Milind Chabbi
32ff77e8cc
perf/core: Implement fast breakpoint modification via _IOC_MODIFY_ATTRIBUTES ...
Problem and motivation: Once a breakpoint perf event (PERF_TYPE_BREAKPOINT)
is created, there is no flexibility to change the breakpoint type
(bp_type), breakpoint address (bp_addr), or breakpoint length (bp_len). The
only option is to close the perf event and configure a new breakpoint
event. This inflexibility has a significant performance overhead. For
example, sampling-based, lightweight performance profilers (and also
concurrency bug detection tools), monitor different addresses for a short
duration using PERF_TYPE_BREAKPOINT and change the address (bp_addr) to
another address or change the kind of breakpoint (bp_type) from "write" to
a "read" or vice-versa or change the length (bp_len) of the address being
monitored. The cost of these modifications is prohibitive since it involves
unmapping the circular buffer associated with the perf event, closing the
perf event, opening another perf event and mmaping another circular buffer.
Solution: The new ioctl flag for perf events,
PERF_EVENT_IOC_MODIFY_ATTRIBUTES, introduced in this patch takes a pointer
to a struct perf_event_attr as an argument to update an old breakpoint
event with new address, type, and size. This facility allows retaining a
previous mmaped perf events ring buffer and avoids having to close and
reopen another perf event.
This patch supports only changing PERF_TYPE_BREAKPOINT event type; future
implementations can extend this feature. The patch replicates some of its
functionality of modify_user_hw_breakpoint() in
kernel/events/hw_breakpoint.c. modify_user_hw_breakpoint cannot be called
directly since perf_event_ctx_lock() is already held in _perf_ioctl().
Evidence: Experiments show that the baseline (not able to modify an already
created breakpoint) costs an order of magnitude (~10x) more than the
suggested optimization (having the ability to dynamically modifying a
configured breakpoint via ioctl). When the breakpoints typically do not
trap, the speedup due to the suggested optimization is ~10x; even when the
breakpoints always trap, the speedup is ~4x due to the suggested
optimization.
Testing: tests posted at
https://github.com/linux-contrib/perf_event_modify_bp demonstrate the
performance significance of this patch. Tests also check the functional
correctness of the patch.
Signed-off-by: Milind Chabbi <chabbi.milind@gmail.com>
[ Using modify_user_hw_breakpoint_check function. ]
[ Reformated PERF_EVENT_IOC_*, so the values are all in one column. ]
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Oleg Nesterov <onestero@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/20180312134548.31532-8-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-13 15:24:02 +01:00
can: dev: Add support for limiting configured bitrate
2018-01-16 15:11:32 +01:00
firmware /meson
The is the bulk of GPIO changes for the v4.16 kernel cycle.
2018-01-31 12:25:27 -08:00
Staging/IIO patches for 4.16-rc1
2018-02-01 09:51:57 -08:00
RTC for 4.16
2018-02-02 14:19:19 -08:00
Second pull request for 4.16 merge window
2018-02-06 11:09:45 -08:00
mmc: slot-gpio: add a helper to check capability of GPIO WP detection
2018-01-18 09:08:56 +01:00
Core changes:
2018-01-29 09:58:36 +01:00
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
2018-01-31 14:31:10 -08:00
arm_pmu: acpi: request IRQs up-front
2018-02-20 11:34:54 +00:00
pinctrl: remove include file from <linux/device.h>
2018-02-03 12:10:09 -08:00
platform-drivers-x86 for v4.16-1
2018-02-06 15:30:52 -08:00
regulator: add PM suspend and resume hooks
2018-01-26 14:43:55 +00:00
Merge branch 'akpm' (patches from Andrew)
2018-02-22 10:45:46 -08:00
ARM: SoC driver updates for 4.16
