Re: Performance measurement: Building openembedded-core with and without overclocking on C-i7 2600K

[Ulf Samuelsson <ulf_samuelsson@telia.com>]

2011-10-23 19:50, Roman Khimov skrev:
> ? ????????? ?? 18 ??????? 2011 10:03:25 ????? Ulf Samuelsson ???????:
>> Also what happens if it it built on a fast SSD, or even a RAMdisk?
> Our main build server has two Xeons X5670 with 96 GB of RAM. It's running 24×7
> cyclicly doing clean isolated builds of all our OE projects (currently five).
> "Isolated" means that the the actual build is done inside a container (LXC)
> with no network available at all, that is a requirement for all our builds, to
> be able to take one tarball of sources, one tarball of OE tree and build the
> project somewhere in a nuclear bunker.
>
> The system is configured in such way that container is located on tmpfs (with
> size of 50 GB). The most complex build takes about hour and a half on this
> system occupying about 45 GB of space in a ramdisk.
>
> So today I tried to get some RAM vs. Linux cache statistics and switched this
> mount point over to newly created 60 GB LVM partition with ext4 on RAID0 array
> consisting of two SAS 15K drives.
>
> The system made builds for three projects is this configuration and I see no
> difference at all, usual 1-2 minutes deviation. Granted, the system has quite
> powerful disks (RAID array gives about 380 MB/sec on hdparm) and things might
> be a little different on plain SATA drives, but frankly I'd expected to see
> the difference anyway since there are lots of small files involved in a build.
>
> Maybe I should try to further degrade the disk system by creating some
> encrypted volume inside LVM, but still from what I see Linux caching and
> buffering works good enough, just give it as much RAM as you can.
>
> But then also what you'll get from RAM or disk or even CPU upgrade depends on
> what type of build you have. Upgrading developers build servers from pair of
> 4-core Opterons (don't remember exact model) with 8 GB of RAM to pair of Xeons
> E5620 with 24 GB of RAM with comparable disks gave about 20-30% of build time
> reduction for one project and 50% for another. But that builds are not
> isolated and use icecc cluster with all build servers available to the
> cluster, maybe that helps also in our situation.
>

Thanks,

I tried installing 32 bit Ubuntu 11.10 on a HDD and got results,
which are very close to the results of 64 bit ubuntu 11.10, but when I tried
hdparm the 32 bit system had 50 MB/s and the 64 bit system
had 100-110 MB/s so they are not comparable.

Also tried putting tmp/sysroots on a 3 GB tmpfs, and that only
made the build a couple of minutes faster on a 1 hour build.



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-- 
Best Regards
Ulf Samuelsson