| Message ID | 20220506061015.43916-1-kjain@linux.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [1/2] powerpc/perf: Fix the threshold compare group constraint for power10 | expand |
> On 06-May-2022, at 11:40 AM, Kajol Jain <kjain@linux.ibm.com> wrote: > > Thresh compare bits for a event is used to program thresh compare > field in Monitor Mode Control Register A (MMCRA: 8-18 bits for power10). > When scheduling events as a group, all events in that group should > match value in threshold bits. Otherwise event open for the sibling > events should fail. But in the current code, incase thresh compare bits are > not valid, we are not failing in group_constraint function which can result > in invalid group schduling. > > Fix the issue by returning -1 incase event is threshold and threshold > compare value is not valid in group_constraint function. > > Patch also fixes the p10_thresh_cmp_val function to return -1, > incase threshold bits are not valid and changes corresponding check in > is_thresh_cmp_valid function to return false only when the thresh_cmp > value is less then 0. > > Thresh control bits in the event code is used to program thresh_ctl > field in Monitor Mode Control Register A (MMCRA: 48-55). In below example, > the scheduling of group events PM_MRK_INST_CMPL (3534401e0) and > PM_THRESH_MET (34340101ec) is expected to fail as both event > request different thresh control bits. > > Result before the patch changes: > > [command]# perf stat -e "{r35340401e0,r34340101ec}" sleep 1 > > Performance counter stats for 'sleep 1': > > 8,482 r35340401e0 > 0 r34340101ec > > 1.001474838 seconds time elapsed > > 0.001145000 seconds user > 0.000000000 seconds sys > > Result after the patch changes: > > [command]# perf stat -e "{r35340401e0,r34340101ec}" sleep 1 > > Performance counter stats for 'sleep 1': > > <not counted> r35340401e0 > <not supported> r34340101ec > > 1.001499607 seconds time elapsed > > 0.000204000 seconds user > 0.000760000 seconds sys > > Fixes: 82d2c16b350f7 ("powerpc/perf: Adds support for programming > of Thresholding in P10") > Signed-off-by: Kajol Jain <kjain@linux.ibm.com> Reviewed-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com> Thanks Athira > --- > arch/powerpc/perf/isa207-common.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/arch/powerpc/perf/isa207-common.c b/arch/powerpc/perf/isa207-common.c > index a74d382ecbb7..013b06af6fe6 100644 > --- a/arch/powerpc/perf/isa207-common.c > +++ b/arch/powerpc/perf/isa207-common.c > @@ -108,7 +108,7 @@ static void mmcra_sdar_mode(u64 event, unsigned long *mmcra) > *mmcra |= MMCRA_SDAR_MODE_TLB; > } > > -static u64 p10_thresh_cmp_val(u64 value) > +static int p10_thresh_cmp_val(u64 value) > { > int exp = 0; > u64 result = value; > @@ -139,7 +139,7 @@ static u64 p10_thresh_cmp_val(u64 value) > * exponent is also zero. > */ > if (!(value & 0xC0) && exp) > - result = 0; > + result = -1; > else > result = (exp << 8) | value; > } > @@ -187,7 +187,7 @@ static bool is_thresh_cmp_valid(u64 event) > unsigned int cmp, exp; > > if (cpu_has_feature(CPU_FTR_ARCH_31)) > - return p10_thresh_cmp_val(event) != 0; > + return p10_thresh_cmp_val(event) >= 0; > > /* > * Check the mantissa upper two bits are not zero, unless the > @@ -502,7 +502,8 @@ int isa207_get_constraint(u64 event, unsigned long *maskp, unsigned long *valp, > value |= CNST_THRESH_CTL_SEL_VAL(event >> EVENT_THRESH_SHIFT); > mask |= p10_CNST_THRESH_CMP_MASK; > value |= p10_CNST_THRESH_CMP_VAL(p10_thresh_cmp_val(event_config1)); > - } > + } else if (event_is_threshold(event)) > + return -1; > } else if (cpu_has_feature(CPU_FTR_ARCH_300)) { > if (event_is_threshold(event) && is_thresh_cmp_valid(event)) { > mask |= CNST_THRESH_MASK; > -- > 2.31.1 >
