Hi, In this patch series we use winkle for offlined cores. I successfully tested the working of this with subcore functionality.
Test scenario was as follows: 1. Set SMT mode to 1, Set subores-per-core to 1 2. Offline a core, in this case cpu 32 (sending it to winkle) 3. Set subcores-per-core to 4 4. Online the core 5. Start a guest (Topology 1 core 2 threads) on a subcore, in this case on cpu 36 This works without any glitch. Thanks, Shreyas On Monday 25 August 2014 11:31 PM, Shreyas B. Prabhu wrote: > Fast sleep is an idle state, where the core and the L1 and L2 > caches are brought down to a threshold voltage. This also means that > the communication between L2 and L3 caches have to be fenced. However > the current P8 chips have a bug wherein this fencing between L2 and > L3 caches get delayed by a cpu cycle. This can delay L3 response to > the other cpus if they request for data during this time. Thus they > would fetch the same data from the memory which could lead to data > corruption if L3 cache is not flushed. > Patch 4 adds support to work around this. > > 'Deep Winkle' is a deeper idle state where core and private L2 are powered > off. While it offers higher power savings, it is at the cost of losing > hypervisor register state and higher latency. > Patch 5-9 adds support for winkle and uses it for offline cpus. > > Patch 1 - Moves parameters required discover idle states to a location > common to both cpuidle driver and powernv core code > Patch 2 - Populates idle state details from device tree > Patch 3 - Enables cpus to run guest after waking up from fastsleep/winkle > > > Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org> > Cc: Paul Mackerras <pau...@samba.org> > Cc: Michael Ellerman <m...@ellerman.id.au> > Cc: Rafael J. Wysocki <r...@rjwysocki.net> > Cc: Srivatsa S. Bhat <sriva...@mit.edu> > Cc: Preeti U. Murthy <pre...@linux.vnet.ibm.com> > Cc: Vaidyanathan Srinivasan <sva...@linux.vnet.ibm.com> > Cc: Rob Herring <robh...@kernel.org> > Cc: Grant Likely <grant.lik...@linaro.org> > Cc: devicet...@vger.kernel.org > Cc: linux...@vger.kernel.org > Cc: linuxppc-...@lists.ozlabs.org > > Preeti U Murthy (2): > cpuidle/powernv: Populate cpuidle state details by querying the > device-tree > powerpc/powernv/cpuidle: Add workaround to enable fastsleep > > Shreyas B. Prabhu (6): > powerpc/kvm/book3s_hv: Enable CPUs to run guest after waking up from > fast-sleep > powerpc/powernv: Add OPAL call to save and restore > powerpc: Adding macro for accessing Thread Switch Control Register > powerpc/powernv: Add winkle infrastructure > powerpc/powernv: Discover and enable winkle > powerpc/powernv: Enter deepest supported idle state in offline > > Srivatsa S. Bhat (1): > powerpc/powernv: Enable Offline CPUs to enter deep idle states > > arch/powerpc/include/asm/machdep.h | 4 + > arch/powerpc/include/asm/opal.h | 10 ++ > arch/powerpc/include/asm/paca.h | 3 + > arch/powerpc/include/asm/ppc-opcode.h | 2 + > arch/powerpc/include/asm/processor.h | 6 +- > arch/powerpc/include/asm/reg.h | 1 + > arch/powerpc/kernel/asm-offsets.c | 1 + > arch/powerpc/kernel/exceptions-64s.S | 37 ++--- > arch/powerpc/kernel/idle.c | 30 ++++ > arch/powerpc/kernel/idle_power7.S | 83 +++++++++- > arch/powerpc/platforms/powernv/opal-wrappers.S | 2 + > arch/powerpc/platforms/powernv/powernv.h | 8 + > arch/powerpc/platforms/powernv/setup.c | 217 > +++++++++++++++++++++++++ > arch/powerpc/platforms/powernv/smp.c | 13 +- > arch/powerpc/platforms/powernv/subcore.c | 15 ++ > drivers/cpuidle/cpuidle-powernv.c | 40 ++++- > 16 files changed, 439 insertions(+), 33 deletions(-) > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