2018-02-01 16:35:31 -08:00
NFS client bugfixes and latency improvements for Linux 4.16
2018-02-09 14:55:30 -08:00
device property: Constify device_get_match_data()
2018-02-12 10:41:11 +01:00
arm/arm64: smccc: Implement SMCCC v1.1 inline primitive
2018-02-06 22:54:15 +00:00
lockdep: Convert some users to const
2018-01-18 11:56:49 +01:00
block: display the correct diskname for bio
2018-03-01 08:41:25 -07:00
lib: optimize cpumask_next_and()
2018-02-06 18:32:44 -08:00
blkcg: simplify statistic accumulation code
2018-01-16 08:56:36 -07:00
blk-mq: introduce BLK_STS_DEV_RESOURCE
2018-01-30 20:18:28 -07:00
block: fix a typo in comment of BLK_MQ_POLL_STATS_BKTS
2018-02-15 08:27:06 -07:00
bpf: offload: report device information about offloaded maps
2018-01-18 22:54:25 +01:00
for-linus-20180204
2018-02-04 11:16:35 -08:00
build_bug.h: remove BUILD_BUG_ON_NULL()
2018-02-06 18:32:46 -08:00
Merge branches 'clk-remove-asm-clkdev', 'clk-debugfs-fixes', 'clk-renesas' and 'clk-meson' into clk-next
2018-01-26 16:43:32 -08:00
signal: Unify and correct copy_siginfo_from_user32
2018-01-15 17:55:59 -06:00
x86/retpoline: Support retpoline builds with Clang
2018-02-20 11:17:58 +01:00
Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2018-02-26 09:34:21 -08:00
bug.h: work around GCC PR82365 in BUG()
2018-02-21 15:35:43 -08:00
cpufreq: Add and use cpufreq_for_each_{valid_,}entry_idx()
2018-02-08 10:21:39 +01:00
Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm
2018-02-02 09:50:51 -08:00
Merge branches 'pm-cpuidle' and 'pm-opp'
2018-02-15 12:01:53 +01:00
cpumask: Make for_each_cpu_wrap() available on UP as well
2018-02-16 10:40:24 +01:00
kernel/cpuset: current_cpuset_is_being_rebound can be boolean
2018-02-06 18:32:47 -08:00
crash_dump: is_kdump_kernel can be boolean
2018-02-06 18:32:47 -08:00
vfs: factor out helpers d_instantiate_anon() and d_alloc_anon()
2018-01-24 11:25:59 +01:00
delayacct: Account blkio completion on the correct task
2018-01-16 03:29:36 +01:00
dm mpath: delay the retry of a request if the target responded as busy
2018-01-29 13:44:54 -05:00
pinctrl: remove include file from <linux/device.h>
2018-02-03 12:10:09 -08:00
dma-mapping: fix a comment typo
2018-02-12 15:59:08 +00:00
Merge branch 'next-tpm' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
2018-01-31 13:12:31 -08:00
block: Unexport elv_register_queue() and elv_unregister_queue()
2018-01-18 12:54:41 -07:00
net: Extra '_get' in declaration of arch_get_platform_mac_address
2018-02-08 15:13:30 -05:00
f2fs: support inode creation time
2018-01-25 14:10:39 -08:00
fbdev changes for v4.16:
2018-02-07 13:10:43 -08:00
vfs, fdtable: Prevent bounds-check bypass via speculative execution
2018-01-30 21:54:32 +01:00
bpf: make unknown opcode handling more robust
2018-01-26 16:42:05 -08:00
dax: fix vma_is_fsdax() helper
2018-02-26 12:32:42 -08:00
init_task out-of-lining
2018-01-29 09:08:34 -08:00
device property: Constify device_get_match_data()
2018-02-12 10:41:11 +01:00
genhd: Fix BUG in blkdev_open()
2018-02-26 09:48:42 -07:00
include/linux/genl_magic_func.h: remove own BUILD_BUG_ON*() defines
2018-02-06 18:32:46 -08:00
hrtimer: Implement support for softirq based hrtimers
2018-01-16 09:51:22 +01:00
hugetlb, mbind: fall back to default policy if vma is NULL
2018-01-31 17:18:40 -08:00
perf/core: Implement fast breakpoint modification via _IOC_MODIFY_ATTRIBUTES
2018-03-13 15:24:02 +01:00
i2c: add 'set_sda' to bus_recovery_info
2018-01-16 00:04:19 +01:00
idr: Add documentation
2018-02-06 16:41:29 -05:00
devinet_ioctl(): take copyin/copyout to caller
2018-01-24 19:13:45 -05:00
x86/retpoline: Support retpoline builds with Clang
2018-02-20 11:17:58 +01:00
Expand INIT_STRUCT_PID and remove
2018-01-17 11:30:16 +00:00