On Fri, 6 May 2022 11:40:14 +0530, Kajol Jain wrote: > Thresh compare bits for a event is used to program thresh compare > field in Monitor Mode Control Register A (MMCRA: 8-18 bits for power10). > When scheduling events as a group, all events in that group should > match value in threshold bits. Otherwise event open for the sibling > events should fail. But in the current code, incase thresh compare bits are > not valid, we are not failing in group_constraint function which can result > in invalid group schduling. > > [...] Applied to powerpc/next. [1/2] powerpc/perf: Fix the threshold compare group constraint for power10 https://git.kernel.org/powerpc/c/505d31650ba96d6032313480fdb566d289a4698c [2/2] powerpc/perf: Fix the threshold compare group constraint for power9 https://git.kernel.org/powerpc/c/ab0cc6bbf0c812731c703ec757fcc3fc3a457a34 cheers
diff --git a/arch/powerpc/perf/isa207-common.c b/arch/powerpc/perf/isa207-common.c index a74d382ecbb7..013b06af6fe6 100644 --- a/arch/powerpc/perf/isa207-common.c +++ b/arch/powerpc/perf/isa207-common.c @@ -108,7 +108,7 @@ static void mmcra_sdar_mode(u64 event, unsigned long *mmcra) *mmcra |= MMCRA_SDAR_MODE_TLB; } -static u64 p10_thresh_cmp_val(u64 value) +static int p10_thresh_cmp_val(u64 value) { int exp = 0; u64 result = value; @@ -139,7 +139,7 @@ static u64 p10_thresh_cmp_val(u64 value) * exponent is also zero. */ if (!(value & 0xC0) && exp) - result = 0; + result = -1; else result = (exp << 8) | value; } @@ -187,7 +187,7 @@ static bool is_thresh_cmp_valid(u64 event) unsigned int cmp, exp; if (cpu_has_feature(CPU_FTR_ARCH_31)) - return p10_thresh_cmp_val(event) != 0; + return p10_thresh_cmp_val(event) >= 0; /* * Check the mantissa upper two bits are not zero, unless the @@ -502,7 +502,8 @@ int isa207_get_constraint(u64 event, unsigned long *maskp, unsigned long *valp, value |= CNST_THRESH_CTL_SEL_VAL(event >> EVENT_THRESH_SHIFT); mask |= p10_CNST_THRESH_CMP_MASK; value |= p10_CNST_THRESH_CMP_VAL(p10_thresh_cmp_val(event_config1)); - } + } else if (event_is_threshold(event)) + return -1; } else if (cpu_has_feature(CPU_FTR_ARCH_300)) { if (event_is_threshold(event) && is_thresh_cmp_valid(event)) { mask |= CNST_THRESH_MASK;
Thresh compare bits for a event is used to program thresh compare field in Monitor Mode Control Register A (MMCRA: 8-18 bits for power10). When scheduling events as a group, all events in that group should match value in threshold bits. Otherwise event open for the sibling events should fail. But in the current code, incase thresh compare bits are not valid, we are not failing in group_constraint function which can result in invalid group schduling. Fix the issue by returning -1 incase event is threshold and threshold compare value is not valid in group_constraint function. Patch also fixes the p10_thresh_cmp_val function to return -1, incase threshold bits are not valid and changes corresponding check in is_thresh_cmp_valid function to return false only when the thresh_cmp value is less then 0. Thresh control bits in the event code is used to program thresh_ctl field in Monitor Mode Control Register A (MMCRA: 48-55). In below example, the scheduling of group events PM_MRK_INST_CMPL (3534401e0) and PM_THRESH_MET (34340101ec) is expected to fail as both event request different thresh control bits. Result before the patch changes: [command]# perf stat -e "{r35340401e0,r34340101ec}" sleep 1 Performance counter stats for 'sleep 1': 8,482 r35340401e0 0 r34340101ec 1.001474838 seconds time elapsed 0.001145000 seconds user 0.000000000 seconds sys Result after the patch changes: [command]# perf stat -e "{r35340401e0,r34340101ec}" sleep 1 Performance counter stats for 'sleep 1': <not counted> r35340401e0 <not supported> r34340101ec 1.001499607 seconds time elapsed 0.000204000 seconds user 0.000760000 seconds sys Fixes: 82d2c16b350f7 ("powerpc/perf: Adds support for programming of Thresholding in P10") Signed-off-by: Kajol Jain <kjain@linux.ibm.com> --- arch/powerpc/perf/isa207-common.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)