From e9b44e8630c68be7554dfdac84e66e55da89d3f0 Mon Sep 17 00:00:00 2001 From: markj Date: Fri, 31 May 2019 18:29:12 +0000 Subject: [PATCH] netdump: Buffer pages to avoid calling netdump_send() on each 4KB write. netdump waits for acknowledgement from the server for each write. When dumping page table pages, we perform many small writes, limiting throughput. Use the netdump client's buffer to buffer small contiguous writes before calling netdump_send() to flush the MAXDUMPPGS-sized buffer. This results in a significant reduction in the time taken to complete a netdump. Submitted by: Sam Gwydir Reviewed by: cem MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D20317 --- sys/netinet/netdump/netdump_client.c | 31 +++++++++++++++++++++++----- 1 file changed, 26 insertions(+), 5 deletions(-) diff --git a/sys/netinet/netdump/netdump_client.c b/sys/netinet/netdump/netdump_client.c index e0d74e368389..262a9d9e9de1 100644 --- a/sys/netinet/netdump/netdump_client.c +++ b/sys/netinet/netdump/netdump_client.c @@ -130,6 +130,9 @@ static struct { union kd_ip ndc_client; union kd_ip ndc_gateway; uint8_t ndc_af; + /* Runtime State */ + off_t nd_tx_off; + size_t nd_buf_len; } nd_conf; #define nd_server nd_conf.ndc_server.in4 #define nd_client nd_conf.ndc_client.in4 @@ -945,6 +948,14 @@ netdump_dumper(void *priv __unused, void *virtual, virtual, (uintmax_t)offset, length); if (virtual == NULL) { + if (nd_conf.nd_buf_len != 0) { + error = netdump_send(NETDUMP_VMCORE, nd_conf.nd_tx_off, nd_buf, + nd_conf.nd_buf_len); + if (error != 0) { + dump_failed = 1; + } + } + if (dump_failed != 0) printf("failed to dump the kernel core\n"); else if (netdump_send(NETDUMP_FINISHED, 0, NULL, 0) != 0) @@ -957,12 +968,22 @@ netdump_dumper(void *priv __unused, void *virtual, if (length > sizeof(nd_buf)) return (ENOSPC); - memmove(nd_buf, virtual, length); - error = netdump_send(NETDUMP_VMCORE, offset, nd_buf, length); - if (error != 0) { - dump_failed = 1; - return (error); + if (nd_conf.nd_buf_len + length > sizeof(nd_buf) || + (nd_conf.nd_buf_len != 0 && nd_conf.nd_tx_off + + nd_conf.nd_buf_len != offset)) { + error = netdump_send(NETDUMP_VMCORE, nd_conf.nd_tx_off, nd_buf, + nd_conf.nd_buf_len); + if (error != 0) { + dump_failed = 1; + return (error); + } + nd_conf.nd_buf_len = 0; + nd_conf.nd_tx_off = offset; } + + memmove(nd_buf + nd_conf.nd_buf_len, virtual, length); + nd_conf.nd_buf_len += length; + return (0); }