On Mon, May 23, 2011 at 2:25 PM, Andrei Warkentin <andreiw@xxxxxxxxxxxx> wrote: > On Mon, May 23, 2011 at 7:40 AM, Jaehoon Chung <jh80.chung@xxxxxxxxxxx> wrote: >> Hi A.. >> >> I tested your patch..(using CMD23) >> my environment is the below. >> eMMC card : Sandisk SEM8G (eMMC 4.3+) >> buswidth : 4bit (SDR) >> AP : C110 >> benchmark : IOzone >> >> I want to know how do you think about this result? >> (i can't see your results) >> > > I think that you should use my tool to measure I/O performance. > Because I want to see the mins, maxes, average and > std dev. Iozone adds way too much noise to the data. You can run it 5 > times in a row and get completely different numbers. Please use > https://github.com/andreiw/superalign. > > For a more realistic test you can try performing 20000 sqlite inserts > or something of the sort and timing that. > > A > Additionally, be careful how you do your testing. I don't want to sound obvious, but, to ensure you can actually compare the collected data against each other - 1) Disable all power/frequency scaling/management/gating, suspend/resume, etc. 2) Make sure nothing else uses the eMMC. No root mounted fs, nothing. 3) Make sure you are avoiding block cache and file system. You want direct block I/O. 4) For extra extra extra reliable results - Make sure you are not rebooting across testing. You will need to add a flag so you can disable CMD23 on the fly via debugfs. For sqlite testing some other helpful hints - 1) Unmount partition containing files on which the SQLite test operates. 2) Perform BLKDISCARD over the partition. 3) Format with desired file system. 4) Mount. 6) Sync && echo 3 > /proc/sys/vm/drop_caches 7) Perform test. 8) Umount. 9) Repeat from (1) A -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
