Displaying 20 results from an estimated 27 matches for "tsc_sequenc".
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tsc_sequence
2017 Feb 09
6
[PATCH 2/2] x86/vdso: Add VCLOCK_HVCLOCK vDSO clock read method
...CPAGE
> +static notrace u64 vread_hvclock(int *mode)
> +{
> + const struct ms_hyperv_tsc_page *tsc_pg =
> + (const struct ms_hyperv_tsc_page *)&hvclock_page;
> + u64 sequence, scale, offset, current_tick, cur_tsc;
> +
> + while (1) {
> + sequence = READ_ONCE(tsc_pg->tsc_sequence);
> + if (!sequence)
> + break;
> +
> + scale = READ_ONCE(tsc_pg->tsc_scale);
> + offset = READ_ONCE(tsc_pg->tsc_offset);
> + rdtscll(cur_tsc);
> +
> + current_tick = mul_u64_u64_shr(cur_tsc, scale, 64) + offset;
> +
> + if (READ_ONCE(tsc_pg->tsc_sequ...
2017 Feb 09
6
[PATCH 2/2] x86/vdso: Add VCLOCK_HVCLOCK vDSO clock read method
...CPAGE
> +static notrace u64 vread_hvclock(int *mode)
> +{
> + const struct ms_hyperv_tsc_page *tsc_pg =
> + (const struct ms_hyperv_tsc_page *)&hvclock_page;
> + u64 sequence, scale, offset, current_tick, cur_tsc;
> +
> + while (1) {
> + sequence = READ_ONCE(tsc_pg->tsc_sequence);
> + if (!sequence)
> + break;
> +
> + scale = READ_ONCE(tsc_pg->tsc_scale);
> + offset = READ_ONCE(tsc_pg->tsc_offset);
> + rdtscll(cur_tsc);
> +
> + current_tick = mul_u64_u64_shr(cur_tsc, scale, 64) + offset;
> +
> + if (READ_ONCE(tsc_pg->tsc_sequ...
2017 Feb 09
2
[PATCH 2/2] x86/vdso: Add VCLOCK_HVCLOCK vDSO clock read method
...+ const struct ms_hyperv_tsc_page *tsc_pg =
>> > + (const struct ms_hyperv_tsc_page *)&hvclock_page;
>> > + u64 sequence, scale, offset, current_tick, cur_tsc;
>> > +
>> > + while (1) {
>> > + sequence = READ_ONCE(tsc_pg->tsc_sequence);
>> > + if (!sequence)
>> > + break;
>> > +
>> > + scale = READ_ONCE(tsc_pg->tsc_scale);
>> > + offset = READ_ONCE(tsc_pg->tsc_offset);
>> > + rdtscll(cur_tsc);
>> > +
&g...
2017 Feb 09
2
[PATCH 2/2] x86/vdso: Add VCLOCK_HVCLOCK vDSO clock read method
...+ const struct ms_hyperv_tsc_page *tsc_pg =
>> > + (const struct ms_hyperv_tsc_page *)&hvclock_page;
>> > + u64 sequence, scale, offset, current_tick, cur_tsc;
>> > +
>> > + while (1) {
>> > + sequence = READ_ONCE(tsc_pg->tsc_sequence);
>> > + if (!sequence)
>> > + break;
>> > +
>> > + scale = READ_ONCE(tsc_pg->tsc_scale);
>> > + offset = READ_ONCE(tsc_pg->tsc_offset);
>> > + rdtscll(cur_tsc);
>> > +
&g...
2017 Mar 03
1
[PATCH v3 2/3] x86/hyperv: move TSC reading method to asm/mshyperv.h
...erenceTscSequence again. In case its value has changed
> + * since our first reading we need to discard ReferenceTime and repeat
> + * the whole sequence as the hypervisor was updating the page in
> + * between.
> + */
> + while (1) {
> + sequence = READ_ONCE(tsc_pg->tsc_sequence);
> + if (!sequence)
> + break;
It would be clearer to just return U64_MAX here (and not fall out)
since this is only case here. Also since this failure only occurs if host
clock is not available, probably should be unlikely.
> + /*
> + * Make sure we read sequence before we re...
2017 Mar 03
1
[PATCH v3 2/3] x86/hyperv: move TSC reading method to asm/mshyperv.h
...erenceTscSequence again. In case its value has changed
> + * since our first reading we need to discard ReferenceTime and repeat
> + * the whole sequence as the hypervisor was updating the page in
> + * between.
> + */
> + while (1) {
> + sequence = READ_ONCE(tsc_pg->tsc_sequence);
> + if (!sequence)
> + break;
It would be clearer to just return U64_MAX here (and not fall out)
since this is only case here. Also since this failure only occurs if host
clock is not available, probably should be unlikely.
