Attached is .config for 2.6.21...pls let me know if you see any issues with it. Thanks a lot! On Wed, Sep 16, 2009 at 1:46 AM, Linux Raid Study <linuxraid.study@xxxxxxxxx> wrote: > Attached is .config for 2.6.27 kernel. Its mips64....Do you see > anything wrong with it? > > I don't yet access to my m/c for 2.6.21...would email that later. > > Any feedback... > > Thanks! > > On Wed, Sep 16, 2009 at 1:21 AM, Majed B. <majedb@xxxxxxxxx> wrote: >> Would you mind attaching both kernel config files and emailing them? >> Also, did you compile your own kernels or do you run certain images? >> >> On Wed, Sep 16, 2009 at 11:19 AM, Majed B. <majedb@xxxxxxxxx> wrote: >>> I've run my own tests a few days back on a machine I have, but I >>> haven't compared the results to tests on the same machine with older >>> kernels. >>> >>> I have attached my machine's kernel config file. >>> >>> I run an Ubuntu 9.04 Server - Kernel 2.6.28-15-server. >>> >>> On Wed, Sep 16, 2009 at 11:10 AM, Linux Raid Study >>> <linuxraid.study@xxxxxxxxx> wrote: >>>> Yes - as far as Raid/disk-controller stuff is concerned, they are >>>> same. BTW, is there anything specific you would like me to check. >>>> >>>> Have you done similar tests? Do you see any perf drop? >>>> >>>> Thanks! >>>> >>>> On Wed, Sep 16, 2009 at 1:06 AM, Majed B. <majedb@xxxxxxxxx> wrote: >>>>> Did you compare both kernel's config files to see whether these >>>>> kernels have been compiled with different options? >>>>> >>>>> On Wed, Sep 16, 2009 at 10:57 AM, Linux Raid Study >>>>> <linuxraid.study@xxxxxxxxx> wrote: >>>>>> Hi Majed, All: >>>>>> >>>>>> I'm using the default scheduler with 2.6.21 and 2.6.27...do you know >>>>>> if there is any difference? >>>>>> >>>>>> I rechecked the perf today - everything (i.e. disks, disk controller >>>>>> etc) remaining the same, I see around 45MB/s difference in performance >>>>>> when I change kernel from 2.6.21 to 2.6.27. I issue following cmd to >>>>>> see performance: >>>>>> hdparm -t /dev/md0 >>>>>> >>>>>> FYI...I'm using Seagate HDDs (7200 RPM) with RocketRaid 2310 controller. >>>>>> >>>>>> Any ideas...I have tried blockdev readahead option and it helps but >>>>>> still not enough... >>>>>> >>>>>> Thanks a lot! >>>>>> >>>>>> On Wed, Sep 9, 2009 at 4:52 PM, Majed B. <majedb@xxxxxxxxx> wrote: >>>>>>> Are you sure you're using the same Kernel Scheduler on both kernels? >>>>>>> >>>>>>> Have you checked and verified that the same drivers are being loaded? >>>>>>> (IDE vs. AHCI -- proprietary drivers vs. open source) >>>>>>> >>>>>>> This is interesting! >>>>>>> >>>>>>> On Thu, Sep 10, 2009 at 1:54 AM, Linux Raid >>>>>>> Study<linuxraid.study@xxxxxxxxx> wrote: >>>>>>>> Hello: >>>>>>>> >>>>>>>> I'm benchmarking RAID5 Read performance with 4 disks and notice perf >>>>>>>> drop when using kernel 2.6.27. >>>>>>>> The perf with 2.6.27 is 150MB/s whereas with kernel 2.6.21 (and same >>>>>>>> setup), the perf is 180MB/s/ >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> Some of the tests I have done: >>>>>>>> 1. I ran experiments using iozone also but notice that READ perf with >>>>>>>> RAID5 in 2.6.27 is ~30% less as compared to 2.6.21. >>>>>>>> Write perf is similar but Read is an issue. >>>>>>>> >>>>>>>> 2. On 2.6.27, I played around with chunk size and blocksize parameters >>>>>>>> and got ~5% improvement but not much. I used following cmds: >>>>>>>> >>>>>>>> #mdadm --create /dev/md0 --level=5 --assume-clean --raid-devices=4 >>>>>>>> /dev/sda /dev/sdb /dev/sdc /dev/sdd --chunk=32 >>>>>>>> #mke2fs -b 4096 -E stride=8 /dev/md0 >>>>>>>> >>>>>>>> #time dd if=/dev/md0 of=/dev/null bs=94208 count=1024 >>>>>>>> >>>>>>>> >>>>>>>> Is this perf drop a known issue? Can someone please recommend some >>>>>>>> performance tuning tips? >>>>>>>> >>>>>>>> Thanks a lot for your time and help! >>>>>>>> -- >>>>>>>> To unsubscribe from this list: send the line "unsubscribe linux-raid" in >>>>>>>> the body of a message to majordomo@xxxxxxxxxxxxxxx >>>>>>>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> -- >>>>>>> Majed B. >>>>>>> >>>>>> >>>>> >>>>> >>>>> >>>>> -- >>>>> Majed B. >>>>> >>>> >>> >>> >>> >>> -- >>> Majed B. >>> >> >> >> >> -- >> Majed B. >> >
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.config.2.6.21
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