Originally posted by cyring
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Linux I/O Scheduler Comparison On The Linux 3.4 Desktop
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What I'm curious about is some watt/power use comparison benchmarks.
I've been using deadline on my laptop for a while, as I've noticed less power use. TBH, I don't know if it actually gives me better battery life or it's just me thinking it does.
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Originally posted by Sadako View PostI've never heard this before, any links or references?
http://en.wikipedia.org/wiki/Noop_scheduler
http://grzen.blogspot.fr/2009/05/ssd...-linux_18.html
http://ubuntuforums.org/showthread.php?t=1178209
According to Wikipedia :- " NOOP scheduler is best used with solid state devices such as flash memory or in general with devices that do not depend on mechanical movement ... "
- Deadline: " The kernel documentation suggest this is the preferred scheduler for database systems ... "
In Kernel doc /usr/src/linux/Documentation/block/cfq-iosched.txt says :
" That means by default we idle on queues/service trees. This can be very helpful on highly seeky media like single spindle SATA/SAS disks ... "
I'm looking for a way to specify the kernel which respective scheduler to use with SSD & HDD, using boot command such as : elevator-DEVICE=<scheduler> rather than dealing with /sys/block/DEVICE/queue/scheduler (which happens after boot, ie. rc.local)
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Originally posted by cyring View PostBellow, some of my readings
http://en.wikipedia.org/wiki/Noop_scheduler
http://grzen.blogspot.fr/2009/05/ssd...-linux_18.html
http://ubuntuforums.org/showthread.php?t=1178209
According to Wikipedia :- " NOOP scheduler is best used with solid state devices such as flash memory or in general with devices that do not depend on mechanical movement ... "
- Deadline: " The kernel documentation suggest this is the preferred scheduler for database systems ... "
In Kernel doc /usr/src/linux/Documentation/block/cfq-iosched.txt says :
" That means by default we idle on queues/service trees. This can be very helpful on highly seeky media like single spindle SATA/SAS disks ... "
I'm looking for a way to specify the kernel which respective scheduler to use with SSD & HDD, using boot command such as : elevator-DEVICE=<scheduler> rather than dealing with /sys/block/DEVICE/queue/scheduler (which happens after boot, ie. rc.local)
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Originally posted by Hirager View PostThank you for this one. I also would like to know how to specify the scheduler at boot time. I don't want to recompile the whole kernel just to set other scheduler as default.
In my Wiki, I post my Syslinux boot config file, check line #47
If you are using Grub, it looks like this in the /boot/grub/menu.lst file
Code:title Arch Linux kernel /boot/vmlinuz-linux root=/dev/sdb2 ro vga=0xf01 rootdelay=0 quiet nomodeset [COLOR="#0000FF"]elevator=deadline[/COLOR] nmi_watchdog=0 initrd /boot/initramfs-linux.img
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Originally posted by Mystro256 View PostWhat I'm curious about is some watt/power use comparison benchmarks.
I've been using deadline on my laptop for a while, as I've noticed less power use. TBH, I don't know if it actually gives me better battery life or it's just me thinking it does.
http://en.wikipedia.org/wiki/PowerTOP
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Originally posted by disi View PostI have one in my Laptop and if I copy a ~20GB file, I cannot watch a video next to it. It will hang for 3-4 seconds. (Fedora 17)
Not really sure if I got it correctly aligned though, we really need a simple tool for that doesn't use these legacy cylinders and sector sizes and a consistent terminology to describe SSDs...
Code:% sudo parted /dev/sda --list Passwort: Modell: ATA SanDisk SDSSDX24 (scsi) Festplatte /dev/sda: 240GB Sektorgr??e (logisch/physisch): 512B/512B Partitionstabelle: msdos Disk Flags: Nummer Anfang Ende Gr??e Typ Dateisystem Flags 1 1049kB 215GB 215GB primary ext4 boot % dd if=/dev/zero of=zero.txt bs=50M count=20 20+0 Datens?tze ein 20+0 Datens?tze aus 1048576000 Bytes (1,0 GB) kopiert, 2,72858 s, 384 MB/s % dd if=zero.txt of=zero2.txt bs=50M count=20 20+0 Datens?tze ein 20+0 Datens?tze aus 1048576000 Bytes (1,0 GB) kopiert, 2,80263 s, 374 MB/s
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If "Anfang" means first sector of partition ? 2049kB seems not aligned as not being a multiple of 512 (physical sector size)
One easy way is to partition with Windows Seven startup DVD which cares about SSD then back during Linux installation, change part type to Ext FS
However both fdisk and parted are today ready for SSD presenting the sector way rather than CHS
Originally posted by ChrisXY View Post...
