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Old 12-10-2014, 04:36 PM   #1
bermanor
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poor pcie ssd driver performance on linux 2.6.18(centos 5.7)


Hi all

I have a pcie driver for SSD which reaches a throughput of 3Gbytes/sec when working in centos 6.5(linux 2.6.32).
When I run the same driver under centos 5.7(linux 2.6.18) after performing some minor modifications I can only reach 400Mbytes/sec.

I am using the fio tool on the raw device in order to test performance.The driver uses the blk_queue_make _request function to regiter the bio handling function in order to override the linux elevator.

Can you please tell what could be the reason for the drop in performance?

BR
Oren
 
Old 12-16-2014, 06:24 PM   #2
unSpawn
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Quote:
Originally Posted by bermanor View Post
Can you please tell what could be the reason for the drop in performance?
Do realize CentOS 5 is at 5.11 now so you're lagging behind humonguously. (And 6 is at 6.6) And AFAIK this is not "a drop in performance" but the kind of comparison between kernel versions you shouldn't make IMHO. CentOS 6.5 comes with a much improved kernel versions.
 
Old 12-16-2014, 09:10 PM   #3
John VV
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as above other than you are using UNSUPPORTED versions of 5 and 6

comparing 5 and 6 are like comparing
XP 32 bit NO SERVICE PACK

to win7

apples and oranges
 
Old 12-17-2014, 12:44 AM   #4
Rubian
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What is it with people who refuse to upgrade their OS. Seriously you need to upgrade.
 
  


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