> + /*
> + * Make sure we read sequence before we re...
2017 Mar 03
0
[PATCH v3 2/3] x86/hyperv: move TSC reading method to asm/mshyperv.h
...@@ -38,39 +38,11 @@ struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
static u64 read_hv_clock_tsc(struct clocksource *arg)
{
- u64 current_tick;
+ u64 current_tick = hv_read_tsc_page(tsc_pg);
+
+ if (current_tick == U64_MAX)
+ rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
- if (tsc_pg->tsc_sequence != 0) {
- /*
- * Use the tsc page to compute the value.
- */
-
- while (1) {
- u64 tmp;
- u32 sequence = tsc_pg->tsc_sequence;
- u64 cur_tsc;
- u64 scale = tsc_pg->tsc_scale;
- s64 offset = tsc_pg->tsc_offset;
-
- rdtscll(cur_tsc);
- /* current_tick = ((cur_tsc *scale)...
2017 Mar 03
4
[PATCH v3 0/3] x86/vdso: Add Hyper-V TSC page clocksource support
Hi,
merge window is about to close so I hope it's OK to make another try here.
Changes since v2:
- Add explicit READ_ONCE() to not rely on 'volatile' [Andy Lutomirski]
- rdtsc() -> rdtsc_ordered() [Andy Lutomirski]
- virt_rmb() -> smp_rmb() [Thomas Gleixner, Andy Lutomirski]
Thomas, Andy, it seems the only blocker for the series was the ambiguity with
TSC page read algorithm.
2017 Mar 03
4
[PATCH v3 0/3] x86/vdso: Add Hyper-V TSC page clocksource support
Hi,
merge window is about to close so I hope it's OK to make another try here.
Changes since v2:
- Add explicit READ_ONCE() to not rely on 'volatile' [Andy Lutomirski]
- rdtsc() -> rdtsc_ordered() [Andy Lutomirski]
- virt_rmb() -> smp_rmb() [Thomas Gleixner, Andy Lutomirski]
Thomas, Andy, it seems the only blocker for the series was the ambiguity with
TSC page read algorithm.
2017 Feb 08
2
[PATCH RFC 2/2] x86/vdso: Add VCLOCK_HVCLOCK vDSO clock read method
...(int *mode)
> +{
> + const struct ms_hyperv_tsc_page *tsc_pg =
> + (const struct ms_hyperv_tsc_page *)&pvclock_page;
> + u64 sequence, scale, offset, current_tick, cur_tsc;
> +
> + while (1) {
> + sequence = READ_ONCE(tsc_pg->tsc_sequence);
> + if (!sequence)
> + break;
> +
> + scale = READ_ONCE(tsc_pg->tsc_scale);
> + offset = READ_ONCE(tsc_pg->tsc_offset);
> + rdtscll(cur_tsc);
> +
> + current_tick = mul64x64_...
2017 Feb 08
2
[PATCH RFC 2/2] x86/vdso: Add VCLOCK_HVCLOCK vDSO clock read method
...(int *mode)
> +{
> + const struct ms_hyperv_tsc_page *tsc_pg =
> + (const struct ms_hyperv_tsc_page *)&pvclock_page;
> + u64 sequence, scale, offset, current_tick, cur_tsc;
> +
> + while (1) {
> + sequence = READ_ONCE(tsc_pg->tsc_sequence);
> + if (!sequence)
> + break;
> +
> + scale = READ_ONCE(tsc_pg->tsc_scale);
> + offset = READ_ONCE(tsc_pg->tsc_offset);
> + rdtscll(cur_tsc);
> +
> + current_tick = mul64x64_...
2017 Feb 10
0
[PATCH 2/2] x86/vdso: Add VCLOCK_HVCLOCK vDSO clock read method
...64 vread_hvclock(int *mode)
>> +{
>> + const struct ms_hyperv_tsc_page *tsc_pg =
>> + (const struct ms_hyperv_tsc_page *)&hvclock_page;
>> + u64 sequence, scale, offset, current_tick, cur_tsc;
>> +
>> + while (1) {
>> + sequence = READ_ONCE(tsc_pg->tsc_sequence);
>> + if (!sequence)
>> + break;
>> +
>> + scale = READ_ONCE(tsc_pg->tsc_scale);
>> + offset = READ_ONCE(tsc_pg->tsc_offset);
>> + rdtscll(cur_tsc);
>> +
>> + current_tick = mul_u64_u64_shr(cur_tsc, scale, 64) + offset;
>> +
>&...
