[pacman-dev] pacman -Qs first-run performance

[Philipp Überbacher]

Excerpts from Dan McGee's message of 2011-09-01 20:41:27 +0200:
> On Thu, Sep 1, 2011 at 1:22 PM, Philipp Überbacher
> <hollunder at lavabit.com> wrote:
> > Excerpts from Dan McGee's message of 2011-09-01 19:54:34 +0200:
> >  free -m
> >             total       used       free     shared    buffers     cached
> > Mem:          2002       1080        922          0         17        299
> > -/+ buffers/cache:        763       1239
> > Swap:         2055         98       1956
> Wow- what are you running on a laptop that is keeping 763 MB of RAM
> pegged? Although there appears to be something else in play here.

At least half of that is due to firefox, a music player with a lot of
songs in the playlist (aqualung), smplayer and the mail client (sup)
should account for most of the rest.

> >  hdparm -Tt /dev/sda
> >
> > /dev/sda:
> >  Timing cached reads:   1426 MB in  2.00 seconds = 712.73 MB/sec
> >  Timing buffered disk reads: 166 MB in  3.01 seconds =  55.09 MB/sec
> This is a bit slow, but nothing that should impact your performance that much.
> 
> >  echo 3 > /proc/sys/vm/drop_caches; time pacman -Qs foobarbaz; time pacman -Qs foobarbaz
> >
> > real    1m45.235s
> > user    0m0.127s
> > sys     0m0.590s
> >
> > real    0m0.097s
> > user    0m0.043s
> > sys     0m0.023s
> Can you repeat this and use /usr/bin/time instead of just plain
> "time"? You may have to install the "time" package.

Ah, yes, that was necessary for /usr/bin/time to work.

> echo 3 > /proc/sys/vm/drop_caches; /usr/bin/time pacman -Qs foobarbaz;
> /usr/bin/time pacman -Qs foobarbaz

 echo 3 > /proc/sys/vm/drop_caches; /usr/bin/time pacman -Qs foobarbaz; /usr/bin/time pacman -Qs foobarbaz
Command exited with non-zero status 1
0.08user 0.62system 0:48.48elapsed 1%CPU (0avgtext+0avgdata 3428maxresident)k
173016inputs+0outputs (16major+2353minor)pagefaults 0swaps
Command exited with non-zero status 1
0.02user 0.03system 0:00.08elapsed 78%CPU (0avgtext+0avgdata 3428maxresident)k
0inputs+0outputs (0major+2369minor)pagefaults 0swaps

 echo 3 > /proc/sys/vm/drop_caches; /usr/bin/time pacman -Ss foobarbaz; /usr/bin/time pacman -Ss foobarbaz
Command exited with non-zero status 1
0.19user 0.03system 0:01.51elapsed 14%CPU (0avgtext+0avgdata 8440maxresident)k
9864inputs+0outputs (16major+2177minor)pagefaults 0swaps
Command exited with non-zero status 1
0.19user 0.01system 0:00.27elapsed 76%CPU (0avgtext+0avgdata 8444maxresident)k
0inputs+0outputs (0major+2194minor)pagefaults 0swaps

> Once you do that (but please get the numbers first!), try running
> `pacman-optimize` then rerunning the above test.

 echo 3 > /proc/sys/vm/drop_caches; /usr/bin/time pacman -Qs foobarbaz; /usr/bin/time pacman -Qs foobarbaz
Command exited with non-zero status 1
0.07user 0.46system 0:30.68elapsed 1%CPU (0avgtext+0avgdata 3428maxresident)k
31752inputs+0outputs (16major+2353minor)pagefaults 0swaps
Command exited with non-zero status 1
0.02user 0.04system 0:00.09elapsed 74%CPU (0avgtext+0avgdata 3428maxresident)k
0inputs+0outputs (0major+2369minor)pagefaults 0swaps

 echo 3 > /proc/sys/vm/drop_caches; /usr/bin/time pacman -Ss foobarbaz; /usr/bin/time pacman -Ss foobarbaz
Command exited with non-zero status 1
0.19user 0.02system 0:01.57elapsed 14%CPU (0avgtext+0avgdata 8440maxresident)k
8832inputs+0outputs (16major+2178minor)pagefaults 0swaps
Command exited with non-zero status 1
0.20user 0.00system 0:00.26elapsed 80%CPU (0avgtext+0avgdata 8440maxresident)k
0inputs+0outputs (0major+2193minor)pagefaults 0swaps
 
> Finally, what is the output of df -h for whatever drive /var/lib is
> on? Is it near capacity? And what filesystem with what mount options?

from df -h
/dev/disk/by-uuid/456aa338-0417-43ca-85b2-a03d1b36ec1e ext4       21G   13G  6.2G  68% /

from mtab
/dev/disk/by-uuid/456aa338-0417-43ca-85b2-a03d1b36ec1e / ext4 rw,noatime,user_xattr,acl,barrier=1,nodelalloc,data=ordered 0 0

> >  echo 3 > /proc/sys/vm/drop_caches; time pacman -Ss foobarbaz; time pacman -Ss foobarbaz
> >
> > real    0m1.299s
> > user    0m0.200s
> > sys     0m0.023s
> >
> > real    0m0.252s
> > user    0m0.200s
> > sys     0m0.010s
> 
> At least this one is OK.
> 
> -Dan

Ok, thanks a lot Dan and everyone else.

Regards,
Philipp