Re: O_DIRECT question

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Michael Tokarev wrote:
[]
> After all the explanations, I still don't see anything wrong with the
> interface itself.  O_DIRECT isn't "different semantics" - we're still
> writing and reading some data.  Yes, O_DIRECT and non-O_DIRECT usages
> somewhat contradicts with each other, but there are other ways to make
> the two happy, instead of introducing alot of stupid, complex, and racy
> code all over.

By the way.  I just ran - for fun - a read test of a raid array.

Reading blocks of size 512kbytes, starting at random places on a 400Gb
array, doing 64threads.

 O_DIRECT: 336.73 MB/sec.
!O_DIRECT: 146.00 MB/sec.

Quite a... difference here.

Using posix_fadvice() does not improve it.

/mjt
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux