[lkml]   [1999]   [Nov]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: spin_unlock optimization(i386)
On 30 Nov 1999, Stefan Monnier wrote:

>>>>>> "Andrea" == Andrea Arcangeli <> writes:
>> Because the write buffer as documented is not allowed to show changes to
>> the other cpus not in processor order. It can only delay the writes
>> undefinitely but that make no difference at all for SMP.
>Of course it makes a difference:
> A = 1 B = 0
> read B read A

For the above it make no difference if there's a write buffer or not.

Just replace the A = 1 and B = 0 with a `make A visible to other CPUs' and
`make B visible to other CPUs' and move the two writes some hour before.

Speculation is a completly different issue.

Feel free to ask further if I am not been clear enough.


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
Please read the FAQ at

 \ /
  Last update: 2005-03-22 13:55    [W:0.050 / U:5.944 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site