Re: [PATCH] doc: memory-barriers.txt: Correct example for reorderings
On Tue, Sep 2, 2014 at 12:08 PM, Paul E. McKenney wrote: > Could you please adjust in this way? Again, the point is to be the > first few items in a full set of permutations, not to illustrate selected > orderings/outcomes. > OK, if that is the case then replacing x with y is much easier. I will send an updated patch. Thanks! -- Pranith -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] doc: memory-barriers.txt: Correct example for reorderings
On Thu, Aug 28, 2014 at 05:45:10PM -0400, Pranith Kumar wrote: > On Thu, Aug 28, 2014 at 5:39 PM, Paul E. McKenney > wrote: > > On Thu, Aug 28, 2014 at 05:15:50PM -0400, Pranith Kumar wrote: > >> On Thu, Aug 28, 2014 at 5:00 PM, Paul E. McKenney > >> wrote: > >> > > >> > I am really confused by the ordering of the new lines, as I would have > >> > expected the "x"s to be replaced with "y"s and vice versa. But the > >> > ordering of the various combinations does not matter, and each line > >> > looks OK. > >> > >> Since x = A was replaced by x = B and y = B was replaced by y = A, I > >> just converted all x = load A to x = load B. Similarly for y. I think > >> we can do either this or as you suggested replacing x's with y's. > > > > Fair enough. The other thing that confused me was the "STORE B=4," > > showing up early in your replacement. > > So I converted > > STORE A=3, x=LOAD A->3 > > to > > STORE B=4, x=LOAD B->4 > > since the later load into x wanted an updated value of B and not the > default. That is the reason you see STORE B = 4 in place of STORE A = > 3 Fair enough. However, the list is supposed to be part of the full set of 24 possible outcomes. Many readers would therefore expect the permutations to be ordered in some way, so that the first column would have six of one thing, six of the next thing, and so on, according to some pattern. Could you please adjust in this way? Again, the point is to be the first few items in a full set of permutations, not to illustrate selected orderings/outcomes. Thanx, Paul -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] doc: memory-barriers.txt: Correct example for reorderings
On Thu, Aug 28, 2014 at 05:45:10PM -0400, Pranith Kumar wrote: On Thu, Aug 28, 2014 at 5:39 PM, Paul E. McKenney paul...@linux.vnet.ibm.com wrote: On Thu, Aug 28, 2014 at 05:15:50PM -0400, Pranith Kumar wrote: On Thu, Aug 28, 2014 at 5:00 PM, Paul E. McKenney paul...@linux.vnet.ibm.com wrote: I am really confused by the ordering of the new lines, as I would have expected the xs to be replaced with ys and vice versa. But the ordering of the various combinations does not matter, and each line looks OK. Since x = A was replaced by x = B and y = B was replaced by y = A, I just converted all x = load A to x = load B. Similarly for y. I think we can do either this or as you suggested replacing x's with y's. Fair enough. The other thing that confused me was the STORE B=4, showing up early in your replacement. So I converted STORE A=3, x=LOAD A-3 to STORE B=4, x=LOAD B-4 since the later load into x wanted an updated value of B and not the default. That is the reason you see STORE B = 4 in place of STORE A = 3 Fair enough. However, the list is supposed to be part of the full set of 24 possible outcomes. Many readers would therefore expect the permutations to be ordered in some way, so that the first column would have six of one thing, six of the next thing, and so on, according to some pattern. Could you please adjust in this way? Again, the point is to be the first few items in a full set of permutations, not to illustrate selected orderings/outcomes. Thanx, Paul -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] doc: memory-barriers.txt: Correct example for reorderings
On Tue, Sep 2, 2014 at 12:08 PM, Paul E. McKenney paul...@linux.vnet.ibm.com wrote: Could you please adjust in this way? Again, the point is to be the first few items in a full set of permutations, not to illustrate selected orderings/outcomes. OK, if that is the case then replacing x with y is much easier. I will send an updated patch. Thanks! -- Pranith -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] doc: memory-barriers.txt: Correct example for reorderings
