On Tue, 2013-12-10 at 08:39 +0100, Philippe Bergheaud wrote: > All the important PThread locking occurs in GLIBC libpthread.so > > For scaling to large core counts we need to stay out of the kernel and > scheduler as much as possible which implies increasing the spin time in user > mode. For POWER implementations with SMT this implies that user mode needs to > manage SMT priority for spinning and active (in the critical region) threads. > > Libpthread must be able to raise and lower the the SMT priority versus the > default to be effective. > > This lowers the default kernel thread priority from medium to medium-low.
Hi Philippe, It would be nice if you could make an assertion about what the state of HMT handling should be once your patch is applied. I think it's: * The kernel should use HMT_MEDIUM_LOW as it's "default" priority * The kernel should use HMT_LOW as it's "low" priority Which would imply: * The kernel should not use HMT_MEDIUM anywhere .. * Nor should it use any of the other higher HMT modes. Do you agree? The reason I ask is I still see HMT_MEDIUM used in a few places, and it's not clear to me if that is correct. cheers _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
