Re: Speed up Clog Access by increasing CLOG buffers

On 09/06/2016 04:49 AM, Amit Kapila wrote:
> On Mon, Sep 5, 2016 at 11:34 PM, Tomas Vondra
> <tomas(dot)vondra(at)2ndquadrant(dot)com> wrote:
>>
>>
>> On 09/05/2016 06:03 AM, Amit Kapila wrote:
>>> So, in short we have to compare three
>>> approaches here.
>>>
>>> 1) Group mode to reduce CLOGControlLock contention
>>> 2) Use granular locking model
>>> 3) Use atomic operations
>>>
>>> For approach-1, you can use patch [1]. For approach-2, you can use
>>> 0001-Improve-64bit-atomics-support patch[2] and the patch attached
>>> with this mail. For approach-3, you can use
>>> 0001-Improve-64bit-atomics-support patch[2] and the patch attached
>>> with this mail by commenting USE_CONTENT_LOCK. If the third doesn't
>>> work for you then for now we can compare approach-1 and approach-2.
>>>
>>
>> OK, I can compile all three cases - but onl with gcc 4.7 or newer. Sadly
>> the 4-socket 64-core machine runs Debian Jessie with just gcc 4.6 and my
>> attempts to update to a newer version were unsuccessful so far.
>>
>
> So which all patches your are able to compile on 4-socket m/c? I
> think it is better to measure the performance on bigger machine.

Oh, sorry - I forgot to mention that only the last test (with
USE_CONTENT_LOCK commented out) fails to compile, because the functions
for atomics were added in gcc-4.7.

regards

--
Tomas Vondra http://www.2ndQuadrant.com
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