<div dir="ltr">Hi,<br><br>I would try to focus on the I/O issue. (best guess I have so far)<br>Some things I would check:<br>1. file system cache. mayeb the file is already in cache? maybe all memory is allocated and no free ram for cache? etc.<br>
2. dmesg and/or /var/log/messages -> check if there are weird I/O errors. (same for raid controller if any)<br>3. iostat / sar. check the disk performance. see the numbers, especially throughput, service time & average wait looks reasonable.<br>
<br><br><div class="gmail_quote">On Tue, Sep 8, 2009 at 3:30 PM, Noam Rathaus <span dir="ltr"><<a href="mailto:noamr@beyondsecurity.com">noamr@beyondsecurity.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div dir="ltr">Hi Noam,<br><br>Yes I looked with strace.<br><br>The most notable difference is the read time on files (new HD)<br>0.047210 read(7, " <= 0)\n {\n $numLimit = 10;\n }\n\n "..., 4096)<br><br>Instead of (old HW)<br>
0.001462 read(6, "owItem = $1;\n\n my $RowItems = $s"..., 4096) = 4096<br><br>That is 40 times slower (it is the same file being opened)<br><br>I have no idea why there is such a difference<br><br>hdparm on the old:<br>
hdparm -t /dev/sda<br><br>/dev/sda:<br> Timing buffered disk reads: 190 MB in 3.02 seconds = 62.87 MB/sec<br><br>hdparm on the new:<br># hdparm -t /dev/sda<br><br>/dev/sda:<br> Timing buffered disk reads: 314 MB in 3.01 seconds = 104.22 MB/sec<div>
<div></div><div class="h5"><br>
<br><div class="gmail_quote">On Tue, Sep 8, 2009 at 3:02 PM, Noam Meltzer <span dir="ltr"><<a href="mailto:tsnoam@gmail.com" target="_blank">tsnoam@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div dir="ltr">Did you try to check with strace ?<br><br><div class="gmail_quote">2009/9/8 Noam Rathaus <span dir="ltr"><<a href="mailto:noamr@beyondsecurity.com" target="_blank">noamr@beyondsecurity.com</a>></span><br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div><div></div><div>
<div dir="ltr">Hi,<br><br>I have two machines, their hardware is not identical, but their installation is.<br><br>One is a 3 years old DELL server, while the other is a 1 year old server.<br><br>One is running 2.6.26-2-686 while the other 2.6.30-1-686<br>
<br>What I am seeing is slow startup - emphasis on startup, the code works fast once its running - of perl scripts<br><br>Even the smallest perl script such as this:<br>===<br>#!/usr/bin/perl<br><br>use lib '/usr/local/MySystem/lib';<br>
<br>use DB;<br><br>===<br><br>Take 7 seconds to start, in comparison to 0.030secods<br><br>If I don't use the "use DB;" which my package<br><br>It loads fast<br><br>I am trying to figure out why, I checked the HD speeds via hdparam, the newer server is 1.5 times faster 103MB/sec<br>
<br>I tried to see what libraries were being used, used strace, but I can't see something "big" that is causing the delay.<br><br>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<br>
<br>Does someone have a "thread" to cling to?<br><br>Thanks,<br>Noam Rathaus<br></div>
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