New Reiser4 snapshot slower?

New Reiser4 snapshot slower?

[Jonathan Briggs]

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This command:
# dd if=/dev/zero of=testfile bs=4k count=256k
seems to take longer than it did before.  The difference seems to be all
system time.

I will have to reboot to an old version later, to get accurate numbers.

I don't have debugging turned on, so that's not it.  Has something
changed that would have made this slower?
-- 
Jonathan Briggs
jbriggs@esoft.com

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Re: New Reiser4 snapshot slower?

[Hans Reiser]

Jonathan Briggs wrote:

>This command:
># dd if=/dev/zero of=testfile bs=4k count=256k
>seems to take longer than it did before.  The difference seems to be all
>system time.
>
>I will have to reboot to an old version later, to get accurate numbers.
>
>I don't have debugging turned on, so that's not it.  Has something
>changed that would have made this slower?
>  
>
zam, please look into this report.

-- 
Hans

Re: New Reiser4 snapshot slower?

[Jonathan Briggs]

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On Fri, 2004-03-26 at 14:00, Jonathan Briggs wrote:
> This command:
> # dd if=/dev/zero of=testfile bs=4k count=256k
> seems to take longer than it did before.  The difference seems to be all
> system time.
> 
> I will have to reboot to an old version later, to get accurate numbers.
> 
> I don't have debugging turned on, so that's not it.  Has something
> changed that would have made this slower?

I have some numbers for the previous snapshot vs the current
snapshot.  It doesn't look like there was much of a difference really. 
The real difference seems to be between a empty filesystem and one
that's been used as a home directory for several months.  That's where
my impression of slowness comes from: the last time I speed tested it,
my home directory was empty.

In /home:
With new R4 snapshot:
1 GB from /dev/zero into testfile
real: 38.301 s
system: 6.508 s
 
With old snapshot:
1 GB
real: 33 s
sys: 6.9 s
 
In fresh built R4 filesystem on loopback
Old snapshot
real: 24.2
system: 6.7
 
New snapshot
real: 22.7
system: 6.5

I also booted the new snapshot with profile=2 and created a 1 GB
testfile in my home directory and sorted the output of readprofile. 
Here are the interesting bits of that:
   132 handle_IRQ_event                           1.1786
    51 jnode_set_type                             1.5938
   175 clear_user                                 2.1875
  2311 protect_extent_nodes                       2.5340
  1060 do_softirq                                 6.6250
  1114 protect_reloc_node                        13.9250
  3503 __copy_from_user_ll                       27.3672
  8710 unprotect_extent_nodes                    45.3646
 12285 jlookup                                   54.8438
 33297 default_idle                             693.6875

-- 
Jonathan Briggs
jbriggs@esoft.com

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Re: New Reiser4 snapshot slower?

[Hans Reiser]

The repacker should help when it is ready.

-- 
Hans