Esben Nielsen wrote:
On Thu, 16 Feb 2006, Arjan van de Ven wrote:
On Thu, 2006-02-16 at 20:06 +0100, Esben Nielsen wrote:
Why does the list have to be in userspace?
because it's faster ;)
Faster???
As I see it, extra manipulations have to be done even in the non-congested
case: Every time the lock is taken the locking thread has to add the lock
to a the list, and reversely remove the lock from the list. I.e.
instructions are _added_ to the fast path where you stay purely in
userspace.
I am ofcourse comparing to a solution where you do a syscall on everytime
you do a lock.
The whole *point* of futexes is that on uncontested operations you don't
have to do a syscall. Thus, if you can avoid taking a syscall while
still getting reliability, you'll be faster.
Dropping to kernelspace isn't free.
Chris
-
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]
