Thread: Version 0.19 released
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From: Shachar S. <rsy...@sh...> - 2006-11-22 05:56:50
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In the best tradition of open source development, "release early, release often". Version 0.19 is now available at all the usual places (i.e. - http://sourceforge.net/projects/rsyncrypto). Go get it while it's hot. This place is probably the place I need to say this least of all, but the main changes this version is introducing are a major speedup to the entire process, on all platforms. OS calls have been buffered for both reads and writes, and the differences are dramatic. For comparison's sake, I created a 16MB file from /dev/urandom. The file is totally uncompressible. Here are some stats from my computer. All stats running on Linux on a Pentium M 1.8GHz. With version 0.18: Encrypting: real 0m14.851s user 0m3.948s sys 0m10.509s We can see that the user space + kernel times make up the entire clock time for the application (the time spent on gzip was not counted here!) We can also see that despite the fact that we are performing heavy operations here (encryption, done in user space), most of the time is spent on system calls. Decryption is much much faster: real 0m3.400s user 0m1.512s sys 0m1.476s We can see that we spend about equal time in the system and in user space. With version 0.19, here are our encryption numbers: real 0m4.251s user 0m4.068s sys 0m0.092s The user space (i.e. - actual encryption) time remained, more or less, the same as before. The system calls time was practically eliminated. The over all execution time was reduced from almost 15 seconds to just a little over 4, making a 3.5 times speedup. The measurements are far from scientific, so your mileage may, and probably will, vary somewhat, but this is clearly a major speedup. As far as decryption times go, things are also looking much better: real 0m1.984s user 0m1.860s sys 0m0.068s As we can see, here too we managed to wipe away all of the time spent on system calls. The relative ratio of system calls wasn't as dramatic here, so we only have about 2 times speedup. This makes particular sense as encryption and decryption do not take different amount of time (though compression does take longer than decompression), so I am fully expecting these numbers to stat approaching the same area. Unfortunately, I don't have a program for Windows that measures user vs. system time, so my measurements there aren't as exact. About the same speedups are seen there, however, so I think it will be safe to assume, for the time being, that the bottlenecks are similar for Linux and for Windows, and optimize the first. Comments, remarks, and I believe that at least one check (someone offered a bug-bounty for getting Windows above 1GB/hr, a mark we clear easily now) welcome. Shachar -- Shachar Shemesh Lingnu Open Source Consulting ltd. Have you backed up today's work? http://www.lingnu.com/backup.html |
From: Julian P. R. <jul...@gm...> - 2006-11-22 13:03:31
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Hi Shachar, Excellent! The performance is now much much better. On my laptop(WinXP), with a Pentium M 1.7GHz, I encrypted a 870Mb Outlook pst file in less than 5 minutes!! At home I have a 3.0 GHz Pentium box. I'll let you know the performance on that fyi. Thanks!! Julian On 22/11/06, Shachar Shemesh <rsy...@sh...> wrote: > > In the best tradition of open source development, "release early, > release often". > > > Version 0.19 is now available at all the usual places (i.e. - > http://sourceforge.net/projects/rsyncrypto). Go get it while it's hot. > > > This place is probably the place I need to say this least of all, but > the main changes this version is introducing are a major speedup to the > entire process, on all platforms. OS calls have been buffered for both > reads and writes, and the differences are dramatic. For comparison's > sake, I created a 16MB file from /dev/urandom. The file is totally > uncompressible. Here are some stats from my computer. All stats running > on Linux on a Pentium M 1.8GHz. > > With version 0.18: > > Encrypting: > > real 0m14.851s > user 0m3.948s > sys 0m10.509s > > > We can see that the user space + kernel times make up the entire clock > time for the application (the time spent on gzip was not counted here!) > We can also see that despite the fact that we are performing heavy > operations here (encryption, done in user space), most of the time is > spent on system calls. Decryption is much much faster: > > real 0m3.400s > user 0m1.512s > sys 0m1.476s > > > We can see that we spend about equal time in the system and in user space. > > > With version 0.19, here are our encryption numbers: > > real 0m4.251s > user 0m4.068s > sys 0m0.092s > > > The user space (i.e. - actual encryption) time remained, more or less, > the same as before. The system calls time was practically eliminated. > The over all execution time was reduced from almost 15 seconds to just a > little over 4, making a 3.5 times speedup. The measurements are far from > scientific, so your mileage may, and probably will, vary somewhat, but > this is clearly a major speedup. > > > As far as decryption times go, things are also looking much better: > > real 0m1.984s > user 0m1.860s > sys 0m0.068s > > > As we can see, here too we managed to wipe away all of the time spent on > system calls. The relative ratio of system calls wasn't as dramatic > here, so we only have about 2 times speedup. This makes particular sense > as encryption and decryption do not take different amount of time > (though compression does take longer than decompression), so I am fully > expecting these numbers to stat approaching the same area. > > > Unfortunately, I don't have a program for Windows that measures user vs. > system time, so my measurements there aren't as exact. About the same > speedups are seen there, however, so I think it will be safe to assume, > for the time being, that the bottlenecks are similar for Linux and for > Windows, and optimize the first. > > > Comments, remarks, and I believe that at least one check (someone > offered a bug-bounty for getting Windows above 1GB/hr, a mark we clear > easily now) welcome. > > > Shachar > > > > -- > Shachar Shemesh > Lingnu Open Source Consulting ltd. > Have you backed up today's work? http://www.lingnu.com/backup.html > > ------------------------------------------------------------------------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share > your > opinions on IT & business topics through brief surveys - and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > _______________________________________________ > Rsyncrypto-devel mailing list > Rsy...@li... > https://lists.sourceforge.net/lists/listinfo/rsyncrypto-devel > |