lkml.org 
[lkml]   [2011]   [Feb]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [patch v2 0/3] OProfile support for System z's hardware sampling
From
Date
Hello Robert,

when do you have a chance do look at my patches?

Looking forward to a positive reply.

Heinz

On Fri, 2011-01-21 at 11:06 +0100, Heinz Graalfs wrote:
> Hello Robert,
>
> I'm resending yesterday's mail because I missed to specify the correct sender information.
>
> This is a re-posting of the patch series originally posted last month:
>
> http://marc.info/?l=linux-s390&m=129285043619973&w=2
>
> Heinz
>
> Changes in
>
> v2:
> - kernel module hwsampler removed, everything is now in oprofile kernel module
> - functions from hwsampler-main.c and smpctl.c merged into arch/s390/oprofile/hwsampler.c
> - functions made static
> - arch/s390/include/asm/hwsampler.h moved to arch/s390/oprofile/hwsampler.h
> - structs have now hws_ prefix
> - config variables changed, HAVE_HWSAMPLER used only
> - original patch 4 (handle_munmap.patch) removed
>
> Description:
>
> So far, OProfile takes samples by using a software interrupt.
> The purpose of this series of patches is to add support for System z hardware sampling to OProfile.
>
> Hardware (HW) sampling is a feature provided by System z processors (z10 and follow ons).
> When sampling, the processor takes samples containing the instruction address, PID, and other information.
> The samples are taken at a programmable rate and stored into a buffer provided by the operating system.
> The sampling process is implemented in hardware and millicode and thus does not affect the operating system
> being oberved, apart from requiring buffer memory that the Linux kernel must provide.
>
> Hardware sampling is available in LPAR mode on 64 BIT processors only.
>
> The overall approach is to replace the software-based sample generation by hardware sampling.
> All required functionality to control the HW sampling mechanism is added to the oprofile kernel module.
> The functions provide support for
> - controlling the sampling hardware,
> - setting up appropriate buffer structures (HW buffers),
> - retrieving sample entries from these buffers.
> Multiple CPUs can be handled.
>
> The samples contain the instruction address, a bit distinguishing between kernel and user space,
> and for user space samples also the PID.
> Instead of taking samples from its own per-CPU buffers, OProfile would rather take samples from the
> HW buffers.
>
> When hardware sampling can be enabled on the current System z processor it will be the new default.
> Switching back to timer based sampling can be established by using
>
> echo 0 > /dev/oprofile/hwsampling/hwsampler
>
> The user space drivers of OProfile also need an extension to control hw sampling by appropriate options.
>
>
> ------------------------------------------------------------------------------
> Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)!
> Finally, a world-class log management solution at an even better price-free!
> Download using promo code Free_Logger_4_Dev2Dev. Offer expires
> February 28th, so secure your free ArcSight Logger TODAY!
> http://p.sf.net/sfu/arcsight-sfd2d
> _______________________________________________
> oprofile-list mailing list
> oprofile-list@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/oprofile-list




\
 
 \ /
  Last update: 2011-02-07 09:25    [W:0.118 / U:1.824 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site