Обсуждение: hyperthreading and pqlib

Hi all.
Has someone encountered a problem using pqlib in a multi-threading application (POSIX or Win32) when the Intel Hyperthreading is enabled? Disabling the hyperthreading option from the bios of the computer all works fine, otherwise the threaded application does freeze
randomically after a while (This behaviour is common to Linux and WIndows version of the multi-threaded application).

Any idea?

Thanks in advance.

Luca.

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luca.ciciriello@email.it wrote:
> Hi all.
> Has someone encountered a problem using pqlib in a multi-threading
> application (POSIX or Win32) when the Intel Hyperthreading is enabled?
> Disabling the hyperthreading option from the bios of the computer all works
> fine, otherwise the threaded application does freeze randomically after a
> while (This behaviour is common to Linux and WIndows version of the
> multi-threaded application).Any idea?Thanks in advance.Luca.

What version of Postgres?  Does the application freeze or the operating
system?  We have not heard similar reports.  We don't actually recommend
hyperthreading usually.

--
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://postgres.enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +

Bruce Momjian <bruce@momjian.us> writes:
> luca.ciciriello@email.it wrote:
>> Has someone encountered a problem using pqlib in a multi-threading
>> application (POSIX or Win32) when the Intel Hyperthreading is enabled?
>> Disabling the hyperthreading option from the bios of the computer all works
>> fine, otherwise the threaded application does freeze randomically after a
>> while (This behaviour is common to Linux and WIndows version of the
>> multi-threaded application).Any idea?Thanks in advance.Luca.

> What version of Postgres?  Does the application freeze or the operating
> system?  We have not heard similar reports.  We don't actually recommend
> hyperthreading usually.

What it sounds like to me is that the multithreaded application has bugs
(race conditions) that happen to be more easily exposed when HT is on,
presumably because it's then possible for more threads to actually execute
concurrently.

If libpq is involved in this at all, it's probably because you're
failing to prevent multiple threads from using the same PGconn object at
the same time.  But it's just as likely that the bug is completely
unrelated to libpq.

Anyway, you're going to need to get out your debugger and see where it's
getting stuck before you can make much progress fixing it.

            regards, tom lane

The Postgres version is 8.2.4 and seems that the operating system is not affected by this application freezing.

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