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2011-02-02
, 04:59
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Posts: 155 |
Thanked: 61 times |
Joined on Nov 2009
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#322
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Originally Posted by craftyguy
The point is that the swap is compressed. Lets say you allow zram0 to be a device that is 128MB (half your ram) and that zram achievs a 50% compression. Without going to physical swap (flash) you now have effectively 128+(128*2) = 384MB ram to work with - yes stuff is going to have to be compressed in and out mean CPU load, but the compression is lite and fast, and if your physical swap is slow, thats still preferable.
I don't get it, why would you use a ramdisk for swap? The whole reason the kernel even uses swap is to take inactive pages out of memory so there is room for active pages. By creating a ramdisk, you reduce the amount of RAM you can use for these active pages. Maybe to reduce wear on the flash device? I think this would ultimately reduce performance since your usable RAM size will be significantly reduced?
It's been a huge win for me on other constrained devices even with faster storage.
For example on a VPS I use:
DiskSize: 524288 kB
OrigDataSize: 104852 kB
ComprDataSize: 36712 kB
MemUsedTotal: 37848 kB
So I've given up 37MB to store 105MB - thats a gain (on a fairly small vps) of 68MB - if the compression stays the same and I use all the allocation - thats approx gain of 300MB on a 1GB system by using 200MB of RAM for the compression. I could be more aggressive too...
I use it on my laptop and desktop as well to great effect.
Last edited by phedders; 2011-02-02 at 05:07.
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2011-02-02
, 10:57
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Posts: 74 |
Thanked: 25 times |
Joined on Jan 2010
@ Hong Kong, CHINA
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#323
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Originally Posted by phedders
I just want to echo the great (qualitative) experience I have had with ramzswap on constrained devices. Given it helps with crappy programs / libraries's memory usage, and the lack of disincentives to fix those, it's almost sure to be beneficial for a long time in the future.
The point is that the swap is compressed.
[...]
It's been a huge win for me on other constrained devices even with faster storage.
Since one is (to oversimplify a tiny bit) trading CPU for RAM, with ~1GHz devices these days only having 256MB of RAM that's usually a win. Even on the OLPC XO-1 with 400MHz CPU and 256MB of RAM it was a win (since the greatest performance optimization is to go from a non-working state to a working state, and yum/rpm are quite memory-hungry at times).
Martin
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2011-02-14
, 13:18
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Posts: 22 |
Thanked: 6 times |
Joined on Dec 2009
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#324
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I'd like to create bridges with the current stable power kernel, however it seems that the bridge module is missing. Is there some way for me to generate this module myself or can anyone supply me with it? Until then, brctl will continue to throw "add bridge failed: Package not installed" my way...
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2011-02-14
, 20:12
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Posts: 10 |
Thanked: 1 time |
Joined on Feb 2011
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#325
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Hi there!
I have installed the sdk-fiasco-gen with dpkg but when I do the "fakeroot apt-get build-dep kernel-power" I got:
Build-Depends dependency for kernel-power cannot be satisfied because the package sdk-fiasco-gen cannot be found
how is it possible???
I have installed the sdk-fiasco-gen with dpkg but when I do the "fakeroot apt-get build-dep kernel-power" I got:
Build-Depends dependency for kernel-power cannot be satisfied because the package sdk-fiasco-gen cannot be found
how is it possible???
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2011-02-14
, 21:16
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Posts: 10 |
Thanked: 1 time |
Joined on Feb 2011
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#326
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I tried also:
cp debian/rx51power_defconfig arch/arm/configs/
make EXTRAVERSION=power46 rx51power_defconfig
make EXTRAVERSION=power46 bzImage
but I got: In file included from arch/arm/mach-omap2/pm.c:37:
arch/arm/plat-omap/include/mach/pm.h:111:2: error: #error "Power management for this processor not implemented yet"
cp debian/rx51power_defconfig arch/arm/configs/
make EXTRAVERSION=power46 rx51power_defconfig
make EXTRAVERSION=power46 bzImage
but I got: In file included from arch/arm/mach-omap2/pm.c:37:
arch/arm/plat-omap/include/mach/pm.h:111:2: error: #error "Power management for this processor not implemented yet"
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2011-02-14
, 22:46
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Posts: 10 |
Thanked: 1 time |
Joined on Feb 2011
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#327
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Originally Posted by Bernard
Hi Bernard,
How do I compile a kernel-power kernel myself?
I followed guides on compiling kernel in scratchbox using information:
http://wiki.maemo.org/Documentation/...o_Kernel_Guide
and
http://www.natisbad.org/N900/n900-custom-kernel.html
the default nokia kernel seems to compile but the power kernel doesn't. As suggested here, I tried the extra step in copying the default config:
http://psfreedom.com/wiki/Nokia_N900...9_maemo_kernel
But when I do "make EXTRAVERSION=.10power46" I stil get an error:Code:cp debian/rx51power_defconfig arch/arm/configs/
If I only compile modules, that seems to work OK, but compiling the entire kernel doesn't work.Code:In file included from arch/arm/mach-omap2/pm.c:37: arch/arm/plat-omap/include/mach/pm.h:111:2: error: #error "Power management for this processor not implemented yet" make[1]: *** [arch/arm/mach-omap2/pm.o] Error 1 make: *** [arch/arm/mach-omap2] Error 2
Can anybody help me?
same problem.
I modified the arch/arm/plat-omap/include/mach/pm.h file commenting the error code message.
It compiles for a while but after I get this other error
LD .tmp_vmlinux1
/scratchbox/compilers/cs2007q3-glibc2.5-arm7/bin/sbox-arm-none-linux-gnueabi-ld: no machine record defined
/scratchbox/compilers/cs2007q3-glibc2.5-arm7/bin/sbox-arm-none-linux-gnueabi-ld: no machine record defined
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2011-02-24
, 15:09
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Posts: 63 |
Thanked: 26 times |
Joined on Jul 2010
@ Canada
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#328
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I'm also failing when I try to rebuild the "stock" power46 kernel with the same "Power management for this processor not implemented yet" error.
I'm trying to include the android-specific patches into the kernel and while it seems to be working with the original kernel from Nokia I would definitely prefer to do the work on the power kernel series...
I'm trying to include the android-specific patches into the kernel and while it seems to be working with the original kernel from Nokia I would definitely prefer to do the work on the power kernel series...
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2011-03-13
, 21:39
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Posts: 74 |
Thanked: 45 times |
Joined on Dec 2010
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#329
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Has anyone evaluate power consumption of kernel?
I mean, I would like to know whether the community kernel has a bigger consumption than former Nokia one or similar?
I mean, I would like to know whether the community kernel has a bigger consumption than former Nokia one or similar?
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2011-03-18
, 08:04
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Posts: 237 |
Thanked: 157 times |
Joined on Dec 2009
@ San Diego, CA
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#330
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Would it be possible for a future build of the power kernel to include the snd_usb_audio module/drivers?
With USB host mode support I'd like to have a go at getting an external mic working with the n900, the mic powers and appears to get sufficient power, but no drivers are present.
With USB host mode support I'd like to have a go at getting an external mic working with the n900, the mic powers and appears to get sufficient power, but no drivers are present.
Can we have the gadgetfs (!= g_file_storage) driver in the next kernel or compiled as a standlone module for power46? This would, among others, allow to simulate a USB keyboard with the N900.
Thanks!
Author of the Advanced Geocaching Tool
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