Andrew,
Here's an update for perfctr's ppc64 low-level driver
which fixes counter wraparound issues in the driver.
This patch was written by David Gibson; here's his description:
"Problem was that with the conversion of the perfctr state
"start" values from 32 to 64 bits, my typing/sign-extension was no
longer correct, leading to overflows if the hardware counter rolled
over during a run. With this patch the PAPI testcase failures appear
to be back down to the two that we know about."
Signed-off-by: Mikael Pettersson <[email protected]>
drivers/perfctr/ppc64.c | 28 ++++++++++++++--------------
1 files changed, 14 insertions(+), 14 deletions(-)
diff -rupN linux-2.6.12-rc4-mm2/drivers/perfctr/ppc64.c linux-2.6.12-rc4-mm2.perfctr-ppc64-wrap-fix/drivers/perfctr/ppc64.c
--- linux-2.6.12-rc4-mm2/drivers/perfctr/ppc64.c 2005-05-16 18:20:56.000000000 +0200
+++ linux-2.6.12-rc4-mm2.perfctr-ppc64-wrap-fix/drivers/perfctr/ppc64.c 2005-05-17 22:10:22.000000000 +0200
@@ -32,8 +32,8 @@ static DEFINE_PER_CPU(struct per_cpu_cac
/* Structure for counter snapshots, as 32-bit values. */
struct perfctr_low_ctrs {
- unsigned int tsc;
- unsigned int pmc[8];
+ u64 tsc;
+ u32 pmc[8];
};
static unsigned int new_id(void)
@@ -48,7 +48,7 @@ static unsigned int new_id(void)
return id;
}
-static inline unsigned int read_pmc(unsigned int pmc)
+static inline u32 read_pmc(int pmc)
{
switch (pmc) {
case 0:
@@ -81,7 +81,7 @@ static inline unsigned int read_pmc(unsi
}
}
-static inline void write_pmc(int pmc, s32 val)
+static inline void write_pmc(int pmc, u32 val)
{
switch (pmc) {
case 0:
@@ -241,7 +241,7 @@ static void perfctr_cpu_read_counters(st
cstatus = state->user.cstatus;
if (perfctr_cstatus_has_tsc(cstatus))
- ctrs->tsc = mftb() & 0xffffffff;
+ ctrs->tsc = mftb();
for (i = 0; i < perfctr_cstatus_nractrs(cstatus); ++i) {
pmc = state->control.pmc_map[i];
@@ -260,10 +260,10 @@ static void perfctr_cpu_isuspend(struct
cstatus = state->user.cstatus;
nrctrs = perfctr_cstatus_nrctrs(cstatus);
for (i = perfctr_cstatus_nractrs(cstatus); i < nrctrs; ++i) {
- unsigned int pmc = state->control.pmc_map[i];
- unsigned int now = read_pmc(pmc);
+ int pmc = state->control.pmc_map[i];
+ u32 now = read_pmc(pmc);
- state->user.pmc[i].sum += now - state->user.pmc[i].start;
+ state->user.pmc[i].sum += (u32)(now-state->user.pmc[i].start);
state->user.pmc[i].start = now;
}
}
@@ -335,18 +335,18 @@ unsigned int perfctr_cpu_identify_overfl
* about. */
for (i = 0; i < nractrs; ++i) {
int pmc = state->control.pmc_map[i];
- unsigned int val = read_pmc(pmc);
+ u32 val = read_pmc(pmc);
/* For actrs, force a sample if they overflowed */
- if ((int)val < 0) {
- state->user.pmc[i].sum += val - state->user.pmc[i].start;
+ if ((s32)val < 0) {
+ state->user.pmc[i].sum += (u32)(val - state->user.pmc[i].start);
state->user.pmc[i].start = 0;
write_pmc(pmc, 0);
}
}
for (; i < nrctrs; ++i) {
- if ((int)state->user.pmc[i].start < 0) { /* PPC64-specific */
+ if ((s32)state->user.pmc[i].start < 0) { /* PPC64-specific */
int pmc = state->control.pmc_map[i];
/* XXX: "+=" to correct for overshots */
state->user.pmc[i].start = state->control.ireset[pmc];
@@ -550,7 +550,7 @@ void perfctr_cpu_suspend(struct perfctr_
state->user.tsc_sum += now.tsc - state->user.tsc_start;
for (i = 0; i < perfctr_cstatus_nractrs(cstatus); ++i)
- state->user.pmc[i].sum += now.pmc[i] - state->user.pmc[i].start;
+ state->user.pmc[i].sum += (u32)(now.pmc[i]-state->user.pmc[i].start);
}
void perfctr_cpu_resume(struct perfctr_cpu_state *state)
@@ -586,7 +586,7 @@ void perfctr_cpu_sample(struct perfctr_c
}
nractrs = perfctr_cstatus_nractrs(cstatus);
for(i = 0; i < nractrs; ++i) {
- state->user.pmc[i].sum += now.pmc[i] - state->user.pmc[i].start;
+ state->user.pmc[i].sum += (u32)(now.pmc[i]-state->user.pmc[i].start);
state->user.pmc[i].start = now.pmc[i];
}
++state->user.samplecnt;