How to measure the RAM read/write performance
sandeep kumar
coolsandyforyou at gmail.com
Sat Mar 2 01:51:40 EST 2013
>Another easy way to make memory(ie..pages) non cacheble is use the
>below function,
>dma_alloc_coherent(NULL, size, &p, GFP_KERNEL);
I did like what you said. With the timings,i can see it is reading directly
from RAM. I have some doubts..
--> What exactly happend here? Here read/write are done by CPU or DMA
controller?
I am new to DMA kind of operations, i have one doubt in how to do DMA?
Can you give me some example driver code, for this following case....
--> I want to do a DMA from a mem mapped I/O (lets say physical 0x40000000)
to RAM location @ 0x80000000.
How do you do this?
Thanks
Sandeep
On Fri, Mar 1, 2013 at 10:45 AM, Arun KS <getarunks at gmail.com> wrote:
> On Thu, Feb 28, 2013 at 3:54 PM, sandeep kumar
> <coolsandyforyou at gmail.com> wrote:
> >>1. use early_param to get the physical start address and size of
> >> test_region, or you can just ignore this step and hard code to 510M and
> 2M
> >> for test purpose only.
> >
> >>2. use ioremap_nocache() to map this region to a virtual region. note
> that
> >> this funtion may fail if you are asking a very large vitual memroy
> region.
> > I did the following things,
> >
> > Thank you so much...It worked. With this i am able to measure RAM
> > performance.
>
> Another easy way to make memory(ie..pages) non cacheble is use the
> below function,
> dma_alloc_coherent(NULL, size, &p, GFP_KERNEL);
>
> This will set the page tables attributes for this page no-cachable.
> All reads & writes will always happen from main memory because MMU see
> the memory attribute for this page as non cacheble.
>
> Thanks,
> Arun
> >
> >
> > On Thu, Feb 28, 2013 at 11:39 AM, sandeep kumar <
> coolsandyforyou at gmail.com>
> > wrote:
> >>
> >> >1. use early_param to get the physical start address and size of
> >> > test_region, or you can just ignore this step and hard code to 510M
> and 2M
> >> > for test purpose only.
> >>
> >> >2. use ioremap_nocache() to map this region to a virtual region. note
> >> > that this funtion may fail if you are asking a very large vitual
> memroy
> >> > region.
> >> I did the following things,
> >> 1) Reserved 3MB memory through ATAGS
> >> 2) Wrote small driver to ioremap that memory in following way,
> >>
> >> void *tcpm_base = ioremap_nocache(0x03B00000, SZ_3MB);
> >> 27 if(tcpm_base!=NULL)
> >> 28 {
> >> 29 printk("Jiffies %x %ld\n\n\n\n", jiffies, jiffies);
> >> 30 for(i=0;i<SZ_4KB;i++)
> >> 31 src = readl(tcpm_base+i);
> >> 32 printk("Jiffies %x %ld\n\n\n\n", jiffies, jiffies);
> >> 33 }
> >> 34 else
> >> 35 printk("unable to map 3MB\n");
> >>
> >> 3) I am getting the following error,
> >>
> >> [ 1.876647] Unable to handle kernel paging request at virtual address
> >> ea82c000
> >> [ 1.880950] pgd = c0004000
> >> [ 1.883636] [ea82c000] *pgd=49818811, *pte=00000000, *ppte=00000000
> >> [ 1.889892] Internal error: Oops: 7 [#1] PREEMPT
