<div dir="ltr">Hi Mikael,<div>Awesome work, I'll give the patch a try this week.</div><div><br></div><div>Thanks,</div><div>LP</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Feb 23, 2015 at 6:30 AM, Mikael Pettersson <span dir="ltr"><<a href="mailto:mikpelinux@gmail.com" target="_blank">mikpelinux@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="HOEnZb"><div class="h5">Louis-Philippe Gauthier writes:<br>
> Hi Sverker,<br>
> That's not a bad idea, I'll try that approach!<br>
><br>
> Thanks,<br>
> LP<br>
><br>
> On Thu, Jan 15, 2015 at 12:27 AM, Sverker Eriksson <<br>
> <a href="mailto:sverker.eriksson@ericsson.com">sverker.eriksson@ericsson.com</a>> wrote:<br>
><br>
> > One quite simple improvement is to change the hipe_mfait_lock to be a<br>
> > read-write mutex (erts_smp_rwmtx_t).<br>
> > And then do read-lock at lookup and exclusive write-lock only when<br>
> > inserting a new entry in the table.<br>
> ><br>
> > I don't think that requires much knowledge about the VM to pull off ;-) .<br>
> ><br>
> > /Sverker, Erlang/OTP<br>
> ><br>
> ><br>
> ><br>
> ><br>
> > On 01/14/2015 12:34 AM, Louis-Philippe Gauthier wrote:<br>
> ><br>
> > Hi erlang-bugs,<br>
> > I couple of months ago I tried running our full application using HiPE. I<br>
> > ran into several issues, some manageable, some not... The most problematic<br>
> > issue was due to locking, specifically, the hipe_mfait_lock (you can see<br>
> > the lock counter output in the gist bellow).<br>
> > <a href="https://gist.github.com/lpgauth/2b3220f4bceeed6f62d0" target="_blank">https://gist.github.com/lpgauth/2b3220f4bceeed6f62d0</a><br>
> ><br>
> > Looking at the code it's obvious that this is a known problem... the<br>
> > following comment was added when the lock was added in 2010.<br>
> ><br>
> > "XXX: Redesign apply et al to avoid those updates."<a href="https://github.com/erlang/otp/blob/maint/erts/emulator/hipe/hipe_bif0.c#L1218" target="_blank">https://github.com/erlang/otp/blob/maint/erts/emulator/hipe/hipe_bif0.c#L1218</a><br>
> ><br>
> > Unfortunately, I'm don't know the runtime enough to start patching it... so<br>
> > instead I'm reporting it.<br>
<br>
</div></div>Please try the attached patch (against 17.4, should apply to older<br>
versions too by I haven't checked), and let me know if it makes a<br>
noticeable improvement to your use case.<br>
<br>
Run-time apply:s now do their lookups using a shared read-lock, and<br>
only if their lookups fail do they re-lock with an exclusive write-lock<br>
in order to insert new data. Module loading functions always take<br>
exclusive locks, which matches the current behaviour.<br>
<span class="HOEnZb"><font color="#888888"><br>
/Mikael<br>
<br>
</font></span><br>--- otp_src_17.4/erts/emulator/hipe/hipe_bif0.c.~1~ 2014-12-09 21:11:07.000000000 +0100<br>
+++ otp_src_17.4/erts/emulator/hipe/hipe_bif0.c 2015-02-22 21:32:55.361884741 +0100<br>
@@ -1217,22 +1217,32 @@ static struct {<br>
* they create a new stub for the mfa, which forces locking.<br>
* XXX: Redesign apply et al to avoid those updates.<br>
*/<br>
- erts_smp_mtx_t lock;<br>
+ erts_smp_rwmtx_t lock;<br>
} hipe_mfa_info_table;<br>
<br>
static inline void hipe_mfa_info_table_init_lock(void)<br>
{<br>
