[U-Boot] [PATCH 1/2] mtd: vf610_nfc: remove caching of page in buffer

[Stefan Agner]

On 2015-04-02 22:30, Bill Pringlemeir wrote:
> On  2 Apr 2015, stefan at agner.ch wrote:
> 
>> To improve performance we remember the current page in the buffer
>> and avoid reading it twice. This implicit page cache increases
>> complexity while does not increase performance in real world cases.
>> This patch removes that feature.
>> ---
>> As discussed in the other patchset...
>> http://thread.gmane.org/gmane.comp.boot-loaders.u-boot/215802
> 
>> ...I did some performance measurements:
> 
>> Time to "Starting kernel ..."
>> - without bad block scan & with UBIFS fastmap: 2.02s
>> - with bad block scan & with UBIFS fastmap: 3.99s
>> - without bad block scan & without UBIFS fastmap: 4.42s
>> - with bad block scan & without UBIFS fastmap: 6.38s
> 
>> Without page cache (with this patch applied):
>> Time to "Starting kernel ..."
>> - without bad block scan & with UBIFS fastmap: 2.02s
>> - with bad block scan & with UBIFS fastmap: 4.01s
>> - without bad block scan & without UBIFS fastmap: 4.41s
>> - with bad block scan & without UBIFS fastmap: 6.39s
> 
> [snip]
> 
> I also measured 'write performance' with the mtd_speedtest (performing
> similar patch to the Linux driver) and I see no difference.  I think a
> write benchmark is more appropriate to test this functionality?  While
> at least it seems that neither read nor write is affected by the
> simplification.

On U-Boot, I just benchmarked the overall boot time since this is most
important for us. I plan to (re-)integrate the changes into the Linux
driver and check the performance again later this week.

Thanks for for the write test. So I can take this as a Ack?

I will send all the NFC changes in one patchset as v2 probably later
today.

--
Stefan