forked from pool/util-linux
84 lines
2.5 KiB
Diff
84 lines
2.5 KiB
Diff
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From 2fa4168c8bc9d5438bc1dfadda293c7c21b6fa59 Mon Sep 17 00:00:00 2001
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From: Michael Trapp <michael.trapp@sap.com>
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Date: Mon, 6 Mar 2023 10:40:20 +0000
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Subject: [PATCH] libuuid: fix lib internal cache size
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The lib internal cache improves throughput in high load
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scenarios but for applications with a low request rate,
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the cache size must be adapted to this situation.
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Therefore the cache size should be changed to the current
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requirements of the application during runtime.
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---
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libuuid/src/gen_uuid.c | 30 ++++++++++++++++++++++--------
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1 file changed, 22 insertions(+), 8 deletions(-)
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Index: util-linux-2.38.1/libuuid/src/gen_uuid.c
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===================================================================
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--- util-linux-2.38.1.orig/libuuid/src/gen_uuid.c
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+++ util-linux-2.38.1/libuuid/src/gen_uuid.c
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@@ -442,25 +442,35 @@ int __uuid_generate_time(uuid_t out, int
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*/
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static int uuid_generate_time_generic(uuid_t out) {
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#ifdef HAVE_TLS
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+ /* thread local cache for uuidd based requests */
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+ const int cs_min = (1<<6);
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+ const int cs_max = (1<<18);
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+ const int cs_factor = 2;
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THREAD_LOCAL int num = 0;
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- THREAD_LOCAL int cache_size = 1;
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+ THREAD_LOCAL int cache_size = cs_min;
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+ THREAD_LOCAL int last_used = 0;
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THREAD_LOCAL struct uuid uu;
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THREAD_LOCAL time_t last_time = 0;
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time_t now;
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- if (num > 0) {
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+ if (num > 0) { /* expire cache */
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now = time(NULL);
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- if (now > last_time+1)
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+ if (now > last_time+1) {
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+ last_used = cache_size - num;
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num = 0;
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+ }
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}
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- if (num <= 0) {
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+ if (num <= 0) { /* fill cache */
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/*
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* num + OP_BULK provides a local cache in each application.
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* Start with a small cache size to cover short running applications
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- * and increment the cache size over the runntime.
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+ * and adjust the cache size over the runntime.
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*/
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- if (cache_size < 1000000)
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- cache_size *= 10;
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+ if ((last_used == cache_size) && (cache_size < cs_max))
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+ cache_size *= cs_factor;
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+ else if ((last_used < (cache_size / cs_factor)) && (cache_size > cs_min))
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+ cache_size /= cs_factor;
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+
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num = cache_size;
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if (get_uuid_via_daemon(UUIDD_OP_BULK_TIME_UUID,
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@@ -470,9 +480,11 @@ static int uuid_generate_time_generic(uu
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num--;
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return 0;
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}
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+ /* request to daemon failed, reset cache */
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num = 0;
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+ cache_size = cs_min;
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}
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- if (num > 0) {
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+ if (num > 0) { /* serve uuid from cache */
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uu.time_low++;
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if (uu.time_low == 0) {
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uu.time_mid++;
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@@ -481,6 +493,8 @@ static int uuid_generate_time_generic(uu
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}
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num--;
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uuid_pack(&uu, out);
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+ if (num == 0)
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+ last_used = cache_size;
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return 0;
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}
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#else
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