From 72653ae5303c626ca29fcbcbb8165a894a104adf Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 20 Aug 2020 10:11:17 -0700 Subject: [PATCH] selftests: net: tcp_mmap: Use huge pages in send path There are significant gains using huge pages when available, as shown in [1]. This patch adds mmap_large_buffer() and uses it in client side (tx path of this reference tool) Following patch will use the feature for server side. [1] https://patchwork.ozlabs.org/project/netdev/patch/20200820154359.1806305-1-edumazet@google.com/ Signed-off-by: Eric Dumazet Cc: Arjun Roy Cc: Soheil Hassas Yeganeh Signed-off-by: David S. Miller --- tools/testing/selftests/net/tcp_mmap.c | 29 ++++++++++++++++++++++++++--- 1 file changed, 26 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/net/tcp_mmap.c b/tools/testing/selftests/net/tcp_mmap.c index 59ec0b59f7b7..ca2618f3e7a1 100644 --- a/tools/testing/selftests/net/tcp_mmap.c +++ b/tools/testing/selftests/net/tcp_mmap.c @@ -123,6 +123,28 @@ void hash_zone(void *zone, unsigned int length) #define ALIGN_UP(x, align_to) (((x) + ((align_to)-1)) & ~((align_to)-1)) #define ALIGN_PTR_UP(p, ptr_align_to) ((typeof(p))ALIGN_UP((unsigned long)(p), ptr_align_to)) + +static void *mmap_large_buffer(size_t need, size_t *allocated) +{ + void *buffer; + size_t sz; + + /* Attempt to use huge pages if possible. */ + sz = ALIGN_UP(need, map_align); + buffer = mmap(NULL, sz, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB, -1, 0); + + if (buffer == (void *)-1) { + sz = need; + buffer = mmap(NULL, sz, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if (buffer != (void *)-1) + fprintf(stderr, "MAP_HUGETLB attempt failed, look at /sys/kernel/mm/hugepages for optimal performance\n"); + } + *allocated = sz; + return buffer; +} + void *child_thread(void *arg) { unsigned long total_mmap = 0, total = 0; @@ -351,6 +373,7 @@ int main(int argc, char *argv[]) uint64_t total = 0; char *host = NULL; int fd, c, on = 1; + size_t buffer_sz; char *buffer; int sflg = 0; int mss = 0; @@ -441,8 +464,8 @@ int main(int argc, char *argv[]) } do_accept(fdlisten); } - buffer = mmap(NULL, chunk_size, PROT_READ | PROT_WRITE, - MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + + buffer = mmap_large_buffer(chunk_size, &buffer_sz); if (buffer == (char *)-1) { perror("mmap"); exit(1); @@ -488,6 +511,6 @@ int main(int argc, char *argv[]) total += wr; } close(fd); - munmap(buffer, chunk_size); + munmap(buffer, buffer_sz); return 0; } -- 2.11.0