Test RAM read/write speed

[Peter Senna Tschudin]

On Tue, Sep 30, 2014 at 10:02 PM, Ssagarr Patil <hugarsagar at outlook.com> wrote:
> Hi,
>
> ----------------------------------------
>> Date: Tue, 30 Sep 2014 17:49:42 +0200
>> Subject: Re: Test RAM read/write speed
>> From: peter.senna at gmail.com
>> To: Valdis.Kletnieks at vt.edu
>> CC: hugarsagar at outlook.com; kernelnewbies at kernelnewbies.org
>>
>> I use the memtest86+ numbers about memory speed. It gives numbers for
>> RAM and different cache levels.
>>
> you mean numbers for read/write ?
I don't know. Check this out:
https://plus.google.com/+PeterSenna/posts/iw6p2ZSU8VE

>
>> On Mon, Sep 29, 2014 at 11:42 PM, <Valdis.Kletnieks at vt.edu> wrote:
>>> On Tue, 30 Sep 2014 02:53:05 +0530, Ssagarr Patil said:
>>>
>>>> Is there any benchmarking tool to test read/write speed on Linux and which works on ARM ?
>>>
>>> This is always a hairy problem. Do you care about the memory speed of the
>>> DIMM, or the actual *effective* memory speed? They can be very different,
>>> due to the effects of L1/2/3 cache (both positive if there's a cache hit,
>>> and negative if you need a cache line load, or if you need a line load
>>> that requires a cache line writeback first), whether or not you have
>>> a TLB active, and whether *that* has a hit or miss (which varies considerably
>>> if you're walking an array and hitting a miss every 4K bytes, versus
>>> walking a nest of pointers where you get a TLB miss almost every reference),
>>> and a bunch of other issues I lack the caffeine to enumerate...
>>>
>>> And of course, the *effective* speed (which is what you should probably care
>>> about rather than the *rated* speed) will differ based on workload due to
>>> the factors listed above....
>>>
> May be a tool is needed at uboot level to test the speeds.
>
> Thanks.
> --Sagar
>
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>>
>>
>>
>> --
>> Peter
>>
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>



-- 
Peter