forked from Minki/linux
8f62242246
Add two generic hardware events: front-end and back-end stalled cycles. These events measure conditions when the CPU is executing code but its capabilities are not fully utilized. Understanding such situations and analyzing them is an important sub-task of code optimization workflows. Both events limit performance: most front end stalls tend to be caused by branch misprediction or instruction fetch cachemisses, backend stalls can be caused by various resource shortages or inefficient instruction scheduling. Front-end stalls are the more important ones: code cannot run fast if the instruction stream is not being kept up. An over-utilized back-end can cause front-end stalls and thus has to be kept an eye on as well. The exact composition is very program logic and instruction mix dependent. We use the terms 'stall', 'front-end' and 'back-end' loosely and try to use the best available events from specific CPUs that approximate these concepts. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/n/tip-7y40wib8n000io7hjpn1dsrm@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu> |
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| boot | ||
| configs | ||
| crypto | ||
| ia32 | ||
| include/asm | ||
| kernel | ||
| kvm | ||
| lguest | ||
| lib | ||
| math-emu | ||
| mm | ||
| oprofile | ||
| pci | ||
| platform | ||
| power | ||
| tools | ||
| vdso | ||
| video | ||
| xen | ||
| .gitignore | ||
| Kbuild | ||
| Kconfig | ||
| Kconfig.cpu | ||
| Kconfig.debug | ||
| Makefile | ||
| Makefile_32.cpu | ||