Fix for slow SD card speed with HTC's Froyo Kernel

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There have been quite a few complaints about slow SD card speeds with Froyo/Sense ROMs (e.g. http://forum.xda-developers.com/showthread.php?t=778748).

I've looked into the problem and discovered that the poor performance is due to HTC reducing the readahead settings in their kernel.

I've attached a prebuilt kernel (as a flashable zip using Koush's AnyKernel) and a kernel source patch that fix this. Let me know how you get on

EDIT: if you prefer Richardtrip's kernel to the stock one, use the update zip here, or v5 or later of his kernel, instead of kernel_2.6.32-frankoid.zip

To see whether your kernel needs the fix you need to run a command with your phone plugged in to your computer. On Linux and OS X you need to include quotes, like this:

adb shell 'cat /sys/devices/virtual/bdi/179:0/read_ahead_kb'

If you are using Windows don't include the quotes - run this:

adb shell cat /sys/devices/virtual/bdi/179:0/read_ahead_kb

If it returns 4 then you need the fix. If it returns 128 you don't need it.

If you are a developer and you'd like to incorporate this fix into your ROM without having to change the kernel see this post for instructions on how to edit init.rc to change the readahead setting.

only for SENCE

Originally Posted by hensk

only for SENCE

Yes, this is only for Sense, but I haven't had any problem with SD card speeds on non-Sense ROMs.

Will flashing this remove OC? I'm running Richards kernel and not stock. Will your zip file overwrite?

Sent from my HTC Desire

Originally Posted by elmalote

Will flashing this remove OC? I'm running Richards kernel and not stock. Will your zip file overwrite?

I'm not sure, I don't overclock myself. I have turned off perflock in this kernel though so it might work.

You could always give it a try and restore a nandroid backup if you lose OC.

The best thing in the long run would probably be to ask Richard to apply the patch to his kernel.

Don't works on rcmixhd v10. I flash it and not reboot well

Sent from my HTC Desire using Tapatalk

Originally Posted by elmalote

Will flashing this remove OC? I'm running Richards kernel and not stock. Will your zip file overwrite?

Sent from my HTC Desire

Want to know this as well, but if you've fixed the problem my hat off to you sir! It really annoys me.

Nice, gonna check it out. Do you have any statistics?

*edit, this has already been pushed upstream to .35+ kernels.

Not working in RcmixHD..!!!

In which ROM did you try OP..??

Originally Posted by harish.awe

Not working in RcmixHD..!!!

In which ROM did you try OP..??

RCmixHD is the rom port from the desire HD isn't it?