On Sun, 18 Sep 2011 08:47:13 +0200 Ronald Klop wrote:
RK> On Sun, 18 Sep 2011 07:39:01 +0200, Jeremy Chadwick
RK> <free...@jdc.parodius.com> wrote:
>> On Sun, Sep 18, 2011 at 12:54:13AM -0400, Jason Hellenthal wrote:
>>> On Sun, Sep 18, 2011 at 01:49:15AM +0200, Ronald Klop wrote:
>>> > Hi,
>>> >
>>> > I'm running portupgrade in screen to update all the ports for
>>> > 9-BETA2/9-CURRENT on amd64. While doing this script eats 100%
cpu.
>>> > Because portupgrade -fa crashed I'm running this command to
update the
>>> > remaining non-updates ports.
>>> > find /var/db/pkg -name +DESC -mtime +2 |cut -d / -f 5 | xargs
>>> time nice -n
>>> > 20 portupgrade -f
>>> >
>>> > The output of truss -p `pgrep script` is this:
>>> > clock_gettime(13,{1316301104.000000000 }) = 0 (0x0)
>>> > select(5,{0 4},0x0,0x0,{30.000000 }) = 1 (0x1)
>>> > read(0,0x7fffffffcdf0,1024) = 0 (0x0)
>>> > write(4,0x7fffffffcdf0,0) = 0 (0x0)
>>> > clock_gettime(13,{1316301104.000000000 }) = 0 (0x0)
>>> > select(5,{0 4},0x0,0x0,{30.000000 }) = 1 (0x1)
>>> > read(0,0x7fffffffcdf0,1024) = 0 (0x0)
>>> > write(4,0x7fffffffcdf0,0) = 0 (0x0)
>>> > clock_gettime(13,{1316301104.000000000 }) = 0 (0x0)
>>> > select(5,{0 4},0x0,0x0,{30.000000 }) = 1 (0x1)
>>> > read(0,0x7fffffffcdf0,1024) = 0 (0x0)
>>> > write(4,0x7fffffffcdf0,0) = 0 (0x0)
>>> > clock_gettime(13,{1316301104.000000000 }) = 0 (0x0)
>>> > select(5,{0 4},0x0,0x0,{30.000000 }) = 1 (0x1)
>>> > read(0,0x7fffffffcdf0,1024) = 0 (0x0)
>>> > write(4,0x7fffffffcdf0,0) = 0 (0x0)
>>> >
>>> > So it is really fast in reading and writing 0 bytes most of the
time.
>>> >
>>> > I also found
>>> http://web.archiveorange.com/archive/v/6ETvLvjo60Gj9geAUAb6
>>> > and I think I am better of by rewriting my command so
stdin/stdout is
>>> > still the terminal. Although the link is a couple of years old.
>>> >
>>> > Is this known? Can somebody explain me why my xargs command is
>>> not working
>>> > well?
>>> >
>>>
>>> Are you absolutely sure that its script(1) causing this ? 100% CPU
usage
>>> has been a known side effect of screen(1) for quite some time.
Rebuild
>>> it and try again.
>>
>> Jason's referring to this, I believe:
>>
http://www.freebsd.org/cgi/cvsweb.cgi/ports/sysutils/screen/Makefile#rev1.55
>>
>> To clarify the what the commit message means: it does not mean
"when the
>> package is installed the installation takes up 100% CPU". It means
>> "once the package is installed and screen is used, screen takes up
100%
>> CPU". I know because I've seen this behaviour in the past (one of
the
>> many, many reasons I build ports from source).
>>
>> However:
>>
http://www.freebsd.org/cgi/cvsweb.cgi/ports/sysutils/screen/Makefile#rev1.78
>>
>> So: If a binary package is being installed through your above
>> portupgrade command, and you're seeing this problem, then it sounds
to
>> me like commit revision 1.78 is a regression and NO_PACKAGE should
be
>> put back into place + packages removed from all mirrors.
>>
>> There are many reasons to not use GNU screen at all, or if you must
have
>> something like it, use tmux. I recently had to provide an analysis
of
>> how GNU screen destroys one's terminal[1]; so if the above problem
turns
>> out to be caused by GNU screen as well, I'll just add it to my
>> ever-growing list of reasons the software should be nuked from
orbit.
>>
>> Otherwise, if this turns out to be a problem with portupgrade
(which you
>> found some evidence supporting such), then the solution is simple:
stop
>> using portupgrade, use portmaster (if it lacks things you need ask
Doug
>> Barton, he's incredibly receptive to adding new features/fixing
things).
>> Two databases that aren't compatible, ruby shims, and other crap =
not
>> worth it. Think the database ordeal is long over
with/fixed/whatever?
>> It isn't[2].
>>
>> [1]:
>>
http://lists.freebsd.org/pipermail/freebsd-stable/2011-June/063052.html
>> [2]:
>>
http://www.dslreports.com/forum/r26304856-FreeBSD-defining-portmaster-alias
>>
RK> I have a repeatable test. Run top in a window and this command in
another.
RK> $ echo test | script /tmp/script-test sleep 1000
RK> Script started, output file is /tmp/script-test
RK> test
RK> PID USERNAME THR PRI NICE SIZE RES STATE C TIME
RK> CPU COMMAND
RK> 29656 ronald 1 103 0 12324K 1244K CPU4 4 1:03
RK> 100.00% script
RK> So it has nothing to do with portupgrade or screen. The output of
RK> truss -p29656 is the same as posted previously.
I believe the behaviour is after this commit:
http://svnweb.freebsd.org/base?view=revision&revision=125848
I think we should skip select on STDIN after reading EOF from it, like
in the
patch below.
