From 76fc07e3a6cdcb825859d833c83af16a34343f0b Mon Sep 17 00:00:00 2001 From: David Sterba Date: Wed, 2 Nov 2016 13:27:45 +0100 Subject: btrfs-progs: send: increase size of transfer buffer 4K is quite small, increase it to 64K. This reduces number of context switches and calls to read. Kernel sends us about 50K of data per read, so increasing the buffer further does not make any improvement. Example run on tests/cli-tests/004-send-parent-multi-subvol: 4K: - ~800 context switches - ~5000 calls to read 64K: - ~450 context switches - ~500 calls to read Signed-off-by: David Sterba --- cmds-send.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'cmds-send.c') diff --git a/cmds-send.c b/cmds-send.c index 6846b189..0608a106 100644 --- a/cmds-send.c +++ b/cmds-send.c @@ -44,6 +44,8 @@ #include "send.h" #include "send-utils.h" +#define SEND_BUFFER_SIZE (64 * 1024) + /* * Default is 1 for historical reasons, changing may break scripts that expect * the 'At subvol' message. @@ -222,7 +224,7 @@ static void *dump_thread(void *arg_) { int ret; struct btrfs_send *s = (struct btrfs_send*)arg_; - char buf[4096]; + char buf[SEND_BUFFER_SIZE]; int readed; while (1) { -- cgit v1.2.3