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1. Feature Overview: Feature Id: [71058] a. Name of Feature: [6.2 FEAT] powerpc: re-enable dispatch trace log userspace interface b. Feature Description Since the cpu accounting code uses the hypervisor dispatch trace log now when CONFIG_VIRT_CPU_ACCOUNTING = y, disabled access to it via files in the /sys/kernel/debug/powerpc/dtl/ directory in that case. This restores those files. To do this, we now have a hook that the cpu accounting code will call as it processes each entry from the hypervisor dispatch trace log. The code in dtl.c now uses that to fill up its ring buffer, rather than having the hypervisor fill the ring buffer directly. This also fixes dtl_file_read() to handle overflow conditions a bit better and adds a spinlock to ensure that race conditions (multiple processes opening or reading the file concurrently) are handled correctly. 2. Feature Details: Sponsor: Power Kernel Architectures: ppc64, Arch Specificity: purely arch specific code Affects Kernel Modules: No Delivery Mechanism: Backport Category: kernel Request Type: Kernel - Enhancement from IBM d. Upstream Acceptance: Accepted Sponsor Priority P3 f. Severity: normal IBM Confidential: No Code Contribution: IBM code g. Component Version Target: --- 3. Business Case Any userspace tools that depend on the /sys/kernel/debug/powerpc/dtl interface will not function when CONFIG_VIRT_CPU_ACCOUNTING = y. This enables those tools to function again. This also resolves some bugs with the sysfs interface. 4. Primary contact at Red Hat: John Jarvis, jjarvis 5. Primary contacts at Partner: Project Management Contact: Michael L. Hohnbaum, hbaum.com Technical contact(s): NISHANTH ARAVAMUDAN, aravam.com
Since RHEL 6.1 External Beta has begun, and this bug remains unresolved, it has been rejected as it is not proposed as exception or blocker. Red Hat invites you to ask your support representative to propose this request, if appropriate and relevant, in the next release of Red Hat Enterprise Linux.
------- Comment From nacc.com 2011-04-28 16:32 EDT------- Upstream commit is 872e439a45ed4a4bd499bc55cb0dffa74027f749
------- Comment From hohnbaum.com 2011-04-29 14:16 EDT------- IBM is quitting this feature request as it has been resolved as part of a 6.1 feature: > Upstream commit is 872e439a45ed4a4bd499bc55cb0dffa74027f749 > Argh, it seems this has already been resolved with the patch from BZ 66961 (RH 633515)