> >> [ 1.894500] Modules linked in:
> >> [ 1.897521] CPU: 0 Not tainted (3.0.31-g1080f34-dirty #106)
> >> [ 1.903442] PC is at sand_misc_init+0x4c/0xac
> >> [ 1.907775] LR is at sand_misc_init+0x3c/0xac
> >> [ 1.912109] pc : [<c0022ee0>] lr : [<c0022ed0>] psr: 80000013
> >> [ 1.912139] sp : e982bf98 ip : 00000000 fp : 00000000
> >> [ 1.923553] r10: 00000000 r9 : 00000000 r8 : 00000000
> >> [ 1.928771] r7 : 00000000 r6 : c00461b4 r5 : ea828000 r4 :
> 00000000
> >> [ 1.935272] r3 : 00003fff r2 : 00003ffd r1 : c07ea2cf r0 :
> 00000063
> >> [ 1.941802] Flags: Nzcv IRQs on FIQs on Mode SVC_32 ISA ARM
> >> Segment kernel
> >> [ 1.949096] Control: 10c57c7d Table: 00404059 DAC: 00000015
> >> [ 1.954803]
> >> [ 1.954833] PC: 0xc0022e60:
> >> [ 1.959075] 2e60 c09105f0 c0366554 c07ea27e c07ea296 e3a01000
> e92d4010
> >> e1a02001 eb0a9acd
> >> [ 1.967224] 2e80 e59f3008 e5830008 e3a00001 e8bd8010 c0dd8380
> e92d4037
> >> e3a04000 e3a0063b
> >> [ 1.975402] 2ea0 e3a01901 e1a02004 e5cd4007 e5cd4006 eb00b9aa
> e2505000
> >> 0a000019 e59f3070
> >> [ 1.983551] 2ec0 e59f0070 e5931000 e5932000 eb18a072 e58d4000
> e3033fff
> >> ea000007 e59d2000
> >> [ 1.991699] 2ee0 e7952002 f57ff04f e6ef2072 e5cd2007 e59d2000
> e2822001
> >> e58d2000 e59d2000
> >> [ 1.999877] 2f00 e1520003 dafffff4 e59f3024 e59f0024 e5931000
> e5932000
> >> e28dd00c e8bd4030
> >> [ 2.008026] 2f20 ea18a05d e59f0010 e28dd00c e8bd4030 ea18a059
> c08ea600
> >> c07ea2cf c07ea2e2
> >> [ 2.016174] 2f40 e59f3040 e3a01000 e92d4010 e59f0038 e5932000
> eb0a845a
> >> e59f3030 e3500000
> >> [ 2.024353]
> >> [ 2.024353] LR: 0xc0022e50:
> >> [ 2.028594] 2e50 e3e00015 e8bd81fc c0dd8380 c07ea279 c09105f0
> c0366554
> >> c07ea27e c07ea296
> >> [ 2.036773] 2e70 e3a01000 e92d4010 e1a02001 eb0a9acd e59f3008
> e5830008
> >> e3a00001 e8bd8010
> >> [ 2.044921] 2e90 c0dd8380 e92d4037 e3a04000 e3a0063b e3a01901
> e1a02004
> >> e5cd4007 e5cd4006
> >> [ 2.053070] 2eb0 eb00b9aa e2505000 0a000019 e59f3070 e59f0070
> e5931000
> >> e5932000 eb18a072
> >> [ 2.061248] 2ed0 e58d4000 e3033fff ea000007 e59d2000 e7952002
> f57ff04f
> >> e6ef2072 e5cd2007
> >> [ 2.069396] 2ef0 e59d2000 e2822001 e58d2000 e59d2000 e1520003
> dafffff4
> >> e59f3024 e59f0024
> >> [ 2.077575] 2f10 e5931000 e5932000 e28dd00c e8bd4030 ea18a05d
> e59f0010
> >> e28dd00c e8bd4030
> >> [ 2.085723] 2f30 ea18a059 c08ea600 c07ea2cf c07ea2e2 e59f3040
> e3a01000
> >> e92d4010 e59f0038
> >> [ 2.093872]
> >> [ 2.093902] SP: 0xe982bf18:
> >> [ 2.098144] bf18 382e3120 30393536 00205d35 000000d0 00004fff
> 00003b00
> >> 192d8000 ea82bfff
> >> [ 2.106292] bf38 03b00000 ffffffff e982bf84 c00461b4 00000000
> c0044dac
> >> 00000063 c07ea2cf
> >> [ 2.114440] bf58 00003ffd 00003fff 00000000 ea828000 c00461b4
> 00000000
> >> 00000000 00000000
> >> [ 2.122619] bf78 00000000 00000000 00000000 e982bf98 c0022ed0
> c0022ee0
> >> 80000013 ffffffff
> >> [ 2.130767] bf98 00003ffd 0000a27e 00000000 c0037b4c c0022e94
