kernel/tools/perf/bench/mem-functions.c, branch linux-rolling-stable

perf bench mem: Add mmap() workloads

2025-09-19T15:43:59Z

Add two mmap() workloads: one that eagerly populates a region and another that demand faults it in. The intent is to probe the memory subsytem performance incurred by mmap(). $ perf bench mem mmap -s 4gb -p 4kb -l 10 -f populate # Running 'mem/mmap' benchmark: # function 'populate' (Eagerly populated map()) # Copying 4gb bytes ... 1.811691 GB/sec $ perf bench mem mmap -s 4gb -p 2mb -l 10 -f populate # Running 'mem/mmap' benchmark: # function 'populate' (Eagerly populated mmap()) # Copying 4gb bytes ... 12.272017 GB/sec $ perf bench mem mmap -s 4gb -p 1gb -l 10 -f populate # Running 'mem/mmap' benchmark: # function 'populate' (Eagerly populated mmap()) # Copying 4gb bytes ... 17.085927 GB/sec Signed-off-by: Ankur Arora Tested-by: Arnaldo Carvalho de Melo Cc: Andrew Morton Cc: Andy Lutomirski Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Dave Hansen Cc: David Hildenbrand Cc: H. Peter Anvin Cc: Ingo Molnar Cc: Konrad Rzeszutek Wilk Cc: Mateusz Guzik Cc: Matthew Wilcox Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Raghavendra K T Cc: Thomas Gleixner Signed-off-by: Arnaldo Carvalho de Melo

perf bench mem: Refactor mem_options

2025-09-19T15:43:49Z

Split mem benchmark options into common and memset/memcpy specific. Reviewed-by: Namhyung Kim Signed-off-by: Ankur Arora Cc: Andrew Morton Cc: Andy Lutomirski Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Dave Hansen Cc: David Hildenbrand Cc: H. Peter Anvin Cc: Ingo Molnar Cc: Konrad Rzeszutek Wilk Cc: Mateusz Guzik Cc: Matthew Wilcox Cc: Peter Zijlstra Cc: Raghavendra K T Cc: Thomas Gleixner Signed-off-by: Arnaldo Carvalho de Melo

perf bench mem: Allow chunking on a memory region

2025-09-19T15:43:38Z

There can be a significant gap in memset/memcpy performance depending on the size of the region being operated on. With chunk-size=4kb: $ echo madvise > /sys/kernel/mm/transparent_hugepage/enabled $ perf bench mem memset -p 4kb -k 4kb -s 4gb -l 10 -f x86-64-stosq # Running 'mem/memset' benchmark: # function 'x86-64-stosq' (movsq-based memset() in arch/x86/lib/memset_64.S) # Copying 4gb bytes ... 13.011655 GB/sec With chunk-size=1gb: $ echo madvise > /sys/kernel/mm/transparent_hugepage/enabled $ perf bench mem memset -p 4kb -k 1gb -s 4gb -l 10 -f x86-64-stosq # Running 'mem/memset' benchmark: # function 'x86-64-stosq' (movsq-based memset() in arch/x86/lib/memset_64.S) # Copying 4gb bytes ... 21.936355 GB/sec So, allow the user to specify the chunk-size. The default value is identical to the total size of the region, which preserves current behaviour. Reviewed-by: Namhyung Kim Signed-off-by: Ankur Arora Tested-by: Arnaldo Carvalho de Melo Cc: Andrew Morton Cc: Andy Lutomirski Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Dave Hansen Cc: David Hildenbrand Cc: H. Peter Anvin Cc: Ingo Molnar Cc: Konrad Rzeszutek Wilk Cc: Mateusz Guzik Cc: Matthew Wilcox Cc: Peter Zijlstra Cc: Raghavendra K T Cc: Thomas Gleixner Signed-off-by: Arnaldo Carvalho de Melo

perf bench mem: Allow mapping of hugepages

2025-09-19T15:43:26Z

Page sizes that can be selected: 4KB, 2MB, 1GB. Both the reservation and node from which hugepages are allocated from are expected to be addressed by the user. An example of page-size selection: $ perf bench mem memset -s 4gb -p 2mb # Running 'mem/memset' benchmark: # function 'default' (Default memset() provided by glibc) # Copying 4gb bytes ... 14.919194 GB/sec # function 'x86-64-unrolled' (unrolled memset() in arch/x86/lib/memset_64.S) # Copying 4gb bytes ... 11.514503 GB/sec # function 'x86-64-stosq' (movsq-based memset() in arch/x86/lib/memset_64.S) # Copying 4gb bytes ... 12.600568 GB/sec Signed-off-by: Ankur Arora Tested-by: Arnaldo Carvalho de Melo Cc: Andrew Morton Cc: Andy Lutomirski Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Dave Hansen Cc: David Hildenbrand Cc: H. Peter Anvin Cc: Ingo Molnar Cc: Konrad Rzeszutek Wilk Cc: Mateusz Guzik Cc: Matthew Wilcox Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Raghavendra K T Cc: Thomas Gleixner Signed-off-by: Arnaldo Carvalho de Melo

perf bench mem: Switch from zalloc() to mmap()

