Re: [PATCH v2 1/5] powerpc/powernv: Re-enable imc trace-mode in kernel
From: maddy <maddy@linux.ibm.com>
Date: 2020-02-06 09:05:32
On 1/21/20 3:47 PM, Anju T Sudhakar wrote:
commit <249fad734a25> ""powerpc/perf: Disable trace_imc pmu" disables IMC(In-Memory Collection) trace-mode in kernel, since frequent mode switching between accumulation mode and trace mode via the spr LDBAR in the hardware can trigger a checkstop(system crash). Patch to re-enable imc-trace mode in kernel. The following patch in this series will address the mode switching issue by implementing a global lock, and will restrict the usage of accumulation and trace-mode at a time.
Reviewed-by: MAdhavan Srinivasan <maddy@linux.ibm.com>
quoted hunk ↗ jump to hunk
Signed-off-by: Anju T Sudhakar <redacted> --- arch/powerpc/platforms/powernv/opal-imc.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-)diff --git a/arch/powerpc/platforms/powernv/opal-imc.c b/arch/powerpc/platforms/powernv/opal-imc.c index 000b350d4060..3b4518f4b643 100644 --- a/arch/powerpc/platforms/powernv/opal-imc.c +++ b/arch/powerpc/platforms/powernv/opal-imc.c@@ -278,14 +278,7 @@ static int opal_imc_counters_probe(struct platform_device *pdev) domain = IMC_DOMAIN_THREAD; break; case IMC_TYPE_TRACE: - /* - * FIXME. Using trace_imc events to monitor application - * or KVM thread performance can cause a checkstop - * (system crash). - * Disable it for now. - */ - pr_info_once("IMC: disabling trace_imc PMU\n"); - domain = -1; + domain = IMC_DOMAIN_TRACE; break; default: pr_warn("IMC Unknown Device type \n");