On Thu, Aug 28, 2014 at 5:39 PM, Paul E. McKenney wrote: > On Thu, Aug 28, 2014 at 05:15:50PM -0400, Pranith Kumar wrote: >> On Thu, Aug 28, 2014 at 5:00 PM, Paul E. McKenney >> wrote: >> > >> > I am really confused by the ordering of the new lines, as I would have >> > expected the "x"s to be replaced with "y"s and vice versa. But the >> > ordering of the various combinations does not matter, and each line >> > looks OK. >> >> Since x = A was replaced by x = B and y = B was replaced by y = A, I >> just converted all x = load A to x = load B. Similarly for y. I think >> we can do either this or as you suggested replacing x's with y's. > > Fair enough. The other thing that confused me was the "STORE B=4," > showing up early in your replacement. > So I converted STORE A=3, x=LOAD A->3 to STORE B=4, x=LOAD B->4 since the later load into x wanted an updated value of B and not the default. That is the reason you see STORE B = 4 in place of STORE A = 3 -- Pranith -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] doc: memory-barriers.txt: Correct example for reorderings
On Thu, Aug 28, 2014 at 05:15:50PM -0400, Pranith Kumar wrote: > On Thu, Aug 28, 2014 at 5:00 PM, Paul E. McKenney > wrote: > > > > I am really confused by the ordering of the new lines, as I would have > > expected the "x"s to be replaced with "y"s and vice versa. But the > > ordering of the various combinations does not matter, and each line > > looks OK. > > Since x = A was replaced by x = B and y = B was replaced by y = A, I > just converted all x = load A to x = load B. Similarly for y. I think > we can do either this or as you suggested replacing x's with y's. Fair enough. The other thing that confused me was the "STORE B=4," showing up early in your replacement. Thanx, Paul -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] doc: memory-barriers.txt: Correct example for reorderings
On Thu, Aug 28, 2014 at 5:00 PM, Paul E. McKenney wrote: > > I am really confused by the ordering of the new lines, as I would have > expected the "x"s to be replaced with "y"s and vice versa. But the > ordering of the various combinations does not matter, and each line > looks OK. > Since x = A was replaced by x = B and y = B was replaced by y = A, I just converted all x = load A to x = load B. Similarly for y. I think we can do either this or as you suggested replacing x's with y's. -- Pranith -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] doc: memory-barriers.txt: Correct example for reorderings
On Thu, Aug 28, 2014 at 5:00 PM, Paul E. McKenney paul...@linux.vnet.ibm.com wrote: I am really confused by the ordering of the new lines, as I would have expected the xs to be replaced with ys and vice versa. But the ordering of the various combinations does not matter, and each line looks OK. Since x = A was replaced by x = B and y = B was replaced by y = A, I just converted all x = load A to x = load B. Similarly for y. I think we can do either this or as you suggested replacing x's with y's. -- Pranith -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] doc: memory-barriers.txt: Correct example for reorderings
On Thu, Aug 28, 2014 at 05:15:50PM -0400, Pranith Kumar wrote: On Thu, Aug 28, 2014 at 5:00 PM, Paul E. McKenney paul...@linux.vnet.ibm.com wrote: I am really confused by the ordering of the new lines, as I would have expected the xs to be replaced with ys and vice versa. But the ordering of the various combinations does not matter, and each line looks OK. Since x = A was replaced by x = B and y = B was replaced by y = A, I just converted all x = load A to x = load B. Similarly for y. I think we can do either this or as you suggested replacing x's with y's. Fair enough. The other thing that confused me was the STORE B=4, showing up early in your replacement. Thanx, Paul -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] doc: memory-barriers.txt: Correct example for reorderings