2025-09-19T15:43:12Z

Using mmap() ensures that the buffer is always aligned at a fixed boundary. Switch to that to remove one source of variability. Since we always want to read/write from the allocated buffers map with pagetables pre-populated. Reviewed-by: Namhyung Kim Signed-off-by: Ankur Arora Cc: Andrew Morton Cc: Andy Lutomirski Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Dave Hansen Cc: David Hildenbrand Cc: H. Peter Anvin Cc: Ingo Molnar Cc: Konrad Rzeszutek Wilk Cc: Mateusz Guzik Cc: Matthew Wilcox Cc: Peter Zijlstra Cc: Raghavendra K T Cc: Thomas Gleixner Signed-off-by: Arnaldo Carvalho de Melo

perf bench mem: Pull out init/fini logic

2025-09-19T15:43:01Z

No functional change. Reviewed-by: Namhyung Kim Signed-off-by: Ankur Arora Cc: Andrew Morton Cc: Andy Lutomirski Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Dave Hansen Cc: David Hildenbrand Cc: H. Peter Anvin Cc: Ingo Molnar Cc: Konrad Rzeszutek Wilk Cc: Mateusz Guzik Cc: Matthew Wilcox Cc: Peter Zijlstra Cc: Raghavendra K T Cc: Thomas Gleixner Signed-off-by: Arnaldo Carvalho de Melo

perf bench mem: Move mem op parameters into a structure

2025-09-19T15:42:50Z

Move benchmark function parameters in struct bench_params. Reviewed-by: Namhyung Kim Signed-off-by: Ankur Arora Cc: Andrew Morton Cc: Andy Lutomirski Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Dave Hansen Cc: David Hildenbrand Cc: H. Peter Anvin Cc: Ingo Molnar Cc: Konrad Rzeszutek Wilk Cc: Mateusz Guzik Cc: Matthew Wilcox Cc: Peter Zijlstra Cc: Raghavendra K T Cc: Thomas Gleixner Link: https://lore.kernel.org/r/20250917152418.4077386-4-ankur.a.arora@oracle.com Signed-off-by: Arnaldo Carvalho de Melo

perf bench mem: Defer type munging of size to float

2025-09-19T15:42:40Z

Do type conversion to double at the point of use. Reviewed-by: Namhyung Kim Signed-off-by: Ankur Arora Cc: Andrew Morton Cc: Andy Lutomirski Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Dave Hansen Cc: David Hildenbrand Cc: H. Peter Anvin Cc: Ingo Molnar Cc: Konrad Rzeszutek Wilk Cc: Mateusz Guzik Cc: Matthew Wilcox Cc: Peter Zijlstra Cc: Raghavendra K T Cc: Thomas Gleixner Link: https://lore.kernel.org/r/20250917152418.4077386-3-ankur.a.arora@oracle.com Signed-off-by: Arnaldo Carvalho de Melo

perf bench mem: Remove repetition around time measurement

2025-09-19T15:42:28Z

We have two copies of each mem benchmark: one using cycles to measure time, the second for gettimeofday(). Unify. Reviewed-by: Namhyung Kim Signed-off-by: Ankur Arora Cc: Andrew Morton Cc: Andy Lutomirski Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Dave Hansen Cc: David Hildenbrand Cc: H. Peter Anvin Cc: Ingo Molnar Cc: Konrad Rzeszutek Wilk Cc: Mateusz Guzik Cc: Matthew Wilcox Cc: Peter Zijlstra Cc: Raghavendra K T Cc: Thomas Gleixner Signed-off-by: Arnaldo Carvalho de Melo

perf bench mem: Always memset source before memcpy

2020-08-13T12:34:26Z

For memcpy, the source pages are memset to zero only when --cycles is used. This leads to wildly different results with or without --cycles, since all sources pages are likely to be mapped to the same zero page without explicit writes. Before this fix: $ export cmd="./perf stat -e LLC-loads -- ./perf bench \ mem memcpy -s 1024MB -l 100 -f default" $ $cmd 2,935,826 LLC-loads 3.821677452 seconds time elapsed $ $cmd --cycles 217,533,436 LLC-loads 8.616725985 seconds time elapsed After this fix: $ $cmd 214,459,686 LLC-loads 8.674301124 seconds time elapsed $ $cmd --cycles 214,758,651 LLC-loads 8.644480006 seconds time elapsed Fixes: 47b5757bac03c338 ("perf bench mem: Move boilerplate memory allocation to the infrastructure") Signed-off-by: Vincent Whitchurch Cc: Alexander Shishkin Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: kernel@axis.com Link: http://lore.kernel.org/lkml/20200810133404.30829-1-vincent.whitchurch@axis.com Signed-off-by: Arnaldo Carvalho de Melo