iommu/vt-d: Add a check for 5-level paging support
2018-01-17 15:02:50 +01:00
kernel/resource: iomem_is_exclusive can be boolean
2018-02-06 18:32:47 -08:00
init_task out-of-lining
2018-01-29 09:08:34 -08:00
iversion: Rename make inode_cmp_iversion{+raw} to inode_eq_iversion{+raw}
2018-02-01 08:15:25 -05:00
jump_label: Explicitly disable jump labels in __init code
2018-02-21 16:54:05 +01:00
kallsyms: let print_ip_sym() print raw addresses
2018-02-06 18:32:45 -08:00
kasan: clean up KASAN_SHADOW_SCALE_SHIFT usage
2018-02-06 18:32:43 -08:00
Merge branch 'akpm' (patches from Andrew)
2018-02-22 10:45:46 -08:00
vfs/proc/kcore, x86/mm/kcore: Fix SMAP fault when dumping vsyscall user page
2018-02-13 09:15:58 +01:00
extable: Make init_kernel_text() global
2018-02-21 16:54:06 +01:00
kvm: fix warning for non-x86 builds
2018-02-24 01:43:47 +01:00
acpi: nfit: add persistent memory control flag for nd_region
2018-02-01 15:01:15 -07:00
Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2018-01-30 10:44:56 -08:00
lib/lockref: __lockref_is_dead can be boolean
2018-02-06 18:32:47 -08:00
mm/memblock: memblock_is_map/region_memory can be boolean
2018-02-06 18:32:47 -08:00
mm: memcontrol: fix NR_WRITEBACK leak in memcg and system stats
2018-02-21 15:35:42 -08:00
libnvdimm for 4.16
2018-02-06 10:41:33 -08:00
x86/mm, mm/hwpoison: Don't unconditionally unmap kernel 1:1 pages
2018-02-13 16:25:06 +01:00
mm: remove reference to PG_buddy
2018-01-31 17:18:38 -08:00
mm, mmu_notifier: annotate mmu notifiers with blockable invalidate callbacks
2018-01-31 17:18:38 -08:00
include/linux/mmzone.h: fix explanation of lower bits in the SPARSEMEM mem_map pointer
2018-01-31 17:18:39 -08:00
kernel/module: module_is_live can be boolean
2018-02-06 18:32:47 -08:00
locking/mutex: Add comment to __mutex_owner() to deter usage
2018-02-21 08:56:40 +01:00
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
2018-01-31 14:31:10 -08:00
net/dim: Fix fixpoint divide exception in net_dim_stats_compare
2018-01-19 14:53:32 -05:00
bpf: fix null pointer deref in bpf_prog_test_run_xdp
2018-02-01 07:43:56 -08:00
netlink: extack: avoid parenthesized string constant warning
2018-01-15 15:15:23 -05:00
nospec: Include <asm/barrier.h> dependency
2018-02-17 08:40:59 +01:00
NTB: Fix UB/bug in ntb_mw_get_align()
2018-01-28 22:17:24 -05:00
nubus: Add support for the driver model
2018-01-16 16:47:29 +01:00
nvme-pci: clean up SMBSZ bit definitions
2018-01-17 17:55:14 +01:00
DeviceTree updates for 4.16:
2018-02-01 10:57:45 -08:00
DeviceTree updates for 4.16:
2018-02-01 10:57:45 -08:00
iommu: Clean up of_iommu_init_fn
2018-01-17 15:25:50 +01:00
PCI: Make of_irq_parse_pci() static
2018-01-25 08:48:20 -06:00
mm: remove PG_highmem description
2018-01-31 17:18:40 -08:00
mm: get 7% more pages in a pagevec
2018-01-31 17:18:37 -08:00
PCI: Remove NULL device handling from PCI DMA API
2018-01-17 18:05:51 -06:00
PCI: Add SPDX GPL-2.0 to replace GPL v2 boilerplate
2018-01-28 15:48:29 -06:00
PCI: Add SPDX GPL-2.0 to replace GPL v2 boilerplate
2018-01-28 15:48:29 -06:00
Merge branch 'pci/spdx' into next
2018-02-01 11:40:07 -06:00
PCI: Add SPDX GPL-2.0 to replace GPL v2 boilerplate
2018-01-28 15:48:29 -06:00
pci-v4.16-changes
2018-02-06 09:59:40 -08:00
PCI: Add SPDX GPL-2.0+ to replace GPL v2 or later boilerplate
2018-01-28 15:49:06 -06:00
wireless-drivers-next patches for 4.16
2018-02-08 15:32:25 -05:00
perf/core: Optimize ctx_sched_out()
2018-03-12 15:28:50 +01:00
mm, dax: introduce pfn_t_special()
2018-01-19 16:50:53 -08:00
phy: add helpers for setting/clearing bits in PHY registers
2018-01-16 12:25:10 -05:00
pipe: reject F_SETPIPE_SZ with size over UINT_MAX
2018-02-06 18:32:47 -08:00
unify {de,}mangle_poll(), get rid of kernel-side POLL...