On Thu, Aug 28, 2014 at 5:39 PM, Paul E. McKenney paul...@linux.vnet.ibm.com wrote: On Thu, Aug 28, 2014 at 05:15:50PM -0400, Pranith Kumar wrote: On Thu, Aug 28, 2014 at 5:00 PM, Paul E. McKenney paul...@linux.vnet.ibm.com wrote: I am really confused by the ordering of the new lines, as I would have expected the xs to be replaced with ys and vice versa. But the ordering of the various combinations does not matter, and each line looks OK. Since x = A was replaced by x = B and y = B was replaced by y = A, I just converted all x = load A to x = load B. Similarly for y. I think we can do either this or as you suggested replacing x's with y's. Fair enough. The other thing that confused me was the STORE B=4, showing up early in your replacement. So I converted STORE A=3, x=LOAD A-3 to STORE B=4, x=LOAD B-4 since the later load into x wanted an updated value of B and not the default. That is the reason you see STORE B = 4 in place of STORE A = 3 -- Pranith -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH] doc: memory-barriers.txt: Correct example for reorderings
Correct the example of memory orderings in memory-barriers.txt Commit 615cc2c9cf95 "Documentation/memory-barriers.txt: fix important typo re memory barriers" changed the assignment to x and y. Change the rest of the example to match this change. Reported-by: Ganesh Rapolu Signed-off-by: Pranith Kumar --- Documentation/memory-barriers.txt | 22 +++--- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt index a4de88f..cf31875 100644 --- a/Documentation/memory-barriers.txt +++ b/Documentation/memory-barriers.txt @@ -121,22 +121,22 @@ For example, consider the following sequence of events: The set of accesses as seen by the memory system in the middle can be arranged in 24 different combinations: - STORE A=3, STORE B=4, x=LOAD A->3,y=LOAD B->4 - STORE A=3, STORE B=4, y=LOAD B->4,x=LOAD A->3 - STORE A=3, x=LOAD A->3,STORE B=4, y=LOAD B->4 - STORE A=3, x=LOAD A->3,y=LOAD B->2,STORE B=4 - STORE A=3, y=LOAD B->2,STORE B=4, x=LOAD A->3 - STORE A=3, y=LOAD B->2,x=LOAD A->3,STORE B=4 - STORE B=4, STORE A=3, x=LOAD A->3,y=LOAD B->4 + STORE A=3, STORE B=4, x=LOAD B->4,y=LOAD A->3 + STORE A=3, STORE B=4, y=LOAD A->3,x=LOAD B->4 + STORE B=4, x=LOAD B->4,STORE A=3, y=LOAD A->3 + STORE A=3, x=LOAD B->2,y=LOAD A->3,STORE B=4 + STORE B=4, y=LOAD A->1,STORE A=3, x=LOAD B->4 + STORE B=4, y=LOAD A->1,x=LOAD B->4,STORE A=3 + STORE B=4, STORE A=3, x=LOAD B->4,y=LOAD A->3 STORE B=4, ... ... and can thus result in four different combinations of values: - x == 1, y == 2 - x == 1, y == 4 - x == 3, y == 2 - x == 3, y == 4 + x == 2, y == 1 + x == 2, y == 3 + x == 4, y == 1 + x == 4, y == 3 Furthermore, the stores committed by a CPU to the memory system may not be -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH] doc: memory-barriers.txt: Correct example for reorderings
Correct the example of memory orderings in memory-barriers.txt Commit 615cc2c9cf95 Documentation/memory-barriers.txt: fix important typo re memory barriers changed the assignment to x and y. Change the rest of the example to match this change. Reported-by: Ganesh Rapolu ganesh.rap...@hotmail.com Signed-off-by: Pranith Kumar bobby.pr...@gmail.com --- Documentation/memory-barriers.txt | 22 +++--- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt index a4de88f..cf31875 100644 --- a/Documentation/memory-barriers.txt +++ b/Documentation/memory-barriers.txt @@ -121,22 +121,22 @@ For example, consider the following sequence of events: The set of accesses as seen by the memory system in the middle can be arranged in 24 different combinations: - STORE A=3, STORE B=4, x=LOAD A-3,y=LOAD B-4 - STORE A=3, STORE B=4, y=LOAD B-4,x=LOAD A-3 - STORE A=3, x=LOAD A-3,STORE B=4, y=LOAD B-4 - STORE A=3, x=LOAD A-3,y=LOAD B-2,STORE B=4 - STORE A=3, y=LOAD B-2,STORE B=4, x=LOAD A-3 - STORE A=3, y=LOAD B-2,x=LOAD A-3,STORE B=4 - STORE B=4, STORE A=3, x=LOAD A-3,y=LOAD B-4 + STORE A=3, STORE B=4, x=LOAD B-4,y=LOAD A-3 + STORE A=3, STORE B=4, y=LOAD A-3,x=LOAD B-4 + STORE B=4, x=LOAD B-4,STORE A=3, y=LOAD A-3 + STORE A=3, x=LOAD B-2,y=LOAD A-3,STORE B=4 + STORE B=4, y=LOAD A-1,STORE A=3, x=LOAD B-4 + STORE B=4, y=LOAD A-1,x=LOAD B-4,STORE A=3 + STORE B=4, STORE A=3, x=LOAD B-4,y=LOAD A-3 STORE B=4, ... ... and can thus result in four different combinations of values: - x == 1, y == 2 - x == 1, y == 4 - x == 3, y == 2 - x == 3, y == 4 + x == 2, y == 1 + x == 2, y == 3 + x == 4, y == 1 + x == 4, y == 3 Furthermore, the stores committed by a CPU to the memory system may not be -- 1.9.1 -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
