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Re: svnadmin taking a break?

From: Konstantin Kolinko <knst.kolinko_at_gmail.com>
Date: Thu, 29 Oct 2009 04:25:58 +0300

2009/10/28 Carsten Heyl <cal_at_pixelboxx.de>:
> Hi subversion users and supporters!
>
> First a big thanks to the subversion team!
> Please continue your great work!
>
> Currently I test converting a cvs repository to svn.
> The cvs2svn took 15 hours and the dump file is about 12 GB.
> Nothing special here.
>
> Than I took svnadmin to load the dumpfile into a new repository
>
> svnadmin create --fs-type fsfs svnroot
> svnadmin load -q ${PWD}/svnroot <cvs2svn-out.dump
>
> System: Linux 2.6.22.19-0.2-bigsmp (opensuse 10.3), xfs filesystem
>
> I expected the svnadmin to be either busy or waiting for io but most of
> the time
> the percentage of "idle" is above 50 %.
>
> A short strace shows that reading from stdin is done "by byte":
>(...)
> That may be a problem.
> (Try that on NFS ...)
>
> Doing a strace -c on svnadmin running for a few minutes (!) gave:
>
> % time     seconds  usecs/call     calls    errors syscall
> ------ ----------- ----------- --------- --------- ----------------
>  56.22    3.304842           2   1893895           close
>  22.81    1.341002          16     81366           fsync
>  13.98    0.821780          40     20656           fdatasync
>  2.77    0.162701           0   1929533     35634 open
>  1.67    0.098424           1    181236      6303 unlink
>  1.31    0.076992           0  11349854           read
>  0.51    0.030215           0   1093822           write
>  0.26    0.015424           0     62457           rename
>  0.22    0.012863           0    749347           lstat64
>  0.07    0.004116           0     25406           getdents64
>  0.05    0.003233           1      6303           rmdir
>  0.04    0.002594           0    875977           lseek
>  0.03    0.001832           0    308237           fcntl64
>  0.02    0.001030           0     31529           chmod
>  0.01    0.000523           0     35893     35893 access
>  0.01    0.000420           0     31529           stat64
>  0.00    0.000251           0     86064           fstat64
>  0.00    0.000231           0      6317           mkdir
>  0.00    0.000190           0      4390           ftruncate
>  0.00    0.000000           0       433           brk
>  0.00    0.000000           0     12606           gettimeofday
> ------ ----------- ----------- --------- --------- ----------------
> 100.00    5.878663              18786850     77830 total
>
> So that does not point to read.
> But 6 seconds of 5-10 minutes elapsed time spend in system calls?
>
> Where does svnadmin spend it's time?
>

Don't know whether I am right, just remembered a recent message here
regarding SQLite performance:
http://subversion.tigris.org/ds/viewMessage.do?dsForumId=462&dsMessageId=2405325

SQLite uses fsync calls:
http://www.sqlite.org/lockingv3.html#how_to_corrupt

Best regards,
Konstantin Kolinko

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Received on 2009-10-29 02:27:03 CET

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