Ian Collins,
My two free cents..
If the gzip was in application space, most gzip's implementations
support (maybe a new compile) a less extensive/expensive "deflation"
that would consume fewer CPU cycles.
Secondly, if the file objects are being written lo
[originally reported for ZFS on FreeBSD but Pawel Jakub Dawid
says this problem also exists on Solaris hence this email.]
Summary: on ZFS, overhead for reading a hole seems far worse
than actual reading from a disk. Small buffers are used to
make this overhead more visible.
I ran the following
A couple more questions here.
[mpstat]
> CPU minf mjf xcal intr ithr csw icsw migr smtx srw syscl usr sys wt idl
> 00 0 3109 3616 316 1965 17 48 45 2450 85 0 15
> 10 0 3127 3797 592 2174 17 63 46 1760 84 0 15
> CPU minf mjf xcal
Roch Bourbonnais wrote:
>
> with recent bits ZFS compression is now handled concurrently with many
> CPUs working on different records.
> So this load will burn more CPUs and acheive it's results
> (compression) faster.
>
Would changing (selecting a smaller) filesystem record size have any effect?
> I'm not quite sure what this test should show ?
For me, the test shows how writing to a gzip compressed
pool completely kills interactive desktop performance.
At least when using an usb keyboard and mouse.
(I've not yet tested with a ps/2 keyboard & mouse; or
a SPARC box)
> Compressing random
[EMAIL PROTECTED] wrote on 05/03/2007 11:35:24 AM:
>
> with recent bits ZFS compression is now handled concurrently with
> many CPUs working on different records.
> So this load will burn more CPUs and acheive it's results
> (compression) faster.
>
> So the observed pauses should be consiste
with recent bits ZFS compression is now handled concurrently with
many CPUs working on different records.
So this load will burn more CPUs and acheive it's results
(compression) faster.
So the observed pauses should be consistent with that of a load
generating high system time.
The assump
I've also noticed brief hangs on my f4k laptop.
build 63 with / on a zfs pool. I was taring up /opt and putting it on a
seperate zfspool.
This second zfspool had compression set to gzip and the machine would
freeze for long periods of time. Setting compression to gzip-9 was
hardest on the ma
On 5/3/07, Frank Hofmann <[EMAIL PROTECTED]> wrote:
I'm not quite sure what this test should show ?
I didn't try the test myself... but I think what it shows is a
possible problem that turning compression can hang a machine.
Rayson
Compressing random data is the perfect way to generate he
I'm not quite sure what this test should show ?
Compressing random data is the perfect way to generate heat.
After all, compression working relies on input entropy being low.
But good random generators are characterized by the opposite - output
entropy being high.
Even a good compressor, if ope
> The reason you are busy computing SHA1 hashes is you are using
> /dev/urandom. The implementation of drv/random uses
> SHA1 for mixing,
> actually strictly speaking it is the swrand provider that does that part.
Ahh, ok.
So, instead of using dd reading from /dev/urandom all the time,
I've no
Jürgen Keil wrote:
A kernel profile seems to show that the kernel is busy with gzip'ing
(and busy with computing SHA1 hashes?):
# lockstat -kIW -D 20 sleep 20
Profiling interrupt: 3882 events in 20.021 seconds (194 events/sec)
Count indv cuml rcnt nsec Hottest CPU+PILCaller
> I just had a quick play with gzip compression on a filesystem and the
> result was the machine grinding to a halt while copying some large
> (.wav) files to it from another filesystem in the same pool.
>
> The system became very unresponsive, taking several seconds to echo
> keystrokes. The box
Ian,
On 5/3/07, Ian Collins <[EMAIL PROTECTED]> wrote:
I don't think it was a maxed CPU problem, only one core was loaded and
the prstat numbers I could get (the reporting period was erratic) didn't
show anything nasty.
Do you have the output of 'mpstat 5'?
--
Just me,
Wire ...
Blog:
__
hello dear community,
Is there a way to have a ``local_name'' as define in iscsitadm.1m when
you shareiscsi a zvol. This way, it will give even easier
way to identify an device through IQN.
Ced.
--
Cedric BRINER
Geneva - Switzerland
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