> c003f3fc
> >> e9814a80 00373231
> >> [ 2.138946] bfb8 00000000 00000000 00000000 00000236 c0037b4c
> c003818c
> >> c00461b4 00000013
> >> [ 2.147094] bfd8 00000000 00000000 00000000 c0008374 00000000
> c0008300
> >> c00461b4 c00461b4
> >> [ 2.155242] bff8 00000000 00000000 00000000 00000001 00000000
> e9817940
> >> c08e8ef4 00000000
> >> [ 2.163421]
> >> [ 2.163421] R1: 0xc07ea24f:
> >> [ 2.167663] a24c 65207265 726f7272 6f6c6220 25206b63 000a646c
> 706f6f6c
> >> 26006425 3e2d6f6c
> >> [ 2.175842] a26c 635f6f6c 6d5f6c74 78657475 6f6f6c00 363c0070
> 6f6f6c3e
> >> 6d203a70 6c75646f
> >> [ 2.183990] a28c 6f6c2065 64656461 363c000a 6f6f6c3e 6f203a70
> 6f207475
> >> 656d2066 79726f6d
> >> [ 2.192138] a2ac 6162000a 6e696b63 69665f67 7300656c 6c657a69
> 74696d69
> >> 74756100 656c636f
> >> [ 2.200317] a2cc 4a007261 69666669 25207365 6c252078 0a0a0a64
> 6e75000a
> >> 656c6261 206f7420
> >> [ 2.208465] a2ec 2070616d 0a424d33 656d7000 65725f6d 6e6f6967
> 333c0073
> >> 656d703e 7325286d
> >> [ 2.216613] a30c 736b3a29 635f7465 74616572 6e615f65 64615f64
> 61662064
> >> 000a6c69 703e343c
> >> [ 2.224792] a32c 3a6d656d 6d6f7320 69687465 6920676e 65762073
> 77207972
> >> 676e6f72 6f79202c
> >> [ 2.232940] a34c 72612075 6c632065 6e69736f 20612067 62206d76
> 696b6361
> >> 6120676e 6c61206e
> >> [ 2.241119]
> >> [ 2.241119] R5: 0xea827f80:
> >> [ 2.245361] 7f80 ******** ******** ******** ******** ********
> ********
> >> ******** ********
> >> [ 2.253509] 7fa0 ******** ******** ******** ******** ********
> ********
> >> ******** ********
> >> [ 2.261688] 7fc0 ******** ******** ******** ******** ********
> ********
> >> ******** ********
> >> [ 2.269836] 7fe0 ******** ******** ******** ******** ********
> ********
> >> ******** ********
> >> [ 2.278015] 8000 00000000 00000000 00000000 00000000 00000000
> 00000000
> >> 00000000 00000000
> >> [ 2.286163] 8020 00000000 00000000 00000000 00000000 00000000
> 00000000
> >> 00000000 00000000
> >> [ 2.294311] 8040 00000000 00000000 00000000 00000000 00000000
> 00000000
> >> 00000000 00000000
> >> [ 2.302490] 8060 00000000 00000000 00000000 00000000 00000000
> 00000000
> >> 00000000 00000000
> >> [ 2.310638]
> >> [ 2.310638] R6: 0xc0046134:
> >> [ 2.314880] 6134 eb038dff eb02a1f9 e1a03007 e1a00005 e1a02006
> eb025566
> >> e59f3008 e5834000
> >> [ 2.323059] 6154 e8bd41f0 ea0259b3 c09059d4 c08fbcd4 c064e808
> c0791c0d
> >> c0958220 e59fc020
> >> [ 2.331207] 6174 e92d4007 e59f301c e59cc000 e1a02001 e59f1014
> e58dc000
> >> eb055aab e3a00000
> >> [ 2.339385] 6194 e8bd800e c0958220 c0791c27 c0791c1b e121f007
> e1a00004
> >> e1a0e006 e1a0f005
> >> [ 2.347534] 61b4 eb02959a e320f000 e59f300c e5932000 e2822001
> e5832000
> >> e12fff1e c0958224
> >> [ 2.355682] 61d4 e59f300c e5932000 e2422001 e5832000 e12fff1e
> c0958224
> >> e12fff1e e12fff1e
> >> [ 2.363861] 61f4 e12fff1e e12fff1e eafffffe e59f3014 e92d4010
> e5933004
> >> e3530000 08bd8010
> >> [ 2.372009] 6214 e12fff33 e8bd8010 c0958224 e59f3014 e1a01000
