Re: high cpu load for random write

Piavlo
2009-07-01T08:51:13Z

Chris Mason wrote:
> checksumming (which is constant for creating the file and for random
> writes) and the second is the cost of maintaining back references for
> the file data extent.
>
> In btrfs, we track the owners of each extent, which makes repair, volume
> management and other things much easier. Small random writes make for a
> lot of extents, and so they also make for a lot of tracking.
>
I've no problem with high cpu load on dedicated storage servers, but it
does not seems right for desktop usage.
Please correct me if i'm wrong.

Alex
> In general, you'll find that mount -o ssd will be faster here, just
> because it forces the allocator into more sequential allocations for
> this workload.
>
> You'll find that mount -o nodatacow uses much less CPU time, but this
> disables checksumming and a few other advanced features.
>
> -chris
>