kernel/tools/perf/util/util.c, branch master

perf util: Fix NULL check in cpumask_to_cpulist()

2026-01-28T18:18:24Z

The function cpumask_to_cpulist() allocates memory with calloc() and stores the result in 'bm', but then incorrectly checks 'cpumask' for NULL instead of 'bm'. This means that if the allocation fails, the function will dereference a NULL pointer when trying to access 'bm'. Fix the check to test the correct variable 'bm'. Fixes: d40c68a49f69c9bd ("perf header: Support CPU DOMAIN relation info") Reviewed-by: Shrikanth Hegde Signed-off-by: Swapnil Sapkal Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Anubhav Shelat Cc: Chen Yu Cc: Gautham Shenoy Cc: Ian Rogers Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Thomas Falcon Signed-off-by: Arnaldo Carvalho de Melo

perf header: Replace hardcoded max cpus by MAX_NR_CPUS

2026-01-28T18:18:11Z

cpumask and cpulist from cpu-domain header have hardcoded max_cpus value of 1024. Current systems have more cpus than this value. Replace it with MAX_NR_CPUS. Also define a macro to represent domain name length. Fixes: d40c68a49f69c9bd ("perf header: Support CPU DOMAIN relation info") Reported-by: Shrikanth Hegde Reviewed-by: Shrikanth Hegde Signed-off-by: Swapnil Sapkal Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Anubhav Shelat Cc: Chen Yu Cc: Gautham Shenoy Cc: Ian Rogers Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Thomas Falcon Signed-off-by: Arnaldo Carvalho de Melo

perf sched stats: Add support for report subcommand

2026-01-22T15:31:52Z

`perf sched stats record` captures two sets of samples. For workload profile, first set right before workload starts and second set after workload finishes. For the systemwide profile, first set at the beginning of profile and second set on receiving SIGINT signal. Add `perf sched stats report` subcommand that will read both the set of samples, get the diff and render a final report. Final report prints scheduler stat at cpu granularity as well as sched domain granularity. Example usage: # ./perf sched stats record -- true [ perf sched stats: Wrote samples to perf.data ] # perf sched stats report Description ---------------------------------------------------------------------------------------------------- DESC -> Description of the field COUNT -> Value of the field PCT_CHANGE -> Percent change with corresponding base value AVG_JIFFIES -> Avg time in jiffies between two consecutive occurrence of event ---------------------------------------------------------------------------------------------------- Time elapsed (in jiffies) : 1 ---------------------------------------------------------------------------------------------------- CPU: ---------------------------------------------------------------------------------------------------- DESC COUNT PCT_CHANGE ---------------------------------------------------------------------------------------------------- yld_count : 0 array_exp : 0 sched_count : 0 sched_goidle : 0 ( 0.00% ) ttwu_count : 0 ttwu_local : 0 ( 0.00% ) rq_cpu_time : 33525 run_delay : 436 ( 1.30% ) pcount : 0 ---------------------------------------------------------------------------------------------------- CPU: | DOMAIN: SMT ---------------------------------------------------------------------------------------------------- DESC COUNT AVG_JIFFIES ----------------------------------------- ------------------------------------------ busy_lb_count : 0 $ 0.00 $ busy_lb_balanced : 0 $ 0.00 $ busy_lb_failed : 0 $ 0.00 $ busy_lb_imbalance_load : 0 busy_lb_imbalance_util : 0 busy_lb_imbalance_task : 0 busy_lb_imbalance_misfit : 0 busy_lb_gained : 0 busy_lb_hot_gained : 0 busy_lb_nobusyq : 0 $ 0.00 $ busy_lb_nobusyg : 0 $ 0.00 $ *busy_lb_success_count : 0 *busy_lb_avg_pulled : 0.00 ... and so on. Output shows similar data for all the cpus in the system. Co-developed-by: Ravi Bangoria Signed-off-by: Ravi Bangoria Signed-off-by: Swapnil Sapkal Tested-by: Chen Yu Tested-by: James Clark Acked-by: Ian Rogers Acked-by: Peter Zijlstra Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Anubhav Shelat Cc: Ben Gainey Cc: Blake Jones Cc: Chun-Tse Shao Cc: David Vernet Cc: Dmitriy Vyukov Cc: Dr. David Alan Gilbert Cc: Gautham Shenoy Cc: Graham Woodward Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Juri Lelli Cc: K Prateek Nayak Cc: Kan Liang Cc: Leo Yan Cc: Madadi Vineeth Reddy Cc: Mark Rutland Cc: Namhyung Kim Cc: Sandipan Das Cc: Santosh Shukla Cc: Shrikanth Hegde Cc: Steven Rostedt (VMware) Cc: Tejun Heo Cc: Thomas Falcon Cc: Tim Chen Cc: Vincent Guittot Cc: Yang Jihong Cc: Yujie Liu Cc: Zhongqiu Han Signed-off-by: Arnaldo Carvalho de Melo

