- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
We miss a TSC deadline interrupt after suspend/resume and using the TSC_ADJUST MSR.
Scenario:
1. system suspend (ACPI S3)
2. system resume
3. synchronize TSC across cores via TSC_ADJUST MSR
4. program TSC-Deadline timer with deadline=1
=> interrupt does not trigger and TSC_DEADLINE reads continue to return 1
Note: this problem does not occur always and it requires the following preconditions:
- suspend-resume cycle
- using the TSC_ADJUST MSR instead of writing the TSC MSR directly (adjustments leads to better synchonization of the TSCs)
We can increase the probability of failure by introducing an idle loop between 3 and 4 e.g.,
while (rdtsc < "10s delay") nop;
I would like to know if we are facing a hardware bug. Spec updates regarding missed deadline interrupts with timed MWAIT could be related.
Link Copied
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
What kind of CPU?
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
We saw it on a couple different machines. We ran our detailed experiments on an i7-5775c and we just received our first bug report from the field from an i7-5600u. All sightings we analyzed so far are from Broadwell-family processors.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
There is errata on Xeon E5 series relate to TSC. You might look into specification update for that processor family
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
I am aware of several errata, in particular the one referring to a lost TSC deadline interrupt after a timed-MWAIT. Since suspend&resume and MWAIT trigger similar sleep state transitions I got wary about a potential hardware bug. Only Intel can resolve this, however their own support engineers recommended posting in this forum to get an answer.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
- Subscribe to RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Printer Friendly Page