Ubuntu Performance Question

[Tyler Aviss]

You can also check DMA on the drive using

hdparm -d /dev/hda (substitute you drive as appropriate, doesn't apply
to SCSI/SATA/USB drives)

On 7/10/07, Lennart Sorensen <lsorense-1wCw9BSqJbv44Nm34jS7GywD8/FfD2ys at public.gmane.org> wrote:
> On Tue, Jul 10, 2007 at 03:36:25PM -0400, lada-h8kxHjy+vg4AvxtiuMwx3w at public.gmane.org wrote:
> > I migrated my Subversion server from a 800Mhz Pentium 3 with 512 MB of
> > memory to a 3GHz Pentium 4 with 2 GB of memory. They both run Ubuntu 6.06
> > LTS Linux (2.6.15-26-386 kernel).
> > The P4 machine seems to be rather slow. Here is truncated output from top:
> >
> > top - 15:19:19 up 5 days, 22:43,  1 user,  load average: 0.33, 0.09, 0.03
> > Tasks:  56 total,   1 running,  55 sleeping,   0 stopped,   0 zombie
> > Cpu(s):  4.2% us,  0.0% sy,  0.0% ni, 95.8% id,  0.0% wa,  0.0% hi,  0.0% si
> > Mem:   2067576k total,  1474208k used,   593368k free,   213872k buffers
> > Swap:  1951800k total,    18904k used,  1932896k free,  1167500k cached
> >
> >   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
> >
> > 15543 lsvatos   17   0  2196 1088  856 R  3.8  0.1   0:00.53 top
> >
> > And here from the P3 box:
> >
> > top - 15:17:07 up 19 days,  5:09,  1 user,  load average: 0.00, 0.00, 0.00
> > Tasks:  51 total,   1 running,  50 sleeping,   0 stopped,   0 zombie
> > Cpu(s):  0.0% us,  0.3% sy,  0.0% ni, 99.7% id,  0.0% wa,  0.0% hi,  0.0% si
> > Mem:    515284k total,   418848k used,    96436k free,    72740k buffers
> > Swap:   979832k total,    18904k used,   960928k free,   262132k cached
> >
> >   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
> >
> >  9848 lsvatos   16   0  2192 1076  856 R  0.3  0.2   0:00.16 top
> >
> > How is it possible for the same program to consume 10 times the CPU time?
> > I would appreciate any suggestions.
>
> Not having DMA enabled for disk access can cause quite a severe cpu hit.
>
> What does dmesg say on both?
>
> --
> Len Sorensen
> --
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