Date: Tue, 5 Aug 2008 21:00:09 GMT From: Jakub Jasinski <jakub.jasinski@utoronto.ca> To: freebsd-bugs@FreeBSD.org Subject: Re: misc/126230: weird process cpu usage stats and weird load average Message-ID: <200808052100.m75L09YV005786@freefall.freebsd.org>
index | next in thread | raw e-mail
The following reply was made to PR misc/126230; it has been noted by GNATS.
From: Jakub Jasinski <jakub.jasinski@utoronto.ca>
To: Kris Kennaway <kris@FreeBSD.org>
Cc: freebsd-gnats-submit@FreeBSD.org
Subject: Re: misc/126230: weird process cpu usage stats and weird load
average
Date: Tue, 5 Aug 2008 17:05:11 -0400
It looks like a select-related bug.
I compiled the sample select program (except that it waits for 120
seconds):
#include <stdio.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
int
main(void)
{
fd_set rfds;
struct timeval tv;
int retval;
/* Watch stdin (fd 0) to see when it has input. */
FD_ZERO(&rfds);
FD_SET(0, &rfds);
/* Wait up to five seconds. */
tv.tv_sec = 120;
tv.tv_usec = 0;
retval = select(1, &rfds, NULL, NULL, &tv);
/* Don't rely on the value of tv now! */
if (retval == -1)
perror("select()");
else if (retval)
printf("Data is available now.\n");
/* FD_ISSET(0, &rfds) will be true. */
else
printf("No data within 120 seconds.\n");
return 0;
}
And this is what I get after running rsync:
last pid: 1193; load averages: 0.00, 0.00, 0.00 up 0
+01:47:18 16:51:41 63 processes: 1 running, 62 sleeping
CPU states: 0.3% user, 0.0% nice, 19.7% system, 1.0% interrupt,
78.9% idle Mem: 146M Active, 236M Inact, 247M Wired, 116K Cache, 214M
Buf, 7284M Free Swap: 8192M Total, 8192M Free
PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU
COMMAN
590 root 2 4 0 14112K 2516K select 2 0:20 9.42% apcupsd
1193 root 1 -16 0 17196K 12176K wdrain 0 0:03 8.15% rsync
767 root 1 4 0 30108K 5208K select 0 0:12 5.96% sendmail
684 root 1 4 0 9940K 1260K select 3 0:11 5.08% authdaemond
1192 root 1 46 0 7656K 2192K CPU0 0 0:01 3.66% top
1188 admin 1 4 0 2532K 660K select 3 0:02 3.56% a.out
[snipped]
a.out is consuming 3.56% while select-ing. That's funny. :)
On Tue, 5 Aug 2008 18:10:03 GMT
Kris Kennaway <kris@FreeBSD.org> wrote:
> The following reply was made to PR misc/126230; it has been noted by
> GNATS.
>
> From: Kris Kennaway <kris@FreeBSD.org>
> To: Jakub Jasinski <jakub.jasinski@utoronto.ca>
> Cc: freebsd-gnats-submit@FreeBSD.org
> Subject: Re: misc/126230: weird process cpu usage stats and weird
> load average Date: Tue, 05 Aug 2008 20:08:36 +0200
>
> Jakub Jasinski wrote:
> > uhci2: <Intel 631XESB/632XESB/3100 USB controller USB-3> port
> > 0x1040-0x105f irq 18 at device 29.2 on pci0 uhci2: [GIANT-LOCKED]
> > uhci2: [ITHREAD]
> > usb2: <Intel 631XESB/632XESB/3100 USB controller USB-3> on uhci2
> > usb2: USB revision 1.0
> > uhub2: <Intel UHCI root hub, class 9/0, rev 1.00/1.00, addr 1> on
> > usb2 uhub2: 2 ports with 2 removable, self powered
> > ukbd0: <No brand KVM A1, class 0/0, rev 1.10/0.00, addr 2> on uhub2
> > kbd2 at ukbd0
> > ums0: <No brand KVM A1, class 0/0, rev 1.10/0.00, addr 2> on uhub2
> > ums0: 5 buttons and Z dir.
