Arch Linux

mzneverdies

Member

Registered: 2012-02-04

Posts: 147

[SOLVED] Noop I/O Scheduler

Hello
Recently I bought a SSD drive, which is now my main drive. I'm reading and reading about how to tun it to get the best performance, and the archwiki says:

I/O Scheduler
Consider switching from the default CFQ scheduler (Completely Fair Queuing) since 2.6.18 to NOOP or Deadline. The latter two offer performance boosts for SSDs. The NOOP scheduler, for example, implements a simple queue for all incoming I/O requests, without re-ordering and grouping the ones that are physically closer on the disk. On SSDs seek times are identical for all sectors, thus invalidating the need to re-order I/O queues based on them.

How can I check which scheduler am I using, and how can I change it?

Thanks!

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EDIT
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Ok, my fault, I stopped reading just before the awnser!

Using the sys virtual filesystem (for multiple devices)
This method is preferred when the system has several physical storage devices (for example an SSD and an HDD). Add the following line in /etc/rc.local:
echo noop > /sys/block/sdX/queue/scheduler
where X is the letter for the SSD device.

Last edited by mzneverdies (2012-09-07 10:22:21)

WorMzy

Administrator

From: Scotland

Registered: 2010-06-16

Posts: 13,521

Website

Re: [SOLVED] Noop I/O Scheduler

https://wiki.archlinux.org/index.php/SS … _Scheduler

Read more than just the intro.

Last edited by WorMzy (2012-09-07 10:22:50)

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Earnestly

Member

Registered: 2011-08-18

Posts: 805

Re: [SOLVED] Noop I/O Scheduler

echo noop > /sys/block/sdX/queue/scheduler

Or better, use udev rules to check for rotational media.

#'deadline' is recommended by the author of CFQ for SSDs, replace it with 'noop' if you want.
ACTION=="add|change", KERNEL=="sd[a-z]", ATTR{queue/rotational}=="0", ATTR{queue/scheduler}="deadline"

Last edited by Earnestly (2012-09-07 12:11:20)

mzneverdies

Member

Registered: 2012-02-04

Posts: 147

Re: [SOLVED] Noop I/O Scheduler

Thanks!
I did used the udev rules instead

now, my ssd is running deadline (changed my mind in the last senconds, from noop to deadline)

[mz@gantz ~]$  cat /sys/block/sda/queue/scheduler
noop [deadline] cfq