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[PATCH -tip v2 0/5] kprobes: batch (un)optimization support
- From: Masami Hiramatsu <mhiramat at redhat dot com>
- To: Ingo Molnar <mingo at elte dot hu>, lkml<linux-kernel at vger dot kernel dot org>
- Cc: Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, Ingo Molnar <mingo at elte dot hu>, Jim Keniston <jkenisto at us dot ibm dot com>, Jason Baron <jbaron at redhat dot com>, Mathieu Desnoyers <mathieu dot desnoyers at efficios dot com>, systemtap<systemtap at sources dot redhat dot com>, DLE<dle-develop at lists dot sourceforge dot net>
- Date: Tue, 18 May 2010 16:12:44 -0400
- Subject: [PATCH -tip v2 0/5] kprobes: batch (un)optimization support
Hi,
Here is the 2nd version of batch optimizing patch series.
Since current kprobes jump optimization calls stop_machine() for each
probe, it can make a lot latency noise when (un)registering a lot of
probes (~1000) at once. For example, on 4 core Xeon, 256 probes
optimization takes 770us in average (max 3.3ms).
This patch series introduces batch (un)optimization which modifies
code with just one stop_machine(), and it improves optimization time
to 90us in average (max 330us).
- Introduce text_poke_smp_batch() which modifies multiple
codes with one stop_machine().
- Limit how many probes can be (un)optimized at once.
- Introduce delayed unoptimization for batch processing.
text_poke_smp_batch() also helps Jason's Jump label to reduce
its overhead coming from text_poke_smp().
Changes in v2:
- Add kprobes selftest bugfix patch.
- Add some comments about locks according to Mathieu's comment.
- Allocate working buffers when initializing kprobes, instead of
using static arraies.
- Merge max optimization limit patch into batch optimizing patch.
Thank you,
---
Masami Hiramatsu (5):
kprobes: Support delayed unoptimization
kprobes/x86: Use text_poke_smp_batch
x86: Introduce text_poke_smp_batch() for batch-code modifying
[CLEANUP] kprobes: Remove redundant text_mutex lock in optimize
[BUGFIX] kprobes: Fix selftest to clear flags field for reusing probes
arch/x86/include/asm/alternative.h | 7 +
arch/x86/include/asm/kprobes.h | 4
arch/x86/kernel/alternative.c | 49 +++-
arch/x86/kernel/kprobes.c | 114 +++++++++
include/linux/kprobes.h | 4
kernel/kprobes.c | 442 ++++++++++++++++++++++++------------
kernel/test_kprobes.c | 12 +
7 files changed, 464 insertions(+), 168 deletions(-)
--
Masami Hiramatsu
e-mail: mhiramat@redhat.com