From 6c685e0cd6143dd7a8b1a9b5631b1bc9c0c4d687 Mon Sep 17 00:00:00 2001 From: Carl Hetherington Date: Fri, 7 Aug 2020 00:11:38 +0200 Subject: [PATCH] Use a much bigger block size when calling fwrite(). Each call to fwrite() writes a few (often around 4) blocks of (I think) directory data to the drive, so if you only fwrite() one block it ends up writing 1 block of "payload" and 4 blocks of "admin". Using bigger blocks makes it faster; an even bigger block than this makes it a little faster still, but not significantly. The extra block writing is seemingly triggered by fwrite() calling ext4_block_cache_write_back(..., 0). A better fix is probably to call this another way, at the end of the file copy. --- src/tools/dcpomatic_disk_writer.cc | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/src/tools/dcpomatic_disk_writer.cc b/src/tools/dcpomatic_disk_writer.cc index a2788e18b..45a5e8c60 100644 --- a/src/tools/dcpomatic_disk_writer.cc +++ b/src/tools/dcpomatic_disk_writer.cc @@ -89,7 +89,8 @@ using boost::optional; #ifdef DCPOMATIC_LINUX static PolkitAuthority* polkit_authority = 0; #endif -static uint64_t const block_size = 4096; +/* Use quite a big block size here, as ext4's fwrite() has quite a bit of overhead */ +static uint64_t const block_size = 4096 * 4096; static Nanomsg* nanomsg = 0; #define SHORT_TIMEOUT 100 @@ -128,7 +129,7 @@ write (boost::filesystem::path from, boost::filesystem::path to, uint64_t& total uint8_t* buffer = new uint8_t[block_size]; Digester digester; - int progress_frequency = 5000; + int progress_frequency = 1; int progress_count = 0; uint64_t remaining = file_size (from); while (remaining > 0) { -- 2.30.2