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In perf's 'mem-mode', one can get access to a whole bunch of details specific to a
particular sample instruction. A bunch of those details relate to the data
address.
One interesting thing you can do with data addresses is to convert them into a unique
cacheline they belong too. Organizing these data cachelines into similar groups and sorting
them can reveal cache contention.
This patch creates an alogorithm based on various sample details that can help group
entries together into data cachelines and allows 'perf report' to sort on it.
The algorithm relies on having proper mmap2 support in the kernel to help determine
if the memory map the data address belongs to is private to a pid or globally shared.
The alogortithm is as follows:
o group cpumodes together
o group entries with discovered maps together
o sort on major, minor, inode and inode generation numbers
o if userspace anon, then sort on pid
o sort on cachelines based on data addresses
The 'dcacheline' sort option in 'perf report' only works in 'mem-mode'.
Sample output:
#
# Samples: 206 of event 'cpu/mem-loads/pp'
# Total weight : 2534
# Sort order : dcacheline,pid
#
# Overhead Samples Data Cacheline Command: Pid
# ........ ............ ...................................................................... ..................
#
13.22% 1 [k] 0xffff88042f08ebc0 swapper: 0
9.27% 1 [k] 0xffff88082e8cea80 swapper: 0
3.59% 2 [k] 0xffffffff819ba180 swapper: 0
0.32% 1 [k] arch_trigger_all_cpu_backtrace_handler_na.23901+0xffffffffffffffe0 swapper: 0
0.32% 1 [k] timekeeper_seq+0xfffffffffffffff8 swapper: 0
Note: Added a '+1' to symlen size in hists__calc_col_len to prevent the next column
from prematurely tabbing over and mis-aligning. Not sure what the problem is.
Signed-off-by: Don Zickus <dzickus@redhat.com>
Link: http://lkml.kernel.org/r/1401208087-181977-8-git-send-email-dzickus@redhat.com
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
311 lines
10 KiB
Plaintext
311 lines
10 KiB
Plaintext
perf-report(1)
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==============
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NAME
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----
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perf-report - Read perf.data (created by perf record) and display the profile
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SYNOPSIS
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--------
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[verse]
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'perf report' [-i <file> | --input=file]
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DESCRIPTION
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-----------
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This command displays the performance counter profile information recorded
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via perf record.
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OPTIONS
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-------
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-i::
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--input=::
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Input file name. (default: perf.data unless stdin is a fifo)
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-v::
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--verbose::
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Be more verbose. (show symbol address, etc)
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-n::
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--show-nr-samples::
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Show the number of samples for each symbol
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--showcpuutilization::
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Show sample percentage for different cpu modes.
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-T::
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--threads::
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Show per-thread event counters
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-c::
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--comms=::
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Only consider symbols in these comms. CSV that understands
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file://filename entries. This option will affect the percentage of
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the overhead column. See --percentage for more info.
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-d::
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--dsos=::
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Only consider symbols in these dsos. CSV that understands
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file://filename entries. This option will affect the percentage of
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the overhead column. See --percentage for more info.
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-S::
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--symbols=::
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Only consider these symbols. CSV that understands
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file://filename entries. This option will affect the percentage of
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the overhead column. See --percentage for more info.
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--symbol-filter=::
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Only show symbols that match (partially) with this filter.
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-U::
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--hide-unresolved::
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Only display entries resolved to a symbol.
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-s::
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--sort=::
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Sort histogram entries by given key(s) - multiple keys can be specified
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in CSV format. Following sort keys are available:
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pid, comm, dso, symbol, parent, cpu, srcline, weight, local_weight.
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Each key has following meaning:
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- comm: command (name) of the task which can be read via /proc/<pid>/comm
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- pid: command and tid of the task
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- dso: name of library or module executed at the time of sample
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- symbol: name of function executed at the time of sample
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- parent: name of function matched to the parent regex filter. Unmatched
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entries are displayed as "[other]".
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- cpu: cpu number the task ran at the time of sample
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- srcline: filename and line number executed at the time of sample. The
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DWARF debugging info must be provided.
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- weight: Event specific weight, e.g. memory latency or transaction
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abort cost. This is the global weight.
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- local_weight: Local weight version of the weight above.
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- transaction: Transaction abort flags.
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- overhead: Overhead percentage of sample
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- overhead_sys: Overhead percentage of sample running in system mode
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- overhead_us: Overhead percentage of sample running in user mode
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- overhead_guest_sys: Overhead percentage of sample running in system mode
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on guest machine
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- overhead_guest_us: Overhead percentage of sample running in user mode on
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guest machine
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- sample: Number of sample
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- period: Raw number of event count of sample
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By default, comm, dso and symbol keys are used.
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(i.e. --sort comm,dso,symbol)
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If --branch-stack option is used, following sort keys are also
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available:
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dso_from, dso_to, symbol_from, symbol_to, mispredict.
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- dso_from: name of library or module branched from
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- dso_to: name of library or module branched to
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- symbol_from: name of function branched from
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- symbol_to: name of function branched to
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- mispredict: "N" for predicted branch, "Y" for mispredicted branch
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- in_tx: branch in TSX transaction
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- abort: TSX transaction abort.
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And default sort keys are changed to comm, dso_from, symbol_from, dso_to
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and symbol_to, see '--branch-stack'.
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-F::
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--fields=::
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Specify output field - multiple keys can be specified in CSV format.
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Following fields are available:
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overhead, overhead_sys, overhead_us, overhead_children, sample and period.
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Also it can contain any sort key(s).
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By default, every sort keys not specified in -F will be appended
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automatically.
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If --mem-mode option is used, following sort keys are also available
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(incompatible with --branch-stack):
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symbol_daddr, dso_daddr, locked, tlb, mem, snoop, dcacheline.