> e92d4010
> >> e5d30000 e1a0e00f
> >> [ 2.380187] Process swapper (pid: 1, stack limit = 0xe982a2e8)
> >> [ 2.385986] Stack: (0xe982bf98 to 0xe982c000)
> >> [ 2.390319] bf80:
> >> 00003ffd 0000a27e
> >> [ 2.398498] bfa0: 00000000 c0037b4c c0022e94 c003f3fc e9814a80
> 00373231
> >> 00000000 00000000
> >> [ 2.406646] bfc0: 00000000 00000236 c0037b4c c003818c c00461b4
> 00000013
> >> 00000000 00000000
> >> [ 2.414825] bfe0: 00000000 c0008374 00000000 c0008300 c00461b4
> c00461b4
> >> 00000000 00000000
> >> [ 2.423004] [<c0022ee0>] (sand_misc_init+0x4c/0xac) from [<c003f3fc>]
> >> (do_one_initcall+0xd0/0x1a4)
> >> [ 2.431915] [<c003f3fc>] (do_one_initcall+0xd0/0x1a4) from
> [<c0008374>]
> >> (kernel_init+0x74/0x118)
> >> [ 2.440673] [<c0008374>] (kernel_init+0x74/0x118) from [<c00461b4>]
> >> (kernel_thread_exit+0x0/0x8)
> >> [ 2.449462] Code: e58d4000 e3033fff ea000007 e59d2000 (e7952002)
> >> [ 2.455566] ---[ end trace f76f3c76dcb9b9ef ]---
> >> [ 2.460144] Kernel panic - not syncing: Attempted to kill init!
> >> [ 2.466064] [<c004ad10>] (unwind_backtrace+0x0/0x12c) from
> [<c064af70>]
> >> (panic+0x90/0x1bc)
> >> [ 2.474304] [<c064af70>] (panic+0x90/0x1bc) from [<c00eb8dc>]
> >> (do_exit+0xb8/0x734)
> >> [ 2.481842] [<c00eb8dc>] (do_exit+0xb8/0x734) from [<c0048f8c>]
> >> (die+0x208/0x23c)
> >> [ 2.489318] [<c0048f8c>] (die+0x208/0x23c) from [<c004e158>]
> >> (__do_kernel_fault+0x64/0x84)
> >> [ 2.497558] [<c004e158>] (__do_kernel_fault+0x64/0x84) from
> >> [<c004e3e0>] (do_page_fault+0x268/0x288)
> >> [ 2.506683] [<c004e3e0>] (do_page_fault+0x268/0x288) from
> [<c003f270>]
> >> (do_DataAbort+0x34/0x94)
> >> [ 2.515350] [<c003f270>] (do_DataAbort+0x34/0x94) from [<c0044dac>]
> >> (__dabt_svc+0x4c/0x60)
> >> [ 2.523590] Exception stack(0xe982bf50 to 0xe982bf98)
> >> [ 2.528625] bf40: 00000063
> c07ea2cf
> >> 00003ffd 00003fff
> >> [ 2.536804] bf60: 00000000 ea828000 c00461b4 00000000 00000000
> 00000000
> >> 00000000 00000000
> >> [ 2.544952] bf80: 00000000 e982bf98 c0022ed0 c0022ee0 80000013
> ffffffff
> >> [ 2.551544] [<c0044dac>] (__dabt_svc+0x4c/0x60) from [<c0022ee0>]
> >> (sand_misc_init+0x4c/0xac)
> >> [ 2.559967] [<c0022ee0>] (sand_misc_init+0x4c/0xac) from [<c003f3fc>]
> >> (do_one_initcall+0xd0/0x1a4)
> >> [ 2.568908] [<c003f3fc>] (do_one_initcall+0xd0/0x1a4) from
> [<c0008374>]
> >> (kernel_init+0x74/0x118)
> >> [ 2.577667] [<c0008374>] (kernel_init+0x74/0x118) from [<c00461b4>]
> >> (kernel_thread_exit+0x0/0x8)
> >>
> >>
> >> Any idea what went wrong.
> >> I am sure about the ioremap() start address, thats what i reserved in
> >> ATAGS.
> >>
> >> Thanks
> >> Sandeep
> >>
> >>
> >> On Thu, Feb 28, 2013 at 10:30 AM, sandeep kumar
> >> <coolsandyforyou at gmail.com> wrote:
> >>>
> >>> >1. use early_param to get the physical start address and size of
> >>> > test_region, or you can just ignore this step and hard code to 510M
> and 2M
> >>> > for test purpose only.
