What does noop, deadline and cfq mean?
Ben36 said:
What does noop, deadline and cfq mean?
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They are different kinds of schedulers of the linux kernel.
en.wikipedia.org/wiki/Noop_scheduler
en.wikipedia.org/wiki/Deadline_scheduler
en.wikipedia.org/wiki/CFQ
Sorry, can't link for now :/
deadline is more power aware and stable, noop has lower latency and performance at the loss of stability, so you may see excessive power usage and occasional miswrites to l1 cache
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I've already read that the different schedulers really only provide a marginal performance benefit, but I'm still curious. The main ones I always see with kernels in Voltage Control are NOOP, Deadline, CFQ, SIO, & BFQ. What are the differences between them? I can never really find a full answer/explanation.
NoHolidaysForAHooker said:
I've already read that the different schedulers really only provide a marginal performance benefit, but I'm still curious. The main ones I always see with kernels in Voltage Control are NOOP, Deadline, CFQ, SIO, & BFQ. What are the differences between them? I can never really find a full answer/explanation.
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There are 2 primary performance parameters for schedulers - Throughput and Latency. The differences typically are less than 5%, but it is sufficient to cause fully functional scheduler or not properly functional scheduler (missed calls, lost data...).
The simpler schedulers tended toward throughput, the more complicated schedulers tended toward latency (simple hardware only need simple NOOP version, complex hardware required complicated schedulers from the myriads of diverse tasks and I/O events).
Throughput <- NOOP <- SIO <- Deadline -> CFQ -> BFQ -> Latency.
thanks man, i've read all of that but in bits and pieces so it's great to get it at once to make sense of it. that little spectrum between focusing on throughput vs latency was helpful
NoHolidaysForAHooker said:
thanks man, i've read all of that but in bits and pieces so it's great to get it at once to make sense of it. that little spectrum between focusing on throughput vs latency was helpful
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It's definitely can be confusing when only in bits and pieces, in large complex systems the I/O schedulers and task schedulers often are intergrated in to one as they share and overlap (scheduler's job is bandwidth distribution).
Schedulers are chosen not directly by performance but by optimal capacity of simultaneous handling events, for example....
NOOP - 2 or less
SIO - 4 or less
Deadline - 8 or less
CFQ - 16 or less
BFQ - greater than 16
guys simple question that needs and answer , what are the best I/O scheduler and Governor in terms of raw speed performance ?
i'm using night-elf kernel v8.5 and this kernel have plenty of them....
Personally I use I/O SIO, by far the fastest. And if you want a good battery and performance use lagfree.
Ondemand as also good values in performance.
Theres a thread that explains you all the schedulers and governors.
For benchmark use sio and performance governor. Just for the show.
The link to the trhead.
http://forum.xda-developers.com/showthread.php?t=1443731
Regards.
ok i'm finally set for I/O = SIO , Governor = smartassV2
the UI feels so much more smoother than before , my default was noob and ondemand
Hey Everyone, i wanted to see if anyone changed their i/o scheduler on the stock rom.
I am using NOOP still.... i tried Deadline and CFQ (deadline supposedly gives system reads higher priority)
My benchmarks are quite sporadic... looking to see if you guys changed this yet.
As title says, what is the best setting to be chosen?kindly brief the detail coz im newbie
Sent from my SK17i using XDA
Well it depends on taste and kernel support but for me the best will be interactivex as governor and sio as I/o scheduler, it gives you no lags and good battery life.
i installed x kernel v4, did not have to change the cpu governor or i/o.
i only install nofrills to do benchmark, then removed it afterwards.
best battery life ever on hybrom v16
i think it uses ondemand for cpu, not sure wether it uses noop or deadline for i/o
i am currently testing smartassV2 cpu governor with simple i/o scheduler on krsh3 kernel
so far battery time is better with these settings than the default ondemand governor
http://forum.xda-developers.com/showthread.php?t=1369817
what is the best GPU governor and I/O for S3 ?
and i use foxhound 1.4
thank you
Hi,
You mean CPU governor, right?
Pegasusq for the governor, optimized for quad core processors and for the I/O scheduler I would say Deadline or Noop.
You can read this about I/O shedulers: http://forum.xda-developers.com/showpost.php?p=22134559&postcount=4 or http://forum.xda-developers.com/showpost.php?p=23885668&postcount=1
Ant it depends also of the kernel for the I/O scheduler, some kernels don't have all the I/O schedulers described above.
viking37 said:
Hi,
You mean CPU governor, right?
Pegasusq for the governor, optimized for quad core processors and for the I/O scheduler I would say Deadline or Noop.
You can read this about I/O shedulers: http://forum.xda-developers.com/showpost.php?p=22134559&postcount=4 or http://forum.xda-developers.com/showpost.php?p=23885668&postcount=1
Ant it depends also of the kernel for the I/O scheduler, some kernels don't have all the I/O schedulers described above.
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OH I mean CPU ^^
thank you