2017 Feb 14
6
[PATCH v2 0/3] x86/vdso: Add Hyper-V TSC page clocksource support
Hi,
while we're still waiting for a definitive ACK from Microsoft that the
algorithm is good for SMP case (as we can't prevent the code in vdso from
migrating between CPUs) I'd like to send v2 with some modifications to keep
the discussion going.
Changes since v1:
- Document the TSC page reading protocol [Thomas Gleixner].
- Separate the TSC page reading code from
2017 Feb 14
6
[PATCH v2 0/3] x86/vdso: Add Hyper-V TSC page clocksource support
Hi,
while we're still waiting for a definitive ACK from Microsoft that the
algorithm is good for SMP case (as we can't prevent the code in vdso from
migrating between CPUs) I'd like to send v2 with some modifications to keep
the discussion going.
Changes since v1:
- Document the TSC page reading protocol [Thomas Gleixner].
- Separate the TSC page reading code from
2017 Feb 08
3
[PATCH RFC 0/2] x86/vdso: Add Hyper-V TSC page clocksource support
Hi,
Hyper-V TSC page clocksource is suitable for vDSO, however, the protocol
defined by the hypervisor is different from VCLOCK_PVCLOCK. I implemented
the required support re-using pvclock_page VVAR. Simple sysbench test shows
the following results:
Before:
# time sysbench --test=memory --max-requests=500000 run
...
real 1m22.618s
user 0m50.193s
sys 0m32.268s
After:
# time sysbench
2017 Feb 08
3
[PATCH RFC 0/2] x86/vdso: Add Hyper-V TSC page clocksource support
Hi,
Hyper-V TSC page clocksource is suitable for vDSO, however, the protocol
defined by the hypervisor is different from VCLOCK_PVCLOCK. I implemented
the required support re-using pvclock_page VVAR. Simple sysbench test shows
the following results:
Before:
# time sysbench --test=memory --max-requests=500000 run
...
real 1m22.618s
user 0m50.193s
sys 0m32.268s
After:
# time sysbench
2017 Feb 09
0
[PATCH 2/2] x86/vdso: Add VCLOCK_HVCLOCK vDSO clock read method
...d_hvclock(int *mode)
> > +{
> > + const struct ms_hyperv_tsc_page *tsc_pg =
> > + (const struct ms_hyperv_tsc_page *)&hvclock_page;
> > + u64 sequence, scale, offset, current_tick, cur_tsc;
> > +
> > + while (1) {
> > + sequence = READ_ONCE(tsc_pg->tsc_sequence);
> > + if (!sequence)
> > + break;
> > +
> > + scale = READ_ONCE(tsc_pg->tsc_scale);
> > + offset = READ_ONCE(tsc_pg->tsc_offset);
> > + rdtscll(cur_tsc);
> > +
> > + current_tick = mul_u64_u64_shr(cur_tsc, scale, 64) + offset;
> >...
2017 Feb 09
0
[PATCH 2/2] x86/vdso: Add VCLOCK_HVCLOCK vDSO clock read method
...ERV_TSCPAGE
> +static notrace u64 vread_hvclock(int *mode) {
> + const struct ms_hyperv_tsc_page *tsc_pg =
> + (const struct ms_hyperv_tsc_page *)&hvclock_page;
> + u64 sequence, scale, offset, current_tick, cur_tsc;
> +
> + while (1) {
> + sequence = READ_ONCE(tsc_pg->tsc_sequence);
> + if (!sequence)
> + break;
> +
> + scale = READ_ONCE(tsc_pg->tsc_scale);
> + offset = READ_ONCE(tsc_pg->tsc_offset);
> + rdtscll(cur_tsc);
> +
> + current_tick = mul_u64_u64_shr(cur_tsc, scale, 64) + offset;
> +
> + if (READ_ONCE(tsc_pg->tsc_sequ...
2017 Feb 09
4
[PATCH 0/2] x86/vdso: Add Hyper-V TSC page clocksource support
Hi,
Hyper-V TSC page clocksource is suitable for vDSO, however, the protocol
defined by the hypervisor is different from VCLOCK_PVCLOCK. Implemented the
required support. Simple sysbench test shows the following results:
Before:
# time sysbench --test=memory --max-requests=500000 run
...
real 1m22.618s
user 0m50.193s
sys 0m32.268s
After:
# time sysbench --test=memory
2017 Feb 09
4
[PATCH 0/2] x86/vdso: Add Hyper-V TSC page clocksource support
Hi,
Hyper-V TSC page clocksource is suitable for vDSO, however, the protocol
defined by the hypervisor is different from VCLOCK_PVCLOCK. Implemented the
required support. Simple sysbench test shows the following results:
Before:
# time sysbench --test=memory --max-requests=500000 run
...
real 1m22.618s
user 0m50.193s
sys 0m32.268s
After:
# time sysbench --test=memory