Perl slowness

[Noam Rathaus]

Hi Noam,

Yes I looked with strace.

The most notable difference is the read time on files (new HD)
0.047210 read(7, " <= 0)\n {\n  $numLimit = 10;\n }\n\n "..., 4096)

Instead of (old HW)
0.001462 read(6, "owItem = $1;\n\n my $RowItems = $s"..., 4096) = 4096

That is 40 times slower (it is the same file being opened)

I have no idea why there is such a difference

hdparm on the old:
hdparm -t /dev/sda

/dev/sda:
 Timing buffered disk reads:  190 MB in  3.02 seconds =  62.87 MB/sec

hdparm on the new:
# hdparm -t /dev/sda

/dev/sda:
 Timing buffered disk reads:  314 MB in  3.01 seconds = 104.22 MB/sec

On Tue, Sep 8, 2009 at 3:02 PM, Noam Meltzer <tsnoam at gmail.com> wrote:

> Did you try to check with strace ?
>
> 2009/9/8 Noam Rathaus <noamr at beyondsecurity.com>
>
>> Hi,
>>
>> I have two machines, their hardware is not identical, but their
>> installation is.
>>
>> One is a 3 years old DELL server, while the other is a 1 year old server.
>>
>> One is running 2.6.26-2-686 while the other 2.6.30-1-686
>>
>> What I am seeing is slow startup - emphasis on startup, the code works
>> fast once its running - of perl scripts
>>
>> Even the smallest perl script such as this:
>> ===
>> #!/usr/bin/perl
>>
>> use lib '/usr/local/MySystem/lib';
>>
>> use DB;
>>
>> ===
>>
>> Take 7 seconds to start, in comparison to 0.030secods
>>
>> If I don't use the "use DB;" which my package
>>
>> It loads fast
>>
>> I am trying to figure out why, I checked the HD speeds via hdparam, the
>> newer server is 1.5 times faster 103MB/sec
>>
>> I tried to see what libraries were being used, used strace, but I can't
>> see something "big" that is causing the delay.
>>
>> The "use DB;" can be replaced with any other "custom" library package I
>> wrote, they all take 2-7 seconds to load, while on the other machine it
>> takes negligible time
>>
>> Does someone have a "thread" to cling to?
>>
>> Thanks,
>> Noam Rathaus
>>
>> _______________________________________________
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>> Linux-il at cs.huji.ac.il
>> http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
>>
>>
>
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