2018-02-11 14:37:22 -08:00
device property: Constify device_get_match_data()
2018-02-12 10:41:11 +01:00
firmware/psci: Expose SMCCC version through psci_ops
2018-02-06 22:54:11 +00:00
ptr_ring: prevent integer overflow when calculating size
2018-02-11 22:33:22 -05:00
idr: Remove idr_alloc_ext
2018-02-06 16:41:28 -05:00
Char/Misc driver patches for 4.16-rc1
2018-02-01 10:31:17 -08:00
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
2018-01-31 14:31:10 -08:00
- New Drivers
2018-01-29 10:59:24 -08:00
lib/scatterlist: Fix chaining support in sgl_alloc_order()
2018-01-19 12:31:03 -07:00
Merge branch 'akpm' (patches from Andrew)
2018-02-06 22:15:42 -08:00
vfs: do bulk POLL* -> EPOLL* replacement
2018-02-11 14:34:03 -08:00
locking/semaphore: Update the file path in documentation
2018-02-13 15:00:06 +01:00
seq_file: Introduce DEFINE_SHOW_ATTRIBUTE() helper macro
2018-02-07 12:50:21 +02:00
TTY/Staging driver updates for 4.16-rc1
2018-02-01 09:46:00 -08:00
More ACPI updates for v4.16-rc1
2018-02-09 09:44:25 -08:00
shmem: rename functions that are memfd-related
2018-01-31 17:18:39 -08:00
skb_array: use __ptr_ring_empty
2018-01-29 12:02:54 -05:00
skbuff: Fix comment mis-spelling.
2018-02-16 15:52:42 -05:00
lockdep: Convert some users to const
2018-01-18 11:56:49 +01:00
Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2018-01-31 09:25:20 -08:00
x86: hibernate: fix swsusp_arch_resume() prototype
2018-02-07 12:18:23 +01:00
mm, mlock, vmscan: no more skipping pagevecs
2018-02-21 15:35:42 -08:00
mm, page_vma_mapped: Drop faulty pointer arithmetics in check_pte()
2018-01-21 17:44:47 -08:00
pci-v4.16-changes
2018-02-06 09:59:40 -08:00
locking: Introduce sync_core_before_usermode()
2018-02-05 21:34:50 +01:00
pipe, sysctl: remove pipe_proc_fn()
2018-02-06 18:32:47 -08:00
bpf: Adds field bpf_sock_ops_cb_flags to tcp_sock
2018-01-25 16:41:14 -08:00
Merge branch 'perf/urgent' into perf/core, to pick up fixes
2018-02-17 11:39:28 +01:00
tty: fix data race between tty_init_dev and flush of buf
2018-01-23 08:57:37 +01:00
uuid: cleanup <uapi/linux/uuid.h>
2018-02-06 18:32:44 -08:00
Revert "module: Add retpoline tag to VERMAGIC"
2018-01-24 09:00:05 -08:00
mm: remove unused pgdat_reclaimable_pages()
2018-01-31 17:18:37 -08:00
workqueue: Allow retrieval of current task's work struct
2018-02-16 22:24:25 +01:00
zswap: only save zswap header when necessary
2018-01-31 17:18:39 -08:00
