Develop Bugs

Slow SD card...?

Hi I have a class 10 sd card, and i'm using it for a while now.
When I use the card with the pc the speed is great.
but, I now tested it with the "SD card speed tester" and I got these results:
write: 2 mb/s
read: 3 mb/s
I checked and while there were no apps running from the sd while the test was running.
Can someone explain these results?

Look at this thread for the problem and this for partial solve.

I think its something to do with froyo. On 2.1 i was getting much faster speed than i am now.
This could be down to the fact that task killers dont kill taks properly on froyo and apps are still running in the background.

TheGhost1233 said:
Look at this thread for the problem and this for partial solve.
Click to expand...
Click to collapse
it's amazing thank you very much, i applied the fix and it bumped my read speed from 3 to 15...
I hope Devs will investigate that issue more.. it's a very annoying bug

evo has slow micro sd read speed

I just bought a brand new Patriot 32gb class 10 micro sdhc for my evo 4g. I popped it in to my computer to test the speed with a utility and found that I had a 11mbps write and 14mbps read. Yay! I was happy until I popped it in to my evo and ran a test directly on the phone only to find out that my write speed was the same, but my read speed was stuck at 5mbps no matter how many time I ran it or whether i ran it right after a reboot. I've found a couple of different posts on other forums concerning the matter, and I'm wondering if this is a universal issue for Evo users? The utility I used is call SD Card Speed Tester and it seems to be very accurate. I found a post about desire users at this link http://android.modaco.com/content/h...tch-for-slow-sd-card-read-speed/#entry1475692 and it seems that kernel update fixed the issue for them. Maybe I should present this to a developer. Please let me know if you all are having this issue too.

This may be a function of the cpu, bus, cpu cycle and any no-ops in the os.
There may be a point where it does not make sense to get faster memory. It would be really cool if we could somehow figure out what the optimum SD card performance should be.

I actually found the fix!! It is so simple and I don't understand why all developers aren't integrating it into their roms, it doesn't make sense... All you have to do is use root explorer or some other root file manager and navigate to "/sys/devices/virtual/bdi/179:0/" and open the file "read_ahead_kb" with a text editor (with root explorer just long press the file and select "open with text editor", and if the value is anything other than 4, change it to 128 and save the file. The read speed on my new class 10 card went from 5Mpbs to 15Mbps, BIG DIFFERENCE! Only problem with doing it this way is it changes back to 4 after a reboot. There if a flashable file in the post I got this info from ( http://forum.xda-developers.com/showthread.php?t=815557&page=19 ) but I haven't tried it. Apparently it is very easy to integrate... I'm going to post in the developers section. Enjoy the correct speeds for your card!

Nice
Sent from my PC36100 using XDA App

Sweet. I bet there is something in /etc or an init file.
So your evo is now faster than your computer!

So, what is to stop a person from setting it to 256? Not that anyone really needs to do this, I'm just curious.

Nothing is! 256 and 512 are actually working better for some people. Play around with the values and see what works best for you.

Awesome. I'm testing now. Thanks!

I tried both 256 and 512 and there seems to be no difference. I get read/write scores of around 12MB/s using 128, 256 and 512. I'm guessing that's a limit of the hardware. Is anyone getting better than that?

[Q] SDcard Speed/lag?

When i bought my phone it came with a 8gb class4 sdcard,and worked perfectly and very fast,writing speed was around 5MB/s,after i started moding the phone (root/custom roms/partitioning etc) it slowed down significantly ,writing speed is now down to 1.5~2.5 MB/s , x_X
I have two partitions,ext3 512mb and fat32 the rest....
Any help ?

There are at least 6 threads about this.
It is a partitioning/kernel issue.

Ah,sorry,didnt mean to post it blindly ,but was doing so via TT so didnt have time to browse around.
Links?
EDIT : ok,finally got home and did some browsing
I've looked at some reasons as to the slow writing speed,from the .37 kernel issue to the read_ahead_kb being = 4 and needing a new kernel (as stated in this thread Sense Slow SDcard Fix)...and all were alright on my phone ...

