From aaef873b130f4f9c78f8e97b69c235c81b8b8b88 Mon Sep 17 00:00:00 2001 From: Artyom Tarasenko Date: Fri, 12 Apr 2019 23:06:17 +0200 Subject: [PATCH] target/ppc: improve performance of large BAT invalidations MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Performing a complete flush is ~ 100 times faster than flushing 256MiB of 4KiB pages. Set a limit of 1024 pages and perform a complete flush afterwards. This patch significantly speeds up AIX 5.1 and NetBSD-ofppc. Signed-off-by: Artyom Tarasenko Message-Id: <1555103178-21894-4-git-send-email-atar4qemu@gmail.com> Reviewed-by: Hervé Poussineau Signed-off-by: David Gibson --- target/ppc/mmu_helper.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/target/ppc/mmu_helper.c b/target/ppc/mmu_helper.c index d226b3573940..1dbc9acb75ef 100644 --- a/target/ppc/mmu_helper.c +++ b/target/ppc/mmu_helper.c @@ -1820,6 +1820,13 @@ static inline void do_invalidate_BAT(CPUPPCState *env, target_ulong BATu, base = BATu & ~0x0001FFFF; end = base + mask + 0x00020000; + if (((end - base) >> TARGET_PAGE_BITS) > 1024) { + /* Flushing 1024 4K pages is slower than a complete flush */ + LOG_BATS("Flush all BATs\n"); + tlb_flush(CPU(cs)); + LOG_BATS("Flush done\n"); + return; + } LOG_BATS("Flush BAT from " TARGET_FMT_lx " to " TARGET_FMT_lx " (" TARGET_FMT_lx ")\n", base, end, mask); for (page = base; page != end; page += TARGET_PAGE_SIZE) {