- erts_smp_mtx_init(&hipe_mfa_info_table.lock, "hipe_mfait_lock");<br>
+ erts_smp_rwmtx_init(&hipe_mfa_info_table.lock, "hipe_mfait_lock");<br>
}<br>
<br>
-static inline void hipe_mfa_info_table_lock(void)<br>
+static inline void hipe_mfa_info_table_rlock(void)<br>
{<br>
- erts_smp_mtx_lock(&hipe_mfa_info_table.lock);<br>
+ erts_smp_rwmtx_rlock(&hipe_mfa_info_table.lock);<br>
}<br>
<br>
-static inline void hipe_mfa_info_table_unlock(void)<br>
+static inline void hipe_mfa_info_table_runlock(void)<br>
{<br>
- erts_smp_mtx_unlock(&hipe_mfa_info_table.lock);<br>
+ erts_smp_rwmtx_runlock(&hipe_mfa_info_table.lock);<br>
+}<br>
+<br>
+static inline void hipe_mfa_info_table_rwlock(void)<br>
+{<br>
+ erts_smp_rwmtx_rwlock(&hipe_mfa_info_table.lock);<br>
+}<br>
+<br>
+static inline void hipe_mfa_info_table_rwunlock(void)<br>
+{<br>
+ erts_smp_rwmtx_rwunlock(&hipe_mfa_info_table.lock);<br>
}<br>
<br>
#define HIPE_MFA_HASH(M,F,A) ((M) * (F) + (A))<br>
@@ -1333,6 +1343,7 @@ void *hipe_mfa_find_na(Eterm m, Eterm f,<br>
}<br>
#endif<br>
<br>
+/* PRE: called with write lock held */<br>
static struct hipe_mfa_info *hipe_mfa_info_table_put_locked(Eterm m, Eterm f, unsigned int arity)<br>
{<br>
unsigned long h;<br>
@@ -1362,7 +1373,7 @@ static void hipe_mfa_set_na(Eterm m, Ete<br>
{<br>
struct hipe_mfa_info *p;<br>
<br>
- hipe_mfa_info_table_lock();<br>
+ hipe_mfa_info_table_rwlock();<br>
p = hipe_mfa_info_table_put_locked(m, f, arity);<br>
#ifdef DEBUG_LINKER<br>
printf("%s: ", __FUNCTION__);<br>
@@ -1372,7 +1383,7 @@ static void hipe_mfa_set_na(Eterm m, Ete<br>
p->local_address = address;<br>
if (is_exported)<br>
p->remote_address = address;<br>
- hipe_mfa_info_table_unlock();<br>
+ hipe_mfa_info_table_rwunlock();<br>
}<br>
<br>
#if defined(__powerpc__) || defined(__ppc__) || defined(__powerpc64__) || defined(__arm__)<br>
@@ -1381,10 +1392,10 @@ void *hipe_mfa_get_trampoline(Eterm m, E<br>
struct hipe_mfa_info *p;<br>
void *trampoline;<br>
<br>
- hipe_mfa_info_table_lock();<br>
- p = hipe_mfa_info_table_put_locked(m, f, arity);<br>
- trampoline = p->trampoline;<br>
- hipe_mfa_info_table_unlock();<br>
+ hipe_mfa_info_table_rlock();<br>
+ p = hipe_mfa_info_table_get_locked(m, f, arity);<br>
+ trampoline = p ? p->trampoline : NULL;<br>
+ hipe_mfa_info_table_runlock();<br>
return trampoline;<br>
}<br>
<br>
@@ -1392,10 +1403,10 @@ void hipe_mfa_set_trampoline(Eterm m, Et<br>
{<br>
struct hipe_mfa_info *p;<br>
<br>
- hipe_mfa_info_table_lock();<br>
+ hipe_mfa_info_table_rwlock();<br>
p = hipe_mfa_info_table_put_locked(m, f, arity);<br>
p->trampoline = trampoline;<br>
- hipe_mfa_info_table_unlock();<br>
+ hipe_mfa_info_table_rwunlock();<br>
}<br>
#endif<br>
<br>
@@ -1426,7 +1437,7 @@ BIF_RETTYPE hipe_bifs_invalidate_funinfo<br>
struct mfa mfa;<br>
struct hipe_mfa_info *p;<br>
<br>
- hipe_mfa_info_table_lock();<br>
+ hipe_mfa_info_table_rwlock();<br>
lst = BIF_ARG_1;<br>
while (is_list(lst)) {<br>
if (!term_to_mfa(CAR(list_val(lst)), &mfa))<br>
@@ -1455,7 +1466,7 @@ BIF_RETTYPE hipe_bifs_invalidate_funinfo<br>
}<br>
}<br>
}<br>
- hipe_mfa_info_table_unlock();<br>
+ hipe_mfa_info_table_rwunlock();<br>
if (is_not_nil(lst))<br>
BIF_ERROR(BIF_P, BADARG);<br>
BIF_RET(NIL);<br>
