From mboxrd@z Thu Jan 1 00:00:00 1970 From: compudj@krystal.dyndns.org (Mathieu Desnoyers) Date: Tue, 17 Mar 2009 15:35:32 -0400 Subject: [ltt-dev] cli/sti vs local_cmpxchg and local_add_return In-Reply-To: <20090317.122816.246078801.davem@davemloft.net> References: <20090317013220.GA22474@Krystal> <20090317050135.GB6859@linux.vnet.ibm.com> <20090317160635.GE10092@Krystal> <20090317.122816.246078801.davem@davemloft.net> Message-ID: <20090317193532.GA18503@Krystal> * David Miller (davem at davemloft.net) wrote: > From: Mathieu Desnoyers > Date: Tue, 17 Mar 2009 12:06:35 -0400 > > > But powerpc has non-maskable interrupts, so for less than 4 cycles, I > > think it's better to stay with the local_t variant to be NMI-safe. > > Sparc64 has non-maskable interrupts too btw. > OK, this alone is a strong argument to favor NMI-safe lockless algorithm even if it is a bit slower. We should see what kind of performance impact it has on overall tracing performance to find out if it will make a measurable difference anyway. Mathieu > _______________________________________________ > ltt-dev mailing list > ltt-dev at lists.casi.polymtl.ca > http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev > -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68