Date: Fri, 16 Mar 2001 20:07:06 -0500 From: James Housley <jim@thehousleys.net> To: freebsd-arch@freebsd.org Subject: Inherate nodump cause significant slow down of dump Message-ID: <3AB2B8BA.29C5E58E@thehousleys.net> References: <20010316232344.050CB3E1F@bazooka.unixfreak.org>
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The changes to src/sbin/dump/traverse.c (1.10.2.2) cause significant
slow down of the dump estimate phase. Specifically Phase II. My /usr
partition has about 2.5G of data including ports. I had just the
/usr/ports director flagged as nodump. I think that this needs to be
backed out, or fixed before the 4.3-RELEASE.
This is very easy to reproduce. I am assuming that /usr is /dev/ad0s1f
and that ports is on that file system for the following instructions.
For all of these example abort the dump when Phase II finishes with the
"DUMP: estimate ..... blocks.." message appears.
dump 0sf 1048576 /dev/null /dev/ad0s1f
-- this takes 9 seconds to finish Phase II for all versions.
dump 0hsf 0 1048576 /dev/null /dev/ad0s1f
-- this takes 9 seconds to finish Phase II for all versions.
chflags nodump /usr/ports ; dump 0sf 1048576 /dev/null /dev/ad0s1f
-- this takes 9 seconds to finish Phase II for all versions.
chflags nodump /usr/ports ; dump 0hsf 0 1048576 /dev/null /dev/ad0s1f
-- this takes 9 seconds to finish Phase II for version 1.10.2.1 of
src/sbin/dump/traverse.c
chflags nodump /usr/ports ; dump 0hsf 0 1048576 /dev/null /dev/ad0s1f
-- this takes 38 minutes to finish Phase II for version 1.10.2.1 of
src/sbin/dump/traverse.c
A I believe that it is because it repeats once for each file in the
subtree:
msg("mapping (Pass II) [directories]\n");
while (anydirskipped) {
anydirskipped = mapdirs(maxino, &tapesize);
}
I have not yet tested:
chflags -R nodump /usr/ports ; dump 0hsf 0 1048576 /dev/null /dev/ad0s1f
To see if it is quicker. I think the problem may actually be in
mapfiles() and not mapdirs(). The above test will tell me, I am also
going to add a counter in the above loop to verify this theory. However
I am in the middle of a build world back towards a more recent version.
But after dinner I should be able to test this. I welcome independent
testing.
Jim
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