Em Fri, Sep 12, 2014 at 10:37:39AM -0700, David Ahern escreveu: > On 9/12/14, 4:48 AM, Pawel Moll wrote: > >This patch adds a PERF_COUNT_SW_MARKER event type, which > >can be requested by user and a PERF_EVENT_IOC_MARKER > >ioctl command which will inject an event of said type into > >the perf buffer. The ioctl can take a zero-terminated > >string argument, similar to tracing_marker in ftrace, > >which will be kept in the "raw" field of the sample. > > > >The main use case for this is synchronisation of > >performance data generated in user space with the perf > >stream coming from the kernel. For example, the marker > >can be inserted by a JIT engine after it generated > >portion of the code, but before the code is executed > >for the first time, allowing the post-processor to > >pick the correct debugging information. Other example > >is a system profiling tool taking data from other > >sources than just perf, which generates a marker > >at the beginning at at the end of the session > >(also possibly periodically during the session) to > >synchronise kernel timestamps with clock values > >obtained in userspace (gtod or raw_monotonic). > > Seems really similar to what I proposed in the past: > > https://lkml.org/lkml/2011/2/27/159 > > Which was rejected. I took a look at that thread, but just barely, emphasis on that. Injecting something from userspace, a la ftrace, seems to be something, as tglx mentioned, "buried" in that patchset. - Arnaldo -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