> >>>
> >>> >2. use ioremap_nocache() to map this region to a virtual region. note
> >>> > that this funtion may fail if you are asking a very large vitual
> memroy
> >>> > region.
> >>>
> >>> Sounds good, i am gonna try this and let you know.. :)
> >>>
> >>>
> >>> On Wed, Feb 27, 2013 at 8:19 PM, buyitian <buyit at live.cn> wrote:
> >>>>
> >>>> ----------------------------------------
> >>>> > From: buyit at live.cn
> >>>> > To: coolsandyforyou at gmail.com; kernelnewbies at kernelnewbies.org
> >>>> > Subject: RE: How to measure the RAM read/write performance
> >>>> > Date: Wed, 27 Feb 2013 22:33:15 +0800
> >>>> > CC: dhylands at gmail.com
> >>>> >
> >>>> > ________________________________
> >>>> > > From: coolsandyforyou at gmail.com
> >>>> > > Date: Tue, 26 Feb 2013 17:01:54 +0530
> >>>> > > Subject: How to measure the RAM read/write performance
> >>>> > > To: kernelnewbies at kernelnewbies.org
> >>>> > > CC: dhylands at gmail.com
> >>>> > >
> >>>> > > Hi All
> >>>> > > In performance benchmark tools, When we profile read/write timings
> >>>> > > mostly, those read/writes are done to cache only.
> >>>> > >
> >>>> > > I want to measure my DDR(RAM chip) performance.
> >>>> > > So i want to make sure, every read/write should happen to DDR RAM
> >>>> > > chip only.
> >>>> > >
> >>>> > > How can i achieve this...Any ideas/suggestions...?
> >>>> >
> >>>> > try to reserve a large region from bootloader(L4 in Qualcomm
> >>>> > platform), let's say it is 10MB continuous physical memory.
> >>>>
> >>>> sorry, to be accurate, reserve physical memory is done by kernel
> >>>> cmdline, this cmdline parameter can be passed from L4 to kernel, or
> configed
> >>>> by kernel itself.
> >>>> the cmdline will be like below:
> >>>> mem=510M at 0 test_region=2M at 510M
> >>>>
> >>>> above example tells kernel you have totally 512MB physical memory, but
> >>>> kernel will only use the first 510MB, the latter 2MB memory is used
> by you.
> >>>> how to map and use this region depends on you.
> >>>>
> >>>> > in kernel, map this region to an continuous virtual region, note
> that
> >>>> > the pgprot should be uncachable since you want to test without
> cache.
> >>>>
> >>>> 1. use early_param to get the physical start address and size of
> >>>> test_region, or you can just ignore this step and hard code to 510M
> and 2M
> >>>> for test purpose only.
> >>>>
> >>>> 2. use ioremap_nocache() to map this region to a virtual region. note
> >>>> that this funtion may fail if you are asking a very large vitual
> memroy
> >>>> region.
> >>>>
> >>>> > once you configed like this, you can read/write to this vitual
> region
> >>>> > without data cache invovled.
> >>>> >
> >>>> > >
> >>>> > > --
> >>>> > > With regards,
> >>>> > > Sandeep Kumar Anantapalli,
> >>>> > >
> >>>> > > _______________________________________________ Kernelnewbies
> >>>> > > mailing
> >>>> > > list Kernelnewbies at kernelnewbies.org
> >>>> > > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> >>>> > _______________________________________________
> >>>> > Kernelnewbies mailing list
> >>>> > Kernelnewbies at kernelnewbies.org
> >>>> > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> >>>
> >>>
> >>>
> >>>
> >>> --
> >>> With regards,
> >>> Sandeep Kumar Anantapalli,
> >>
> >>
> >>
> >>
> >> --
> >> With regards,
> >> Sandeep Kumar Anantapalli,
> >
> >
> >
> >
> > --
> > With regards,
> > Sandeep Kumar Anantapalli,
> >
> > _______________________________________________
> > Kernelnewbies mailing list
> > Kernelnewbies at kernelnewbies.org
> > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> >
>
--
With regards,
Sandeep Kumar Anantapalli,
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