SD Card reading speed fix

Would our phones benefit from this script?
Any brave soul care to try it?
http://forum.xda-developers.com/showthread.php?p=12437265#post12437265

it might be but i think that it uses much ram...

l1q1d said:
it might be but i think that it uses much ram...
Click to expand...
Click to collapse
Iq1d just to clarify a few things If we changed the cache to for example 2048 kb would that mean that the system would have 2MB of ram less? If so we could test other cache sizes for example 1024 that's only a 1 MB of ram and I would be willing to sacriface it for the sake of higher sd writing/reading speeds.
Here's one of the tests from the thread
"My speed test result on HTC Desire CM7 RC2, Kingmax Class 10 8GB
128 default
1) 7.5, 13.5
2) 5.2, 16.2
3) 18.6, 18.7
4) 18.8, 20.9
4096
26.2, 53.9
17.5, 62.9
19.7, 59.6
26.7, 57.2
27.8, 55.7
3072 - before reboot
23.6, 46.7
17.6, 70.2
24.3, 36.5
23.6, 66.1
15.9, 67.2
3072 - after reboot
6.2, 51.6
13.5, 23.3
5.4, 17.4
11.5, 86.4
16.7, 41.6
25, 50.9
23.6, 51.7
I think it is worth trying I suppose it would speed up the devices of users who have data on sd card.

To gain extreme stability, we must use data on sd img/part.
If we can improve sd reading speed at the cost of 1/2 mb of ram, it would be worth it IMHO.

i really hope this works, as the only way to have stable data is on SD but the phone runs really really slow this way.
EDIT: I installed SD tools and ran it a couple of times, getting speeds of around 5mbps write/ 10mbps read on my class2. With these speeds my kaiser runs painfully slowly, wondering if the script will make any noticable difference.

Aiex Rlder said:
i really hope this works, as the only way to have stable data is on SD but the phone runs really really slow this way.
EDIT: I installed SD tools and ran it a couple of times, getting speeds of around 5mbps write/ 10mbps read on my class2. With these speeds my kaiser runs painfully slowly, wondering if the script will make any noticable difference.
Click to expand...
Click to collapse
Results from one of the users from the thread.
Using the 2gb Class 2 that came with the phone.
Default:
W: 4.2
R: 9.3
2048kb:
W: 4
R: 26.2
3024kb:
W: 5.1
R: 33.8
The card read speed gains are mind blowing.

-Arturo- said:
Results from one of the users from the thread.
Using the 2gb Class 2 that came with the phone.
Default:
W: 4.2
R: 9.3
2048kb:
W: 4
R: 26.2
3024kb:
W: 5.1
R: 33.8
The card read speed gains are mind blowing.
Click to expand...
Click to collapse
are you using data on SD? does your kaiser feel faster? because i don't know if i've done it wrong but my system is really slow all the time and apps are even slow

Aiex Rlder said:
are you using data on SD? does your kaiser feel faster? because i don't know if i've done it wrong but my system is really slow all the time and apps are even slow
Click to expand...
Click to collapse
You misunderstood me. This arent my results I just posted them here. The resulrs where taken from the original sd card fix thread.

-Arturo- said:
You misunderstood me. This arent my results I just posted them here. The resulrs where taken from the original sd card fix thread.
Click to expand...
Click to collapse
ah sorry must learn to read <_<

-Arturo- said:
Would our phones benefit from this script?
Any brave soul care to try it?
http://forum.xda-developers.com/showthread.php?p=12437265#post12437265
Click to expand...
Click to collapse
Hm, could be useful for people who have fried NANDs ... *cough*
Though what really needs to improve is write speeds. Read speeds would be fine if /system is on NAND, but write speeds needs to improve as that's where our slowdowns come from.
On average, our Kaiser's SD Card reader writes on average 4.8Mbps, where it writes about 8-12Mbps depending on how much actual RAM is available.
Granted we could really use the increase in read speeds, but what good is fast read speeds if the SD card dogs down due to it having a very slow write speed.

ok, OC 480, data on sd partition. micro sdhc 4gb CLASS 2. Custom rom based on Gingerbones.
2048:
Write- 5.7
Read- 23.4
128(default):
Write- 5.7
Read- 12.1
4096: (OC 550)
Write- 6.1
Read- 11.5

hmm i tested this by just manual editing the value which resets after reboot.
4gb class2 card with no OC. sys on nand, data in partition using not so super froyo.
128:
write: 4.8 read 11.4
2048:
write 5.2 read 24.2
not sure if this improvement in read speed actually speeds up my kaiser. do you think a class 6 card would speed it up much?
not sure exactly how to implement it permanently, i tried manually adding a file but it didn't seem to work. though altering this value isn't too bad as i don't reboot often.

