41 lines
1.5 KiB
Diff
41 lines
1.5 KiB
Diff
From f85c851986d24df8700ffe447301786fe83819d0 Mon Sep 17 00:00:00 2001
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From: Alexander Graf <agraf@suse.de>
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Date: Tue, 10 Jul 2012 20:40:55 +0200
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Subject: [PATCH] linux-user: Run multi-threaded code on a single core
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Running multi-threaded code can easily expose some of the fundamental
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breakages in QEMU's design. It's just not a well supported scenario.
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So if we pin the whole process to a single host CPU, we guarantee that
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we will never have concurrent memory access actually happen. We can still
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get scheduled away at any time, so it's no complete guarantee, but apparently
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it reduces the odds well enough to get my test cases to pass.
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This gets Java 1.7 working for me again on my test box.
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Signed-off-by: Alexander Graf <agraf@suse.de>
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---
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linux-user/syscall.c | 9 +++++++++
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1 files changed, 9 insertions(+), 0 deletions(-)
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diff --git a/linux-user/syscall.c b/linux-user/syscall.c
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index 46e964b..b0566cd 100644
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--- a/linux-user/syscall.c
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+++ b/linux-user/syscall.c
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@@ -4298,6 +4298,15 @@ static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp,
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if (nptl_flags & CLONE_SETTLS)
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cpu_set_tls (new_env, newtls);
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+ /* agraf: Pin ourselves to a single CPU when running multi-threaded.
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+ This turned out to improve stability for me. */
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+ {
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+ cpu_set_t mask;
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+ CPU_ZERO(&mask);
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+ CPU_SET(0, &mask);
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+ sched_setaffinity(0, sizeof(mask), &mask);
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+ }
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+
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/* Grab a mutex so that thread setup appears atomic. */
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pthread_mutex_lock(&clone_lock);
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