From ba5bef1bb19b97c88b2e99071ffab067b7f3b9d3 Mon Sep 17 00:00:00 2001 Message-Id: In-Reply-To: References: From: Paolo Bonzini Date: Mon, 9 Dec 2013 14:09:36 +0100 Subject: [PATCH 48/50] qemu-img: dynamically adjust iobuffer size during convert RH-Author: Paolo Bonzini Message-id: <1386598178-11845-51-git-send-email-pbonzini@redhat.com> Patchwork-id: 56087 O-Subject: [RHEL 7.0 qemu-kvm PATCH 50/52] qemu-img: dynamically adjust iobuffer size during convert Bugzilla: 1039557 RH-Acked-by: Jeffrey Cody RH-Acked-by: Fam Zheng RH-Acked-by: Stefan Hajnoczi From: Peter Lieven since the convert process is basically a sync operation it might be benificial in some case to change the hardcoded I/O buffer size to a greater value. This patch increases the I/O buffer size if the output driver advertises an optimal transfer length or discard alignment that is greater than the default buffer size of 2M. Reviewed-by: Paolo Bonzini Signed-off-by: Peter Lieven Signed-off-by: Stefan Hajnoczi (cherry picked from commit f2521c9023067a007d18b844fe7639c1c5b6f2ac) --- qemu-img.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) Signed-off-by: Michal Novotny --- qemu-img.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/qemu-img.c b/qemu-img.c index c81d70a..6890bb1 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -1133,6 +1133,7 @@ static int img_convert(int argc, char **argv) sector_num_next_status = 0; uint64_t bs_sectors; uint8_t * buf = NULL; + size_t bufsectors = IO_BUF_SIZE / BDRV_SECTOR_SIZE; const uint8_t *buf1; BlockDriverInfo bdi; QEMUOptionParameter *param = NULL, *create_options = NULL; @@ -1369,7 +1370,16 @@ static int img_convert(int argc, char **argv) bs_i = 0; bs_offset = 0; bdrv_get_geometry(bs[0], &bs_sectors); - buf = qemu_blockalign(out_bs, IO_BUF_SIZE); + + /* increase bufsectors from the default 4096 (2M) if opt_transfer_length + * or discard_alignment of the out_bs is greater. Limit to 32768 (16MB) + * as maximum. */ + bufsectors = MIN(32768, + MAX(bufsectors, MAX(out_bs->bl.opt_transfer_length, + out_bs->bl.discard_alignment)) + ); + + buf = qemu_blockalign(out_bs, bufsectors * BDRV_SECTOR_SIZE); if (skip_create) { int64_t output_length = bdrv_getlength(out_bs); @@ -1392,7 +1402,7 @@ static int img_convert(int argc, char **argv) goto out; } cluster_size = bdi.cluster_size; - if (cluster_size <= 0 || cluster_size > IO_BUF_SIZE) { + if (cluster_size <= 0 || cluster_size > bufsectors * BDRV_SECTOR_SIZE) { error_report("invalid cluster size"); ret = -1; goto out; @@ -1529,7 +1539,7 @@ static int img_convert(int argc, char **argv) sector_num_next_status = sector_num + n1; } - n = MIN(nb_sectors, IO_BUF_SIZE / 512); + n = MIN(nb_sectors, bufsectors); n = MIN(n, bs_sectors - (sector_num - bs_offset)); n1 = n; -- 1.7.11.7