There's no caching on write aparently (probably to avoid lost data).
So writes must be mostly dependent on class + SD reader/writer driver.
Acording to wikipedia:
Class 2, 2 MB/s, slowest for SDHC cards.
Class 4, 4 MB/s.
Class 6, 6 MB/s.
Class 10, 10 MB/s.
(this is write speed, MegaBYTE).
So... either we are getting bogus results, or our cards are a little above the quoted class.

daedric said:
There's no caching on write aparently (probably to avoid lost data).
So writes must be mostly dependent on class + SD reader/writer driver.
Acording to wikipedia:
Class 2, 2 MB/s, slowest for SDHC cards.
Class 4, 4 MB/s.
Class 6, 6 MB/s.
Class 10, 10 MB/s.
(this is write speed, MegaBYTE).
So... either we are getting bogus results, or our cards are a little above the quoted class.
Click to expand...
Click to collapse
i think the classes are minimum speeds, and it seems other users are getting higher speeds than their class. how did you implement this script btw?

Read 1st post. Follow Link. Read whole 1st post there. There's a sample script there.
You must create a file in /system/etc/init.d/ named 99something_you_chose (should begin with 99, the files are executed in order, we should have our script run last).
So... either you remount /system with read+write permissions, and put the file there, or edit the androidinstall.tar and put the file there, or a androidupdate.tar with the file there.
Or...
https://market.android.com/details?id=com.vaelek.sdspeedboost

daedric said:
Read 1st post. Follow Link. Read whole 1st post there. There's a sample script there.
You must create a file in /system/etc/init.d/ named 99something_you_chose (should begin with 99, the files are executed in order, we should have our script run last).
So... either you remount /system with read+write permissions, and put the file there, or edit the androidinstall.tar and put the file there, or a androidupdate.tar with the file there.
Or...
https://market.android.com/details?id=com.vaelek.sdspeedboost
Click to expand...
Click to collapse
@Daiedric
Did you notice any speed improvements in data read?

Wow, class 2 4GB sdhc /system on ext4 /data on ext4, Krazy 2.6.32.9, cynMod7,
Rogue Tools OC 529
Before
write 1.8
read 9.1
After mod to 2048 with Root explorer
write 2.9
read 20.1

hmm, drfno1, so do you have system and data on your SD card? is your kaiser quite slow then with write speeds of 2MBbps :S
i can't decide whether to buy a higher class SD card and if that will improve my kaiser's speed.

Been playing with this config only a few days with wifi only. My understanding is that the ext4 file system speed is what makes the system very usable. The only thing I find frustrating is the time it takes to boot and become stable. I say try it on your current sd first. The boost in reading seems to help starting apps and using file managers.

drfno1 said:
Been playing with this config only a few days with wifi only. My understanding is that the ext4 file system speed is what makes the system very usable. The only thing I find frustrating is the time it takes to boot and become stable. I say try it on your current sd first. The boost in reading seems to help starting apps and using file managers.
Click to expand...
Click to collapse
I don't like this sd tools app at all. It gives me some ridiculous readings. I have a 6 gig class 4 card with 5 GB fat32 partition, the app shows that the size of the partition is 4,2 gb. Also I get speeds of around 1.9 writing and 4.5 reading...this can't be right. I have just tried another app and the results were as follows writing speed 5.1 and reading speed 10, this seems more like it. Unfortunately after applying the script I don't see any changes in results still around 5ws /10 rs.

[Q] SD Card Speed Booster - Is it working for you?

There is an app called SD Card Speed Booster in the Market.
Is it working for you?
I got it from 128 to 4096.
Maybe the gallery is a little quicker...

Have you tried this mod yet?
http://forum.xda-developers.com/showthread.php?t=1010807
It showed a little improvement for me. Run the benchmark program "SD Tools" to get your before and after.

Yup,big improvement. Flashed this morning & now my pic gallery loads almost instantly.
Sent from my HTC Vision using XDA Premium App

Both of those methods do the exact same thing - one just takes no memory to do. All they do it set the read ahead buffer to a higher limit. Next time you open something from the sdcard - odds are it's still in the memory so it loads from there without needing to wait for the sdcard. It *should* work for a2ext also so if you have a slow card (or even a fast one) things will become faster. Not sure if it helps with linux swap though (not that we really need it) - will some one with swap test this to confirm?

Okay I installed SD tools and this is what came out:
before.
write speed: 7.7 mb/s
read speed: 17.5 mb/s
after.
write speed: 8.8 mb/s
read speed: 17.5 mb/s
So only the write speed improved...