Questions tagged [perf]
perf is Linux profiling tool for both Linux kernel and underlying hardware (hardware counters).
94 questions
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How to use linux perf in a conda environment
I'm trying to use linux perf program in a conda environment, but the perf program seems to ignore the conda environment. I installed the conda-forge::linux-perf package in my conda environment, but ...
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Can "perf mem" command detect remote memory access on CXL NUMA nodes?
I wonder that if perf mem can detect the remote memory access on CXL NUMA Nodes. I got an AMD-EPYC-9654 server, and CXL Mem is on the Numa Node 2. I run a task on node 0, which accessed the remote ...
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Clarifications on perf_events data collection
Originally posted here on stackoverflow I have never used the perf command before (but I need it), hence I have been reading the (really useful) PerfWiki. The section devoted to Event-based sampling ...
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Failed to run some functions with perf tool in embedded Linux
I am working on an embedded Linux system (kernel-5.19.20), and I tried the perf tool in my SOC, found some functions did NOT work. After run perf record /test/perf_test, I got the perf.data, and perf ...
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How to cross-compile Linux tools/perf for embedded system?
I am working on an embedded Linux system (kernel-5.19.20) on MIPS, and I want to build tools/perf for my system. I want to have libelf feature enabled when cross compile perf, so I firstly cross-...
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perf trace is not available on my machine
I'm on Ubuntu 22.04.5 LTS (GNU/Linux 6.8.0-45-generic x86_64) I installed the perf packages sudo apt install linux-tools-common linux-tools-generic linux-tools-$(uname -r) but when I try to run perf ...
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Cache or save results of perf report
For large files, perf report takes a while. e.g. around 5 minutes for 500G perf.data. Is there a way to dump (certain states of) perf report to a file, or tell perf to cache something that enables ...
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see vdso function with perf report
On my perf report I see a bunch of lines with vdso modules and no function names. I am guessing these are for gettimeofday type calls. But how can I see actual function calls? My perf record command: ...
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INST_RETIRED.ANY no longer works as a performance counter with perf on linux 6.7
With the older kernels INST_RETIRED.ANY (as well as many of the other counters documented in https://perfmon-events.intel.com/ahybrid.htm ) worked as counters for perf. I am now using perf with a 6.7 ...
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A simple memcpy loop with stride of 8-16-32 Bytes, no L1 cache misses, what stalls backend cycles?
I am trying to understand the CPU cache performance in a single producer single consumer queue algorithm, but cannot pinpoint the cause of performance degradation in some cases. The following ...
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Which tools for micro-benchmarking?
I'm not sure which tool to use for micro-benchmarking a C program. I would like to measure both: Memory usage, RSS ( Resident Set Size ) CPU cycles I did use perf record -g and perf script piped ...
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What is futex-default-S?
I can't find more info about futex-default-S Is this a system call? module? or else? https://github.com/torvalds/linux/blob/06dc10eae55b5ceabfef287a7e5f16ceea204aa0/tools/perf/Documentation/perf-lock....
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perf instruction count
so i've been playing with perf and assembly i have the following program: .intel_syntax noprefix .global _start _start: mov cl, 2 mov ebx, 0b101 shr ebx, cl and bl, 1 je do_stuff ...
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Unable to find any information about TLB on my computer or obtain information about hardware counters about TLB
The Ubuntu version I am using is Ubuntu 18.04.6 LTS, and the kernel version is 5.4.0-148 generic. My processor is 12th Gen Intel (R) Core (TM) i7-12700. I would like to know the number of TLB ...
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Security of perf under root access
when I use perf it asked for more permission to be used: You may not have permission to collect stats. I was lazy so I did sudo perf (some short program I created myself) but I later realize you can ...
