Re: [boost] GSOC 2015 : Project on Concurrent Hash Tables

On 6 Mar 2015 at 11:29, Amarnath V A wrote:

On Fri, Mar 6, 2015 at 9:49 AM, Niall Douglas wrote:

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You had the situation inverted. New buckets are normally locked (1) until the copy/move is complete. Old buckets, shortly to be emptied, are locked to mark death (2) and stay that way forever.

Yeah I get that. But when I perform a move construction, should I need to create new buckets and copy items from the old map?

Move construction of the map != move construction of the buckets.

From your reply, I understand what I was trying to is not the correct way to implement move construction. Ideally, should I create new buckets and pick items one by one from the old map's buckets and copy it? And while doing it, like you said, I will be marking the new map's buckets as locked (1) and after this process is complete, I just go ahead and mark all buckets of old map as dead (2)? Is that right?

You make new buckets, but move the items.

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2 = this bucket is dead.

Okay. So who takes care of getting rid of the dead buckets?

Old buckets go into a fixed size ring buffer, and get deleted eventually.

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That was my sloppiness on the CI config, sorry, I was running the wrong version of GCC. Fixed now.

So, if "-fsanitize=undefined" a correct flag? I am also getting the same compiler error. Could you let me know which version of gcc should I use?

undefined sanitiser is >= GCC 4.9. You don't need the undefined behaviour sanitiser, though it helps. As the unit tests use OpenMP, you'll need clang 3.7 or higher which hasn't been released yet.

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You need to set the TSAN_OPTIONS environment variable to the suppressions file like this:

export TSAN_OPTIONS="suppressions=tsan.supp history_size=7"

Obviously adjusting the path appropriately. You then run the unittests_sanitise binary. The unit tests should execute very slowly, but hopefully no errors appear.

I will try this out and let you know later.

I see the CI segfaulted last night on this test. I assume it ran out of RAM, so I'll tune that later today. history_size may be too big now. Niall -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/