@@ -1469,7 +1480,7 @@ void hipe_mfa_save_orig_beam_op(Eterm mo<br>
orig_beam_op = pc[0];<br>
if (orig_beam_op != BeamOpCode(op_hipe_trap_call_closure) &&<br>
orig_beam_op != BeamOpCode(op_hipe_trap_call)) {<br>
- hipe_mfa_info_table_lock();<br>
+ hipe_mfa_info_table_rwlock();<br>
p = hipe_mfa_info_table_put_locked(mod, fun, ari);<br>
#ifdef DEBUG_LINKER<br>
printf("%s: ", __FUNCTION__);<br>
@@ -1478,7 +1489,7 @@ void hipe_mfa_save_orig_beam_op(Eterm mo<br>
#endif<br>
p->beam_code = pc;<br>
p->orig_beam_op = orig_beam_op;<br>
- hipe_mfa_info_table_unlock();<br>
+ hipe_mfa_info_table_rwunlock();<br>
} else {<br>
#ifdef DEBUG_LINKER<br>
printf("%s: ", __FUNCTION__);<br>
@@ -1505,7 +1516,8 @@ static void *hipe_make_stub(Eterm m, Ete<br>
return StubAddress;<br>
}<br>
<br>
-static void *hipe_get_na_nofail_locked(Eterm m, Eterm f, unsigned int a, int is_remote)<br>
+/* PRE: called with read or write lock held */<br>
+static void *hipe_get_na_try_locked(Eterm m, Eterm f, unsigned int a, int is_remote, struct hipe_mfa_info **pp)<br>
{<br>
struct hipe_mfa_info *p;<br>
void *address;<br>
@@ -1523,7 +1535,20 @@ static void *hipe_get_na_nofail_locked(E<br>
address = p->remote_address;<br>
if (address)<br>
return address;<br>
- } else<br>
+ }<br>
+ /* Caller must take the slow path with the write lock held, but allow<br>
+ it to avoid some work if it already holds the write lock. */<br>
+ if (pp)<br>
+ *pp = p;<br>
+ return NULL;<br>
+}<br>
+<br>
+/* PRE: called with write lock held */<br>
+static void *hipe_get_na_slow_locked(Eterm m, Eterm f, unsigned int a, int is_remote, struct hipe_mfa_info *p)<br>
+{<br>
+ void *address;<br>
+<br>
+ if (!p)<br>
p = hipe_mfa_info_table_put_locked(m, f, a);<br>
address = hipe_make_stub(m, f, a, is_remote);<br>
/* XXX: how to tell if a BEAM MFA is exported or not? */<br>
@@ -1531,14 +1556,34 @@ static void *hipe_get_na_nofail_locked(E<br>
return address;<br>
}<br>
<br>
+/* PRE: called with write lock held */<br>
+static void *hipe_get_na_nofail_locked(Eterm m, Eterm f, unsigned int a, int is_remote)<br>
+{<br>
+ struct hipe_mfa_info *p /*= NULL*/;<br>
+ void *address;<br>
+<br>
+ address = hipe_get_na_try_locked(m, f, a, is_remote, &p);<br>
+ if (address)<br>
+ return address;<br>
+<br>
+ address = hipe_get_na_slow_locked(m, f, a, is_remote, p);<br>
+ return address;<br>
+}<br>
+<br>
static void *hipe_get_na_nofail(Eterm m, Eterm f, unsigned int a, int is_remote)<br>
{<br>
- void *p;<br>
+ void *address;<br>
<br>
- hipe_mfa_info_table_lock();<br>
- p = hipe_get_na_nofail_locked(m, f, a, is_remote);<br>
- hipe_mfa_info_table_unlock();<br>
- return p;<br>
+ hipe_mfa_info_table_rlock();<br>
+ address = hipe_get_na_try_locked(m, f, a, is_remote, NULL);<br>
+ hipe_mfa_info_table_runlock();<br>
+ if (address)<br>
+ return address;<br>
+<br>
+ hipe_mfa_info_table_rwlock();<br>
+ address = hipe_get_na_slow_locked(m, f, a, is_remote, NULL);<br>
+ hipe_mfa_info_table_rwunlock();<br>
+ return address;<br>
}<br>
<br>
/* used for apply/3 in hipe_mode_switch */<br>
@@ -1617,7 +1662,7 @@ int hipe_find_mfa_from_ra(const void *ra<br>
/* Note about locking: the table is only updated from the<br>
loader, which runs with the rest of the system suspended. */<br>
