 2004]" |
412 | } |