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- symbol_daddr: name of data symbol being executed on at the time of sample
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- dso_daddr: name of library or module containing the data being executed
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on at the time of sample
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- locked: whether the bus was locked at the time of sample
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- tlb: type of tlb access for the data at the time of sample
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- mem: type of memory access for the data at the time of sample
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- snoop: type of snoop (if any) for the data at the time of sample
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- dcacheline: the cacheline the data address is on at the time of sample
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And default sort keys are changed to local_weight, mem, sym, dso,
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symbol_daddr, dso_daddr, snoop, tlb, locked, see '--mem-mode'.
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-p::
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--parent=<regex>::
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A regex filter to identify parent. The parent is a caller of this
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function and searched through the callchain, thus it requires callchain
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information recorded. The pattern is in the exteneded regex format and
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defaults to "\^sys_|^do_page_fault", see '--sort parent'.
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-x::
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--exclude-other::
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Only display entries with parent-match.
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-w::
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--column-widths=<width[,width...]>::
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Force each column width to the provided list, for large terminal
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readability.
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-t::
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--field-separator=::
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Use a special separator character and don't pad with spaces, replacing
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all occurrences of this separator in symbol names (and other output)
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with a '.' character, that thus it's the only non valid separator.
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-D::
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--dump-raw-trace::
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Dump raw trace in ASCII.
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-g [type,min[,limit],order[,key]]::
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--call-graph::
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Display call chains using type, min percent threshold, optional print
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limit and order.
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type can be either:
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- flat: single column, linear exposure of call chains.
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- graph: use a graph tree, displaying absolute overhead rates.
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- fractal: like graph, but displays relative rates. Each branch of
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the tree is considered as a new profiled object. +
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order can be either:
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- callee: callee based call graph.
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- caller: inverted caller based call graph.
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key can be:
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- function: compare on functions
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- address: compare on individual code addresses
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Default: fractal,0.5,callee,function.
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--children::
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Accumulate callchain of children to parent entry so that then can
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show up in the output. The output will have a new "Children" column
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and will be sorted on the data. It requires callchains are recorded.
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--max-stack::
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Set the stack depth limit when parsing the callchain, anything
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beyond the specified depth will be ignored. This is a trade-off
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between information loss and faster processing especially for
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workloads that can have a very long callchain stack.
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Default: 127
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-G::
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--inverted::
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alias for inverted caller based call graph.
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--ignore-callees=<regex>::
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Ignore callees of the function(s) matching the given regex.
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This has the effect of collecting the callers of each such
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function into one place in the call-graph tree.
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--pretty=<key>::
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Pretty printing style. key: normal, raw
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--stdio:: Use the stdio interface.
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--tui:: Use the TUI interface, that is integrated with annotate and allows
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zooming into DSOs or threads, among other features. Use of --tui
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requires a tty, if one is not present, as when piping to other
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commands, the stdio interface is used.
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--gtk:: Use the GTK2 interface.
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-k::
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--vmlinux=<file>::
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vmlinux pathname
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--kallsyms=<file>::
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kallsyms pathname
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-m::
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--modules::
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Load module symbols. WARNING: This should only be used with -k and
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a LIVE kernel.
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-f::
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--force::
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Don't complain, do it.
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--symfs=<directory>::
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Look for files with symbols relative to this directory.
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-C::
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--cpu:: Only report samples for the list of CPUs provided. Multiple CPUs can
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be provided as a comma-separated list with no space: 0,1. Ranges of
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CPUs are specified with -: 0-2. Default is to report samples on all
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CPUs.
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-M::
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--disassembler-style=:: Set disassembler style for objdump.
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--source::
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Interleave source code with assembly code. Enabled by default,
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disable with --no-source.
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--asm-raw::
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Show raw instruction encoding of assembly instructions.
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--show-total-period:: Show a column with the sum of periods.
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-I::
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--show-info::
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Display extended information about the perf.data file. This adds
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information which may be very large and thus may clutter the display.
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It currently includes: cpu and numa topology of the host system.
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-b::
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--branch-stack::
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Use the addresses of sampled taken branches instead of the instruction
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address to build the histograms. To generate meaningful output, the
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perf.data file must have been obtained using perf record -b or
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perf record --branch-filter xxx where xxx is a branch filter option.
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perf report is able to auto-detect whether a perf.data file contains
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branch stacks and it will automatically switch to the branch view mode,
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unless --no-branch-stack is used.
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--objdump=<path>::
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Path to objdump binary.
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--group::
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Show event group information together.
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--demangle::
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Demangle symbol names to human readable form. It's enabled by default,
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disable with --no-demangle.
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--mem-mode::
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Use the data addresses of samples in addition to instruction addresses
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to build the histograms. To generate meaningful output, the perf.data
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file must have been obtained using perf record -d -W and using a
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special event -e cpu/mem-loads/ or -e cpu/mem-stores/. See
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'perf mem' for simpler access.
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--percent-limit::
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Do not show entries which have an overhead under that percent.
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(Default: 0).
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--percentage::
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Determine how to display the overhead percentage of filtered entries.
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Filters can be applied by --comms, --dsos and/or --symbols options and
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Zoom operations on the TUI (thread, dso, etc).
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"relative" means it's relative to filtered entries only so that the
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sum of shown entries will be always 100%. "absolute" means it retains
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the original value before and after the filter is applied.
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--header::
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Show header information in the perf.data file. This includes
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various information like hostname, OS and perf version, cpu/mem
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info, perf command line, event list and so on. Currently only
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--stdio output supports this feature.
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--header-only::
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Show only perf.data header (forces --stdio).
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SEE ALSO
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--------
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linkperf:perf-stat[1], linkperf:perf-annotate[1]
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