/* XXX: alas not true; see comment at hipe_mfa_info_table.lock */<br>
- hipe_mfa_info_table_lock();<br>
+ hipe_mfa_info_table_rwlock();<br>
bucket = hipe_mfa_info_table.bucket;<br>
nrbuckets = 1 << hipe_mfa_info_table.log2size;<br>
mfa = NULL;<br>
@@ -1638,7 +1683,7 @@ int hipe_find_mfa_from_ra(const void *ra<br>
*f = mfa->f;<br>
*a = mfa->a;<br>
}<br>
- hipe_mfa_info_table_unlock();<br>
+ hipe_mfa_info_table_rwunlock();<br>
return mfa ? 1 : 0;<br>
}<br>
<br>
@@ -1715,7 +1760,7 @@ BIF_RETTYPE hipe_bifs_add_ref_2(BIF_ALIS<br>
default:<br>
goto badarg;<br>
}<br>
- hipe_mfa_info_table_lock();<br>
+ hipe_mfa_info_table_rwlock();<br>
callee_mfa = hipe_mfa_info_table_put_locked(callee.mod, callee.fun, callee.ari);<br>
caller_mfa = hipe_mfa_info_table_put_locked(caller.mod, caller.fun, caller.ari);<br>
<br>
@@ -1731,7 +1776,7 @@ BIF_RETTYPE hipe_bifs_add_ref_2(BIF_ALIS<br>
ref->flags = flags;<br>
ref->next = callee_mfa->referred_from;<br>
callee_mfa->referred_from = ref;<br>
- hipe_mfa_info_table_unlock();<br>
+ hipe_mfa_info_table_rwunlock();<br>
<br>
BIF_RET(NIL);<br>
<br>
@@ -1751,12 +1796,12 @@ BIF_RETTYPE hipe_bifs_mark_referred_from<br>
<br>
if (!term_to_mfa(BIF_ARG_1, &mfa))<br>
BIF_ERROR(BIF_P, BADARG);<br>
- hipe_mfa_info_table_lock();<br>
+ hipe_mfa_info_table_rwlock();<br>
p = hipe_mfa_info_table_get_locked(mfa.mod, mfa.fun, mfa.ari);<br>
if (p)<br>
for (ref = p->referred_from; ref != NULL; ref = ref->next)<br>
ref->flags |= REF_FLAG_PENDING_REDIRECT;<br>
- hipe_mfa_info_table_unlock();<br>
+ hipe_mfa_info_table_rwunlock();<br>
BIF_RET(NIL);<br>
}<br>
<br>
@@ -1770,7 +1815,7 @@ static void hipe_purge_all_refs(void)<br>
struct hipe_mfa_info **bucket;<br>
unsigned int i, nrbuckets;<br>
<br>
- hipe_mfa_info_table_lock();<br>
+ hipe_mfa_info_table_rwlock();<br>
<br>
bucket = hipe_mfa_info_table.bucket;<br>
nrbuckets = 1 << hipe_mfa_info_table.log2size;<br>
@@ -1792,7 +1837,7 @@ static void hipe_purge_all_refs(void)<br>
erts_free(ERTS_ALC_T_HIPE, mfa);<br>
}<br>
}<br>
- hipe_mfa_info_table_unlock();<br>
+ hipe_mfa_info_table_rwunlock();<br>
}<br>
<br>
BIF_RETTYPE hipe_bifs_remove_refs_from_1(BIF_ALIST_1)<br>
@@ -1809,7 +1854,7 @@ BIF_RETTYPE hipe_bifs_remove_refs_from_1<br>
<br>
if (!term_to_mfa(BIF_ARG_1, &mfa))<br>
BIF_ERROR(BIF_P, BADARG);<br>
- hipe_mfa_info_table_lock();<br>
+ hipe_mfa_info_table_rwlock();<br>
caller_mfa = hipe_mfa_info_table_get_locked(mfa.mod, mfa.fun, mfa.ari);<br>
if (caller_mfa) {<br>
refers_to = caller_mfa->refers_to;<br>
@@ -1840,7 +1885,7 @@ BIF_RETTYPE hipe_bifs_remove_refs_from_1<br>
}<br>
caller_mfa->refers_to = NULL;<br>
}<br>
- hipe_mfa_info_table_unlock();<br>
+ hipe_mfa_info_table_rwunlock();<br>
BIF_RET(am_ok);<br>
}<br>
<br>
@@ -1859,7 +1904,7 @@ BIF_RETTYPE hipe_bifs_redirect_referred_<br>
<br>
if (!term_to_mfa(BIF_ARG_1, &mfa))<br>
BIF_ERROR(BIF_P, BADARG);<br>
- hipe_mfa_info_table_lock();<br>
+ hipe_mfa_info_table_rwlock();<br>
p = hipe_mfa_info_table_get_locked(mfa.mod, mfa.fun, mfa.ari);<br>
if (p) {<br>
prev = &p->referred_from;<br>
@@ -1890,7 +1935,7 @@ BIF_RETTYPE hipe_bifs_redirect_referred_<br>
}<br>
}<br>
}<br>
- hipe_mfa_info_table_unlock();<br>
+ hipe_mfa_info_table_rwunlock();<br>
BIF_RET(NIL);<br>
}<br>
<br>
<br></blockquote></div><br></div>