- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
It seems like neither VTune nor VTune Amp Xe support sampling intervals of less than 1 ms.
What if I'd like to sample my application twice every millisecond? I.e. Sample every 0.5 ms.
No go, it seems.
This looks like a major oversight, as every other decent profiler (including free CodeAnalyst) supports this simple requirement.
What is the rationale behind this?
What if I'd like to sample my application twice every millisecond? I.e. Sample every 0.5 ms.
No go, it seems.
This looks like a major oversight, as every other decent profiler (including free CodeAnalyst) supports this simple requirement.
What is the rationale behind this?
Link Copied
2 Replies
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
Suppose you have a machine with 2GHz CPU. By setting the SAV=2000000 for CPU clockticks event in the EBS analysis of VTune or Lightweight Hotspot analysis of VTune Amplifier XE, you get 1 sample per ms. This is statistically reasonable sampling rate for most cases. Playing with the SAV towards decrease allows to increase the sampling frequency. But be careful setting too low SAV - the system may hang in oft-recurring hardware interruption handling.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
Note that there are two different types of sampling technology used in VTune Amplifier XE
1. User mode sampling - each sample collects the call stack for each thread - this has a minimum sampling interval of 1ms due to overhead concerns.
2. Hardware-event sampling - Vladimir addressed how to lower the sampling interval in his reply
1. User mode sampling - each sample collects the call stack for each thread - this has a minimum sampling interval of 1ms due to overhead concerns.
2. Hardware-event sampling - Vladimir addressed how to lower the sampling interval in his reply
Reply
Topic Options
- Subscribe to RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Printer Friendly Page