> >
> > Ok, so the keyboard and mouse are there. I detached them, killed
> > moused, rerun rsync and I got the same weird top output:
>
> Are the devices still attached (i.e. did they detach)? What if you
> compile a kernel with no USB support at all (obviously you won't be
> able to log in with a USB keyboard, but you can still log in
> remotely).
> Kris
>
>
> >
> > FreeBSD 7.0-RELEASE (CUSTOM) #2: Mon Aug 4 12:44:23 EDT 2008
> > last pid: 1258; load averages: 0.00, 0.00, 0.00 up 0
> > +01:09:53 13:20:17 last pid: 1266; load averages: 1.98, 0.55,
> > 0.20 up 0 +01:11:33 13:21:57 58 processes: 1 running, 57
> > sleeping CPU states: 0.9% user, 0.0% nice, 36.0% system, 3.5%
> > interrupt, 59.6% idle Mem: 142M Active, 59M Inact, 278M Wired, 48K
> > Cache, 214M Buf, 7433M Free Swap: 8192M Total, 8192M Free
> >
> > PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU
> > COMMAND
> > 662 root 2 4 0 14112K 2504K select 3 0:15 12.65% apcupsd
> > 1266 root 1 54 0 17196K 12112K select 0 0:03 10.50% rsync
> > 756 root 1 4 0 9940K 1260K select 2 0:08 6.40% authdaemon
> > 1259 root 1 48 0 7656K 2328K CPU1 1 0:02 5.27% top
> > 981 root 1 4 0 30108K 5292K select 2 0:06 4.59% sendmail
> > 1265 root 1 4 0 17196K 11824K select 3 0:02 4.59% rsync
> > 790 root 1 4 0 9940K 1260K select 1 0:06 4.49% authdaemon
> > 774 root 1 4 0 3604K 1220K select 2 0:06 4.49% couriertcp
> > 791 root 1 4 0 9940K 1260K select 0 0:06 4.49% authdaemon
> >
> > etc.
> >
> > ...and why are apcupsd (connected via serial port), syslogd,
> > couriertcpd, sendmail, etc. working a the _exact_ same time for the
> > same duration at around the same WPCU%?
> >
> > Just for comparison, this is a summary of top on FreeBSD 6.2 (32
> > bit) on another non-deployed box running pretty much the same
> > software (courier imap, clamav, spamassassin, etc.) after rsync is
> > activated: 43.48% for one rsync process
> > 1.96% for another
> > 0.00% for everything else.
> >
> > On Tue, 5 Aug 2008 16:50:04 GMT
> > Kris Kennaway <kris@FreeBSD.org> wrote:
> >
> >> Jakub Jasinski wrote:
> >> > I recompiled the kernel with the ULE scheduler and the only
> >> > difference now is that every 'working' process has higher WCPU
> >> > _after_ rsync is activated. Before rsync is activated all
> >> > process have 0% WCPU.
> >> >
> >> > BTW, thanks for the help.
> >> >
> >> > [root@mail2 ~]# vmstat -i
> >> > interrupt total rate
> >> > irq1: atkbd0 78 0
> >> > irq4: sio0 2023 5
> >> > irq14: ata0 58 0
> >> > irq16: uhci0 ehci0 1 0
> >> > irq18: ciss0 uhci2 2618 6
> >> > irq22: uhci4 19 0
> >> > cpu0: timer 751994 1994
> >> > irq257: bce1 2271 6
> >> > cpu1: timer 744491 1974
> >> > cpu2: timer 744494 1974
> >> > cpu3: timer 744513 1974
> >> > Total 2992560 7937
> >>
> >> Your system is sharing an interrupt between the ciss and one of
> >> the USB controllers. This means that every time there is an
> >> interrupt from disk I/O the USB drivers will also wake up to
> >> process it. This could be causing things like moused and cups to
> >> run. What devices are attached to uhci2?
> >>
> >
> >
>
> _______________________________________________
> freebsd-bugs@freebsd.org mailing list
> http://lists.freebsd.org/mailman/listinfo/freebsd-bugs
> To unsubscribe, send any mail to
> "freebsd-bugs-unsubscribe@freebsd.org"
help
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200808052100.m75L09YV005786>