perf header: Support CPU DOMAIN relation info

2026-01-22T00:55:09Z

The '/proc/schedstat' file gives info about load balancing statistics within a given domain. It also contains the cpu_mask giving information about the sibling cpus and domain names after schedstat version 17. Storing this information in perf header will help tools like `perf sched stats` for better analysis. Signed-off-by: Swapnil Sapkal Tested-by: Chen Yu Acked-by: Ian Rogers Acked-by: Namhyung Kim Acked-by: Peter Zijlstra Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Anubhav Shelat Cc: Ben Gainey Cc: Blake Jones Cc: Chun-Tse Shao Cc: David Vernet Cc: Dmitriy Vyukov Cc: Dr. David Alan Gilbert Cc: Gautham Shenoy Cc: Graham Woodward Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Juri Lelli Cc: K Prateek Nayak Cc: Kan Liang Cc: Leo Yan Cc: Madadi Vineeth Reddy Cc: Mark Rutland Cc: Ravi Bangoria Cc: Sandipan Das Cc: Santosh Shukla Cc: Shrikanth Hegde Cc: Steven Rostedt (VMware) Cc: Tejun Heo Cc: Thomas Falcon Cc: Tim Chen Cc: Vincent Guittot Cc: Yang Jihong Cc: Yujie Liu Cc: Zhongqiu Han Signed-off-by: Arnaldo Carvalho de Melo

perf util: Remove kernel version deadcode

2024-11-16T19:30:39Z

fetch_kernel_version() has been unused since Ian's 2023 commit 3d6dfae889174340 ("perf parse-events: Remove BPF event support") Remove it, and it's helpers. I noticed there are a bunch of kernel-version macros that are also unused nearby. Also remove them. Reviewed-by: Ian Rogers Signed-off-by: Dr. David Alan Gilbert Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20241116155850.113129-1-linux@treblig.org Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Don't set attr.exclude_guest by default

2024-10-22T16:52:11Z

The exclude_guest in the event attribute is to limit profiling in the host environment. But I'm not sure why we want to set it by default cause we don't care about it in most cases and I feel like it just makes new PMU implementation complicated. Of course it's useful for perf kvm command so I added the exclude_GH_default variable to preserve the old behavior for perf kvm and other commands like perf record and stat won't set the exclude bit. This is helpful for AMD IBS case since having exclude_guest bit will clear new feature bit due to the missing feature check logic. $ sysctl kernel.perf_event_paranoid kernel.perf_event_paranoid = 0 $ perf record -W -e ibs_op// -vv true 2>&1 | grep switching switching off PERF_FORMAT_LOST support switching off weight struct support switching off bpf_event switching off ksymbol switching off cloexec flag switching off mmap2 switching off exclude_guest, exclude_host Intestingly, I found it sets the exclude_bit if "u" modifier is used. I don't know why but it's neither intuitive nor consistent. Let's remove the bit there too. Reviewed-by: Ian Rogers Reviewed-by: James Clark Reviewed-by: Ravi Bangoria Acked-by: Kan Liang Cc: James Clark Cc: Atish Patra Cc: Mingwei Zhang Cc: Kajol Jain Cc: Thomas Richter Cc: Palmer Dabbelt Link: https://lore.kernel.org/r/20241016062359.264929-3-namhyung@kernel.org Signed-off-by: Namhyung Kim

perf cap: Tidy up and improve capability testing

2024-08-20T20:53:12Z

Remove dependence on libcap. libcap is only used to query whether a capability is supported, which is just 1 capget system call. If the capget system call fails, fall back on root permission checking. Previously if libcap fails then the permission is assumed not present which may be pessimistic/wrong. Add a used_root out argument to perf_cap__capable to say whether the fall back root check was used. This allows the correct error message, "root" vs "users with the CAP_PERFMON or CAP_SYS_ADMIN capability", to be selected. Tidy uses of perf_cap__capable so that tests aren't repeated if capget isn't supported. Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Athira Rajeev Cc: Changbin Du Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Kan Liang Cc: Leo Yan Cc: Mark Rutland Cc: Namhyung Kim Cc: Oliver Upton Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20240806220614.831914-1-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf list: Add scandirat compatibility function

2024-02-22T17:11:41Z

scandirat is used during the printing of tracepoint events but may be missing from certain libcs. Add a compatibility implementation that uses the symlink of an fd in /proc as a path for the reliably present scandir. Signed-off-by: Ian Rogers Cc: James Clark Cc: Justin Stitt Cc: Bill Wendling Cc: Nick Desaulniers Cc: Yang Jihong Cc: Nathan Chancellor Cc: Kan Liang Cc: Athira Jajeev Cc: llvm@lists.linux.dev Signed-off-by: Namhyung Kim Link: https://lore.kernel.org/r/20240221034155.1500118-3-irogers@google.com

perf util: Move input_name to util

2023-04-10T22:21:31Z

'input_name' is the name of the input perf.data file, it is used by data convert and ui code. Move it to util to make it more consistent with other global state. Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Athira Rajeev Cc: Chengdong Li Cc: Denis Nikitin Cc: Florian Fischer Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: John Garry Cc: Kan Liang Cc: Leo Yan Cc: Mark Rutland Cc: Martin Liška Cc: Mathieu Poirier Cc: Mike Leach Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Raul Silvera Cc: Ravi Bangoria Cc: Rob Herring Cc: Sean Christopherson Cc: Suzuki Poulouse Cc: Will Deacon Cc: Xing Zhengjun Cc: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Link: https://lore.kernel.org/r/20230410162511.3055900-2-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Avoid warning in do_realloc_array_as_needed()

2023-04-04T12:39:56Z

do_realloc_array_as_needed() used memcpy() of zero size with a NULL pointer. Check the size first to avoid sanitize warning. Discovered using EXTRA_CFLAGS="-fsanitize=undefined -fsanitize=address". Reported-by: kernel test robot Signed-off-by: Adrian Hunter Acked-by: Ian Rogers Cc: Jiri Olsa Cc: Namhyung Kim Link: https://lore.kernel.org/oe-lkp/202303061424.6ad43294-yujie.liu@intel.com Link: https://lore.kernel.org/r/20230316194156.8320-2-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo