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kernel-side TODO

  • Rename s/vmtrace/pgtrace/g

  • Support for multi-process tracing instead of by user uid (discuss)

  • Add versioning to "struct pgtrace_entry"! (discuss)

  • Use dcache cookies to transform inode+bdev into path (much easier to work with). At the moment, if files get deleted during the workload you're doomed, having no way to identify deleted inode numbers.

  • Measure the impact of tracing (relayfs transmission at fault/find_get_page paths, capture daemon, pte unmapping).

  • Timing: current kptecleaner unmap period is "HZ/2" (but HZ in practice since timer is jiffy clocked).

  • Alternatives to timer:

    • "active PTE FIFO". This approach is used by S.F.Kaplan's "vmtrace" tool. Have a FIFO of mapped pte's. Clamp it a certain N size, not allowing more than N pte's to be mapped. Requires unmapping at fault path (touch pte flags, flush TLB).

  • SMP support:

    • add CPUID field to entry

    • one kptecleaner thread per CPU. How to synchronize them?

userspace tools TODO

  • Create a Makefile!

  • vmtrace-split currently splits in per "inode+bdev" type only, should work on uid, pid, pwd, etc. From NPTL trace tool:

    • Trace cut : it is possible to work only on a part of the trace selected with a temporal or a numeric criteria.

    • Trace split : it is possible to split the trace into several files to get either one file per process or one file per thread.

    • Trace filtering : it is possible to filter the trace on various criteria such as event name, object name, kind of object or pid.

    • Log levels : it is possible to switch dynamically from a light trace to a richer or full trace.

    • Large volume of traces : the tool handles large trace files (more than 16 Go).

    • Continuous recording : the tool can keep only the last traces of the execution.

  • vmtrace-split opens an unlimited amount of files, it should cap at 1024 open fd's and reuse those on demand.

  • vmtrace-phase: recognize and classify common access patterns.

  • Generate visual information such as avg.IRF histograms, address versus time graphs, etc, etc.

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last edited 2005-11-26 07:09:08 by EugeneTeo