Not really sure if I got it correctly aligned though, ...
Code:% sudo parted /dev/sda --list Passwort: Modell: ATA SanDisk SDSSDX24 (scsi) Festplatte /dev/sda: 240GB Sektorgr??e (logisch/physisch): 512B/512B Partitionstabelle: msdos Disk Flags: Nummer Anfang Ende Gr??e Typ Dateisystem Flags 1 1049kB 215GB 215GB primary ext4 boot % dd if=/dev/zero of=zero.txt bs=50M count=20 20+0 Datens?tze ein 20+0 Datens?tze aus 1048576000 Bytes (1,0 GB) kopiert, 2,72858 s, 384 MB/s % dd if=zero.txt of=zero2.txt bs=50M count=20 20+0 Datens?tze ein 20+0 Datens?tze aus 1048576000 Bytes (1,0 GB) kopiert, 2,80263 s, 374 MB/s
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Originally posted by cyring View PostIf "Anfang" means first sector of partition ? 2049kB seems not aligned as not being a multiple of 512 (physical sector size)
One easy way is to partition with Windows Seven startup DVD which cares about SSD then back during Linux installation, change part type to Ext FS
However both fdisk and parted are today ready for SSD presenting the sector way rather than CHS
Would resizing the beginning of the partition to the correct "sector" be the right thing to do or do I have to recreate the whole partition (and/or table)?
Right, english is better:
Code:~ % sudo LC_ALL=C fdisk -u -l /dev/sda Disk /dev/sda: 240.1 GB, 240057409536 bytes 64 heads, 32 sectors/track, 228936 cylinders, total 468862128 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x1d172924 Device Boot Start End Blocks Id System /dev/sda1 * 2048 419432447 209715200 83 Linux % sudo LC_ALL=C parted --list Model: ATA SanDisk SDSSDX24 (scsi) Disk /dev/sda: 240GB Sector size (logical/physical): 512B/512B Partition Table: msdos Disk Flags: Number Start End Size Type File system Flags 1 1049kB 215GB 215GB primary ext4 boot
Hopefully 1049kB (not 2049) is actually 512 kbyte * 2.
But it doesn't matter that much since I don't have too much bandwidth on this notebook anyway (will get replaced in the not so far future):
Code:% sudo LC_ALL=C hdparm -t /dev/sda /dev/sda: Timing buffered disk reads: 776 MB in 3.00 seconds = 258.59 MB/sec
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Originally posted by cyring View PostBellow, some of my readings
http://en.wikipedia.org/wiki/Noop_scheduler
http://grzen.blogspot.fr/2009/05/ssd...-linux_18.html
http://ubuntuforums.org/showthread.php?t=1178209
According to Wikipedia :- " NOOP scheduler is best used with solid state devices such as flash memory or in general with devices that do not depend on mechanical movement ... "
- Deadline: " The kernel documentation suggest this is the preferred scheduler for database systems ... "
In Kernel doc /usr/src/linux/Documentation/block/cfq-iosched.txt says :
" That means by default we idle on queues/service trees. This can be very helpful on highly seeky media like single spindle SATA/SAS disks ... "
I'm looking for a way to specify the kernel which respective scheduler to use with SSD & HDD, using boot command such as : elevator-DEVICE=<scheduler> rather than dealing with /sys/block/DEVICE/queue/scheduler (which happens after boot, ie. rc.local)
Don't have any links for this though, but it does kind of make sense to me...
Also, somewhat off topic, but I'm adding an SSD to my desktop and considering putting the journal for the SSD's ext4 filesystem on a partition at the very start of a hard disk in the system, should reduce writes somewhat, with hopefully not much of a performance impact, any thoughts?
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