Author: jtl Date: Fri Apr 6 17:06:22 2018 New Revision: 332117 URL: https://svnweb.freebsd.org/changeset/base/332117
Log: Pat the watchdog less while producing a coredump. Prior to this change, we patted the watchdog approximately once per 4KB page of memory. After this change, we pat the watchdog approximately once per 128MB of memory. On a sample machine, this translated to patting the watchdog approximately every 5.4 seconds, which "seems reasonable". We can choose a different value in the future, if warranted. This has extensive field experience. It is a performance improvement, and has not caused any known problems. Reviewed by: imp, kib Sponsored by: Netflix, Inc. Differential Revision: https://reviews.freebsd.org/D14988 Modified: head/sys/amd64/amd64/minidump_machdep.c Modified: head/sys/amd64/amd64/minidump_machdep.c ============================================================================== --- head/sys/amd64/amd64/minidump_machdep.c Fri Apr 6 17:04:21 2018 (r332116) +++ head/sys/amd64/amd64/minidump_machdep.c Fri Apr 6 17:06:22 2018 (r332117) @@ -62,7 +62,7 @@ static struct kerneldumpheader kdh; /* Handle chunked writes. */ static size_t fragsz; static void *dump_va; -static size_t counter, progress, dumpsize; +static size_t counter, progress, dumpsize, wdog_next; CTASSERT(sizeof(*vm_page_dump) == 8); static int dump_retry_count = 5; @@ -134,6 +134,9 @@ report_progress(size_t progress, size_t dumpsize) } } +/* Pat the watchdog approximately every 128MB of the dump. */ +#define WDOG_DUMP_INTERVAL (128 * 1024 * 1024) + static int blk_write(struct dumperinfo *di, char *ptr, vm_paddr_t pa, size_t sz) { @@ -173,9 +176,14 @@ blk_write(struct dumperinfo *di, char *ptr, vm_paddr_t report_progress(progress, dumpsize); counter &= (1<<24) - 1; } + if (progress <= wdog_next) { + wdog_kern_pat(WD_LASTVAL); + if (wdog_next > WDOG_DUMP_INTERVAL) + wdog_next -= WDOG_DUMP_INTERVAL; + else + wdog_next = 0; + } - wdog_kern_pat(WD_LASTVAL); - if (ptr) { error = dump_append(di, ptr, 0, len); if (error) @@ -313,7 +321,7 @@ minidumpsys(struct dumperinfo *di) } dumpsize += PAGE_SIZE; - progress = dumpsize; + wdog_next = progress = dumpsize; /* Initialize mdhdr */ bzero(&mdhdr, sizeof(mdhdr)); _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
