Re: [Valgrind-users] Execution of a dirty helper: atomic?

2012-12-31 Thread Philippe Waroquiers
On Sun, 2012-12-30 at 22:45 +0100, Emilio Coppa wrote: Thank both of you for your answers. Each CPU core may switch logical threads only at a superblock boundary, but mutual exclusion between threads on different CPU cores is not guaranteed. For

Re: [Valgrind-users] Execution of a dirty helper: atomic?

2012-12-31 Thread Patrick J. LoPresti
On Mon, Dec 31, 2012 at 4:48 AM, Philippe Waroquiers philippe.waroqui...@skynet.be wrote: It is even not ok to use an atomic instruction : first tests have shown that having one atomic instruction on this path makes a multi-threaded Valgrind slower than a serialised Valgrind. You mean a

Re: [Valgrind-users] Execution of a dirty helper: atomic?

2012-12-28 Thread Julian Seward
It is hard to answer this question since it is not really clear what you mean by atomic here. Can you clarify? J On Thursday, December 27, 2012, Emilio Coppa wrote: Hi all, I would like to know if Valgrind assures atomic execution of a dirty helper. In more detail I am interested in the

Re: [Valgrind-users] Execution of a dirty helper: atomic?

2012-12-28 Thread Emilio Coppa
Hi, It is hard to answer this question since it is not really clear what you mean by atomic here. Can you clarify? I mean atomic in the sense of no thread switching/interleaving. Emilio. -- Master HTML5, CSS3,

Re: [Valgrind-users] Execution of a dirty helper: atomic?

2012-12-28 Thread Julian Seward
I mean atomic in the sense of no thread switching/interleaving. In that case, yes it is atomic. That is, V will not switch threads within a superblock. It can only switch threads at superblock boundaries. J --

Re: [Valgrind-users] Execution of a dirty helper: atomic?

2012-12-28 Thread John Reiser
On 12/28/2012 07:57 AM, Julian Seward wrote: I mean atomic in the sense of no thread switching/interleaving. In that case, yes it is atomic. That is, V will not switch threads within a superblock. It can only switch threads at superblock boundaries.To Today this is true. However, there

[Valgrind-users] Execution of a dirty helper: atomic?

2012-12-27 Thread Emilio Coppa
Hi all, I would like to know if Valgrind assures atomic execution of a dirty helper. In more detail I am interested in the situation: --- access to a memory cell call to a dirty helper X() [inserted by unsafeIRDirty_0_N] execution of X() --- Is this executed atomically by Valgrind? I know that